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A Cool-Arid Climate with Large Temperature Seasonality Implied by Arboreal Pollen in the Early Holocene, NorthCentral China
Fang Tian, Meijiao Chen, Qinghai Xu, Xianyong Cao
 doi: 10.1007/s12583-023-1920-3
[Abstract](0) [PDF 567KB](0)
Investigation of oil content in lacustrine shale-oil systems: Insights from two different pyrolysis
YUPING WU, Chinglin Liu, Fujie Jiang, Tao Hu, Chenxi Zhang, Jiahao Lv, Renda Huang, Meiling Hu, Guanyun Wu, Rizwan Sarwar Awan
 doi: 10.1007/s12583-023-1814-6
[Abstract](850) [PDF 1935KB](51)
This research has investigated the oil content of lacustrine shale-oil systems from the Junggar Basin. Twenty-eight samples are used for different pyrolysis experiments to study the characteristics of shale oil occurrence and the difference between various evaluation methods. Additionally, the factors affecting the physical states of shale oil are discussed. Compared with the standard Rock-Eval, the two-step pyrolysis and multi-step pyrolysis can eliminate the influence of the carryover effect. Therefore, these two types of pyrolysis are used to obtain the total, free, and adsorbed oil yield of the shale. The results demonstrate that the total oil yield acquired by multi-step pyrolysis is quite similar to that obtained by two-step pyrolysis. Both of them can prevent the retained oil yield from being underestimated by more than 50%. However, the free oil yield obtained by multi-step pyrolysis is significantly higher than that obtained by two-step pyrolysis. The multi-step pyrolysis can easily exaggerate the real free oil yield in resource evaluation. Therefore, this article suggests using the two-step pyrolysis to evaluate the characteristics of petroleum in shales. Furthermore, the amount of hydrocarbons within shales is related to organic matter properties. The higher the organic matter richness, the higher the total/adsorbed oil yield within the shale before reaching the adsorption saturation. The better the kerogen type, the higher the amount of liquid hydrocarbons within shales. As the thermal evolution of shales increases, the free oil proportion and the mobility of petroleum increase. This study compared different pyrolysis methods, which provided new insight for obtaining the oil content of shales, a key parameter of shale oil resource evaluation.
Application of unmanned aerial vehicle remote sensing on dangerous rock mass identification and deformation analysis: case study of a high-steep slope in an open pit mine
Wenjie Du, Qian Sheng, Xiaodong Fu, Jian Chen, Jingyu Kang, Xin Pang, Daochun Wan, Wei Yuan
 doi: 10.1007/s12583-023-1813-7
[Abstract](331) [PDF 4237KB](96)
Source identification and deformation analysis of disaster bodies are the main contents of high-steep slope risk assessment, the establishment of high-precision model and the quantification of the fine geometric features of the slope are the prerequisites for the above work. In this study, based on the UAV remote sensing technology in acquiring refined model and quantitative parameters, a semi-automatic dangerous rock identification method based on multi-source data is proposed; In terms of the periodicity UAV-based deformation monitoring, the monitoring accuracy is defined according to the relative accuracy of multi-temporal point cloud. Taking a high-steep slope as research object, the UAV equipped with special sensors was used to obtain multi-source and multi-temporal data, including high-precision DOM and multi-temporal 3D point clouds. The geometric features of the outcrop were extracted and superimposed with DOM images to carry out semi-automatic identification of dangerous rock mass, realizes the closed-loop of identification and accuracy verification; changing detection of multi-temporal 3D point clouds was conducted to capture deformation of slope with centimeter accuracy. The results show that the multi-source data-based semi-automatic dangerous rock identification method can complement each other to improve the efficiency and accuracy of identification, and the UAV-based multi-temporal monitoring can reveal the near real-time deformation state of slopes.
Organic matter occurrence and its effects on pore structure and methane adsorption capacity capacity: A case study of the Niutitang black shale in Guizhou, China
Peng Xia, Fang Hao, Jinqiang Tian, Yong Fu, Chuan Guo, Zhen Yang, Yuliang Mou, Ke Wang
 doi: 10.1007/s12583-022-1688-z
[Abstract](1183) [PDF 5313KB](89)
The black shale samples from the Niutitang Formation in the Yangtze Block were sequentially treated using organic solvent extraction and wet chemical oxidation. The organic matter (OM) in the shales includes physically mobile OM (PmOM), chemically mobile OM (CmOM), and stable OM (StOM). The CmOM has the strongest CH4 adsorption capacity because it has the largest volume of micropores and mesopores. In contrast, the PmOM has a very negative effect on the CH4 adsorption because it is poreless. The XD shale is a siliceous shale, in which the quartz particles wrap partly OM, preventing extraction and oxidation. The SL shale is an argillaceous shale, in which most of the OM is combined with clay minerals to form organo-clay composites. In both the SL and XD shales, the OM that is extractable via organic solvents is distributed among the mineral particles and is interconnected. The conceptual model of marine black shale in different environments needs to be perfected in the future because quantitative and qualitative methods should be combined to clarify the relationship between the known OM types (e.g., pyrobitumen, solid bitumen, and solid kerogen) and the OM types identified in this study.
Multivariate statistical analysis of dominating groundwater mineralization and hydrochemical evolution in Gao, northern Mali
TRAORE ADIARATOU, Xumei Mao, Alhousseyni Traore, YAHAYA YAKUBU, Aboubacar Sidibe
 doi: 10.1007/s12583-022-1689-y
[Abstract](104) [PDF 1783KB](32)
Population growth and expanding urbanization have caused persistent shortages and contamination of groundwater resources in Mali, Africa. The increase in groundwater salinity makes it more difficult for residents to obtain drinking water, it is necessary to clarify the causes and control factors of groundwater mineralization in Gao region, northern Mali. Based on the analysis of the hydrochemical composition of groundwater in 24 boreholes, Piper and Schöeller diagrams, principal component analysis (PCA) and hierarchical cluster analysis (HCA) are used to carry out multivariate statistical analysis on the main ions. The results show that the groundwater samples are weakly alkaline, with pH values ranging from 5.83 to 8.40, and the average values of boreholes are 7.50, respectively. The average electrical conductivity (EC) value is 354.4 (µS/cm), and the extreme value is between 124.0 and 1247 (µS/cm). Water is usually mineralized and presents nine types of water phase. The three principal components explain 84.42% of the total variance for 13 parameters. The factor F1 (58.85%), the factor F2 (16.88%) and the factor F3 (8.69%) present for the majority of the total data set. In addition, multivariate statistical analysis confirmed the genetic relationship among aquifers and identified three main clusters. Clustering related to groundwater mineralization (F1), clustering related to oxide reduction and iron enrichment (F2), and clustering of groundwater pollution caused by nitrate and magnesium (F3). We found that agriculture, weathering activities and dissolution of geological materials promote the mineralization of groundwater. Groundwater quality in the Gao region is becoming less and less potable because of increasing salinity.
Spatial and temporal evolution of lithospheric mantle beneath the eastern North China Craton: Constraints from mineral chemistry of peridotite xenoliths from the Miocene Qingyuan basalts and a regional synthesis
Jian-Fang Guo, Qiang Ma, Jianping Zheng, Yuping Su
 doi: 10.1007/s12583-022-1691-4
[Abstract](129) [PDF 5165KB](40)
Mineralogical data are presented for the peridotite xenoliths from Miocene (~19Ma) Qingyuan basalts in the eastern North China Craton (NCC), with the aim of constraining on property of the sub-continental lithospheric mantle (SCLM) beneath the northern Tan-Lu Fault zone (TLFZ) during the Cenozoic. The Qingyuan peridotites are dominated by spinel lherzolites with moderate-Mg# olivines (89.4 to 91.2), suggesting that the regional SCLM is mainly transitional and fertile. Light rare earth element (LREE)-depleted, slightly depleted and enriched clinopyroxenes (Cpx) are identified in different peridotites. Chemical compositions of the LREE-enriched Cpx and the presence of phlogopite suggest that the Qingyuan SCLM has experienced silicate-related metasomatism. The synthesis of available mineral chemical data of the mantle xenoliths across the NCC confirms the SCLM beneath the NCC is highly heterogeneous in time and space. The Mesozoic-Cenozoic SCLM beneath the TLFZ and neighboring regions are more fertile and thinner than that beneath the region away from the fault zone. The fertile and refractory peridotite xenoliths experienced varying degrees of silicate and carbonatite metasomatism, respectively. The spatial-temporal lithospheric mantle heterogeneity in composition, age and thickness suggest that the trans-lithosphere fault zone played an important role in heterogeneous replacement of refractory cratonic lithospheric mantle.
Trace element mobility in subducted marble and associated eclogite: constraints from UHP rocks in the Shuanghe area, central-east China
Xingao Hou, Zhiqiang Yu, Shefa Chen, Lei Liu, Yilin Xiao
 doi: 10.1007/s12583-022-1692-3
[Abstract](85) [PDF 5167KB](22)
In order to decipher element mobility in UHP meta-sedimentary rocks in the continental subduction zone, major and trace element compositions are investigated for a continuous profile from a representative UHP region in the Dabie Mountains. Among the lithologic contact zone, contents of K, Ca, LREE, and LILE exhibit varying degrees of downward trends in both marble and eclogite toward the contact zone, indicating that marble and their associated eclogite can release a large amount of K, Ca, and a small amount of LILEs and LREEs. Titanite is the main Ti phase in both marble and eclogite. Titanite rims around rutile can occasionally be seen in eclogite. Contents of Ti and HFSE exhibit a well-coupled relation among marble and eclogite, indicating that substantial Ti and HFSEs were migrated from eclogite to marble, in accord with the capacity of a melt medium. Rutiles and titanites in marble exhibit a relatively limited variation in Nb/Ta ratios (12.9-16.2), similar to those of titanites in eclogite (14.2-16.7), which demonstrates that rutiles and titanites in marble were sourced from eclogite because of short-distance migrations of Ti and HFSEs. According to the P-T path and the temperature and pressure conditions of the peak metamorphism reported by previous studies, the eclogite associated with marble may not form supercritical fluids in the subduction zone because of the addition of carbonate minerals.
Limitation of the Application of Heat Tracer in Investigating Groundwater and River Interactions under Dynamic Flow Conditions
Mengyan Ge, Rui Ma, Ziyong Sun
 doi: 10.1007/s12583-022-1683-4
[Abstract](119) [PDF 3970KB](22)
The groundwater (GW) in the floodplain riparian area frequently interacts intensely with surface water (SW). Heat as a tracer is one of the hot research fields in investigating GW-SW interactions, and analytical approaches have been proposed for the calculation of exchange flow velocity. However, few studies have considered the effects of very dynamic flow conditions and monitoring instrumentation on the calculation with field measured data. Herein, taking the middle reaches of the Heihe River as the study area, different types of monitoring wells were constructed under the riverbed and near the river, and multiple methods (Darcy’s law, heat tracing, and isotopic mixing methods) were employed to trace the exchanges between the river and groundwater. The results indicate that different methods demonstrate diverse information with obvious unevenly distributed flux along the vertical direction. And the combination of multiple methods has an important role in studying the interaction between GW and SW. Fully screened wells produce intraborehole flow and disturb the heat transport, which is relevant to flow velocity, and further affects the temperature distribution, impacting the temperature-based flow velocity calculation. Dynamic flow conditions aggravate riverbed sediment disturbances, e.g., scour and deposition, and additionally affect the interaction and monitoring data.
Geochemical Modeling of Fluid–Rock Interactions in Shallow buried Carbonate Reservoirs based on the Water Bath Instrument
Jiayi Ma, Anjiang Shen, Shuyun Xie, Min She, Huayun Tang, Emmanuel M. CARRANZA, Tianfu Zhang
 doi: 10.1007/s12583-022-1690-5
[Abstract](110) [PDF 2439KB](16)
Fluid–rock interaction plays a critical function in physical and chemical processes associated with the formation and evolution of oil and gas reservoir space. In the diagenetic stage of shallow burial, the dissolution of carbonate rocks by acidic fluids is conducive to the development of secondary pore space in reservoirs. In contrast, the free drift experiment based on water bath instrument can simulate the dissolution process of carbonate rocks in shallow burial environment effectively. In order to study the shallow burial dissolution mechanism of carbonate rocks in different acid solutions, 14 samples of typical carbonate rocks of Sinian, Cambrian, Ordovician, Permian and Triassic ages in the Tarim and Sichuan Basins, China were used. The dissolution experiments on carbonate rocks in sulfuric acid, acetic acid, hydrochloric acid, silicic acid and carbonic acid at shallow burial temperature (30℃≤T≤90℃) were carried out using a water bath instrument. The PHREEQC software was used to simulate the dissolution of carbonate minerals, in order to compare the results of constant temperature water bath experiment. The results show that acid solutions have significant dissolution effect on shallow burial carbonate rocks when T = 50–60℃, which corresponds to the burial depth of 1500–2000 m in the Tarim Basin and 1110–1480 m in the Sichuan Basin. However, there were obvious differences in the dissolution and reformation of carbonate rocks in different acids. In particular, sulfuric acid solution produced by thermochemical sulfate reduction can significantly promote the dissolution of carbonate rocks, especially dolomitic limestone. Moreover, the dissolution of limestone reservoirs is stronger than that of dolomite reservoirs in shallow burial. The results will provide new insights into the study of dissolution laws and influencing factors of carbonate reservoir space and the evaluation and prediction of carbonate reservoir in China.
Chronology, geochemistry and isotopic compositions of the Cretaceous Zhangjiakou diabase: Magmatic derivation and geodynamic implications
peng li, Dazhao Wang, guanzhong shi
 doi: 10.1007/s12583-022-1684-3
[Abstract](100) [PDF 6259KB](15)
Zircon U–Pb ages, major and trace elements and Sr–Nd–Hf isotope data of the diabase in the Zhangjiakou district were studied to investigate its derivation and tectonic implications. Zircon U–Pb ages indicate that the diabase was emplaced at ~130 Ma or younger, and captured zircons cluster at ~147 Ma, ~240 Ma, ~430 Ma and ~465 Ma. The diabase is characterized by minor variations in SiO2 (49.35–52.10 wt.%), TiO2 (1.65–1.77 wt.%), Al2O3 (17.00–18.26 wt.%), MgO (4.28–4.93 wt.%), CaO (6.69–7.90 wt.%) and Mg# (48–54). It has no significant Eu anomaly and displays enrichment in large ion lithophile elements (Rb, Ba and Sr) and depletion in high field strength elements (Nb, Ta, P and Ti). The diabase exhibits homogeneous Sr ((87Sr/86Sr)i = 0.70606–0.70701) and Nd (εNd(t) =–13.6 to –13.2) isotopic compositions. These features suggest that the parental magma was derived from partial melting of the ancient lower crust, relating to mantle upwelling that triggered by stagnant slabs or lithospheric detachment associated with the westward subduction of the Paleo-Pacific Plate. The Early Paleozoic inherited igneous zircons in the diabase suggest that the northern margin of the North China Craton (NCC) likely underwent southward subduction of the Paleo-Asian Ocean.
Characteristics of connected pores and evaluation of shale oil mobility in the Qianjiang Formation, Qianjiang Sag, Jianghan Basin,China
SUN Zhongliang, LI Zhiming, HE Chencheng, ZHU Feng, SHEN Baojian, LU Longfei
 doi: 10.1007/s12583-022-1699-9
[Abstract](354) [PDF 2527KB](33)
The connectivity of shale pores and the occurrence of movable oil in shales have long been a focus of research. In this paper, samples from Wells BX7 and BYY2 in the Eq34-10 cyclothem of Qianjiang Formation in the Qianjiang Depression, were analyzed. A double mercury injection method was used to distinguish between invalid and effective connected pores. The pore characteristics for occurrence of retained hydrocarbons and movable shale oil were distinguished based on comparison of pore changes in low temperature nitrogen adsorption and high pressure mercury injection experiments before and after extraction and the change in the mercury injection amounts in the pores between two separate mercury injections.. The results show that less than 50% of the total connected pores in the Eq34-10 cyclothem samples are effective. The development of effective connected pores affects the mobility of shale oil but varies with different lithofacies. The main factor limiting shale oil mobility in Well BX7 is the presence of pores with throat sizes less than 15nm. In Well BYY2, residual mercury in injection testing of lamellar dolomitic mudstone facies was mainly concentrated in pores with throats of 10~200 nm, and in bulk argillaceous dolomite facies it was mainly concentrated at 60~300nm. The throats of hydrocarbon-retaining pores can be 5nm or even smaller, but pores with movable shale oil in the well were found to have have throat sizes greater than 40nm. Excluding the influence of differences in wettability, the moveability of shale oil is mainly affected by differences in lithofacies, the degree of pore deformation caused by diagenesis, the complexity of pore structures, and the connectivity of pore throats. Dissolution and reprecipitation of halite also inhibit the mobility of shale oil.
Formation Mechanism of the Paleocene basal conglomerate, southwest Tarim Basin
yong Yue, Jingchun Tian, Chuanyan Huang
 doi: 10.1007/s12583-022-1696-z
[Abstract](102) [PDF 8039KB](11)
Abstract: Most knowledge about the Cretaceous-Paleogene strata in the Tarim Basin is mainly inferred from the outcrops at the basin’s margin,but first time in the basin. The formation mechanism of the Paleocene basal conglomerate was determined using geochemical isotopes of the breccia from well PBX1 in the southwestern Tarim Basin. The results showed that the global K/Pg (i.e., Cretaceous/Paleogene) clay layer boundary was located in the middle of the Paleocene basal conglomerate at the depth of 7066.75m in well PBX1. In the Late Cretaceous, associated with volcanic activities and earthquakes, the caldera in the PBX1 well block formed an annular depression with large elevation differences in response to the Pamir block collision. As a result, the collapsed breccia with storm tide genesis deposited at the periphery and inside of the depression, characterized by syn-sedimentary deformation. During the Paleocene, multiple sets of interbedded carbonate and collapsed breccia deposited in response to multi-phased transient transgression-regression cycles. The transportation of breccia exhibited near-source accumulation/extremely close or in-situ rapid accumulation. The studied region is located in the eastern end of the Tethys Sea, the Late Cretaceous-Early Paleocene breccia is of great significance for reconstructing the paleogeography of the Tarim basin in Tethys. Key words: South-western Tarim;Paleogene system;Breccia;Attribution and genesis
Contrasting behavior for Li-Mg isotopes during subduction: Insights from garnet in the Yardoi schists, Tibet
Xing Li, Yilin Xiao, Olivier Nadeau, Dongyong Li, Haiyang Liu, Zhang Zeming, Zhenhui Hou
 doi: 10.1007/s12583-022-1697-y
[Abstract](152) [PDF 4022KB](55)
It has long been recognized that garnet has the capacity to preserve the trace element and isotopic signature of distinct metamorphic growth zones because of its high closure temperature. Combined with the large size of certain garnet porphyroblast, this allows investigating variations in metamorphic conditions such as pressure, temperature, deviatoric stress, and fluid composition, which occur during subduction-related metamorphism. Here, one garnet porphyroblast of 6 cm diameter was sampled from the Yardoi schists of Tibet, and the major-, trace-, and Li-Mg isotopic compositions of distinct growth zones were determined in situ. The δ7Li values range from +6.0 ‰ to +4.1 ‰ and follow ‘S-shape’ patterns on both sides of the garnet’s core, revealing a two-stage growth process corresponding to the fluid-assisted sequential recrystallization of chlorite and micas during prograde metamorphism. By contrast, once corrected for the overprinting by retrograde metamorphism, the δ26Mg values vary monotonously from -1.73 ‰ in the core to -1.32 ‰ in the outer rim, reflecting a single-step process interpreted to result from increasing temperature and the solid-state recrystallization of chlorite-biotite during prograde metamorphism. This different behavior of Li and Mg isotopes is interpreted to result from the fact that Li is more fluid-mobile than the major element Mg.
Provenance of the southeastern South China Block in the Late Triassic and initiation of Paleo-Pacific subduction: Evidence from detrital zircon U–Pb geochronology
Jintao Kong, zhongjie Xu, Rihui Cheng, Duo Wan
 doi: 10.1007/s12583-022-1694-1
[Abstract](92) [PDF 7438KB](18)
During the late Paleozoic–early Mesozoic era, the sediment transport system and tectonic regime in the southeastern margin of the South China Block (SESCB) all changed, significantly affected by the Paleo-Pacific subduction. This study uses detrital zircon geochronology to discuss the Late Triassic source-to-sink system in the SESCB and provides some references for the Paleo-Pacific subduction process. The paleogeography and similarity of detrital zircon age distribution reveal three sinks in the SESCB during the Late Triassic: 1. the Yangchun–Kaiping–Gaoming area, comprising major age ranges of 260–220, 460–400, and 1,200–800 Ma, which might be sourced from the Yunkai Terrane; 2. the Jiexi–Kanshi–Nanjing area, characterized by the significant age component of 2,000–1,800 Ma, which corresponded to the Wuyi Terrane; 3. the Xinan area, consisting of significant age groups of 290–250 Ma and 380–320 Ma, which might be sourced from the magmatic rocks formed by the Huinan Movement and Paleo-Pacific subduction. The Upper Triassic strata contain many 290–250 Ma zircons, and their trace elements suggested a magmatic arc existed near the SESCB during the 290–250 Ma. Thus, we propose that the Paleo-Pacific subduction might have begun in the Early Permian.
Investigation on the deformation and failure patterns of loess cut slope based on the unsaturated triaxial test in Yan'an, China
Lina Ma, Shengwen Qi, Songfeng Guo, Qiangbing Huang, Xiaokun Hou, Linxin Zhang
 doi: 10.1007/s12583-021-1554-4
[Abstract](303) [PDF 5628KB](6)
The large-scale implementation of the Gully Stabilization and Land Reclamation (GSLR) project induces various failures of loess slopes due to excavation in Yan'an, China. However, the deformation and failure behavior of these excavated loess slopes have not been fully understood. In this study, field investigation was undertaken for analyzing the distributions and failure features of excavation-induced loess slope failures. It is found that plastic failure mainly occurs in Q3 loess layers and brittle failure in Q2. To understand the underlying failure mechanism, a series of triaxial shear tests were conducted on intact Q3 and Q2 loess samples that with different water contents, namely natural water content (natural), dry side of the natural value (drying 5%), and wet side (wetting 5%). The characteristics of stress-strain curves and failure modes of the samples were analyzed. Results show that the stress-strain curves of Q2 samples are dominated by strain-softening characteristics, while Q3 samples mainly exhibit strain-harden features except in the drying state. Correspondingly, shear failures of Q3 specimens are mainly caused by shear crack planes (single, X or V-shaped). For Q2 loess, the dominance of tensile cracks is observed on the surface of damaged specimens. These disclose the different failure modes of excavated slopes located in different strata, that is, the arc sliding failure of Q3 loess slopes and the stepped tensile failure of Q2 loess slopes, and are helpful in the design and management of the ongoing GSLR projects in the Loess Plateau.
Ore geology, H–O–C isotopes and 40Ar–39Ar dating of the Wutonggou iron deposit, eastern Tianshan, NW China: Implications for the source, timing, and genesis of hydrothermal mineralization in a sedimentary iron deposit
Chun-Long Wang, Yi‑Tian Wang
 doi: 10.1007/s12583-022-1686-1
[Abstract](116) [PDF 6300KB](25)
The Wutonggou iron deposit is located in the well-known iron metallogenic belt in the eastern Tianshan, NW China, and has been regarded as a sedimentary iron deposit. Hydrothermal overprinting could play indispensable roles in the formation of high-grade iron ores in sedimentary iron deposits, thus the nature and evolution of hydrothermal fluids have important implications on the genesis of these deposits. Consequently, an integrated study of ore geology, H–O–C isotopes and 40Ar–39Ar dating, is conducted on the Wutonggou deposit, in order to reveal the features, source, and timing of hydrothermal mineralization. The studied deposit includes two mining sections namely the Jianshan and Wutonggou. The δ18O values of early magnetite from the Jianshan section range from +3.0‰ to +5.8‰ that nearly consistent with classic magmatic magnetite, while increase to 6.3‰–8.0‰ in the late stage. Quartz from the two sections shows comparable H–O isotopic compositions and identical fractionation trends, and is plotted in or periphery to the primary magmatic water area. Calcites from the two sections are broadly similar in carbon and oxygen isotopic compositions, and siderite from the Wutonggou section is plotted in the same region. Thus, comparable stable isotopic compositions and evolution trends indicate similar magmatic fluids contributed hydrothermal iron mineralization in the two mining sections. Moreover, water-rock interactions of varying degrees generated distinct mineralization styles in the Jianshan and Wutonggou sections, and caused the isotopic fractionation in late stages. Biotite extracted from a hydrothermal siderite ore yielded a 40Ar–39Ar plateau age of 299.5 ± 2.0 Ma, indicating the timing of hydrothermal iron mineralization is corresponding to the emplacement of vicinity granitoids. Taken together, the hydrothermal mineralization in the Wutonggou iron deposit was the product of remobilization and upgrading of early sedimentary iron ores, and ore-forming fluids were most probably originated from regional granitic magmatism.
Characteristics and formation analysis of earth fissure in Anren area in Wei River Basin, China
Jianwei Qiao, Zhenjiang Meng, Yuyun Xia, Cong Liu, Quanzhong Lu, Feiyong Wang, Yuanqiang Zhou, Haiyuan Zhao
 doi: 10.1007/s12583-022-1653-x
[Abstract](269) [PDF 3547KB](20)
Since the 1950’s, 212 earth fissures have been discovered in the Wei River Basin. During a field survey in 2016, an additional 48 earth fissures were discovered in Anren area, northeast of the Wei River Basin. The characteristics and formation mechanisms of these fissures were studied through field investigations, measurements, trench excavation, and drilling. On-site investigations indicated that these earth fissures were distributed along a fault-controlled geomorphic boundary. Fissures trended at 60°–80° NE and were divided into five groups. Trenches revealed multiple secondary fissures, exposing severe soil ruptures in the shallow earth surfaces. Drilling profiles revealed that earth fissures dislocated several strata, and resembled synsedimentary faults. Seismic reflection profiles revealed buried faults beneath the earth fissures. The Anren area fissures formed in the following three stages: regional extension that initially generated multiple buried faults; seismic activity rupturing multiple strata, resulting in multiple buried fractures; and finally, erosion processes that propagated the buried fractures to the surface, forming the current earth fissures.
Geochronology and geochemistry of Permian Dashizhai Basin in Xing’an–Inner Mongolia Orogen: Implications for the evolution of the Paleo-Asian Ocean
Chi Zhang, Guosheng Wang, Zhiguang Zhou, Shen Gao, Neng Zhang, Liudong Wang, Erqiang Bo
 doi: 10.1007/s12583-022-1651-z
[Abstract](126) [PDF 21807KB](21)
The Xing’an–Inner Mongolia Orogen is a critical tectonic unit for constraining the evolution of the Paleo-Asian Ocean. However, the location and time for the closure of the Paleo-Asian Ocean are still debated. Here, we select a representative basin in Dashizhai in northeastern China, using U-Pb zircon geochronology and geochemistry to analyze the sedimentary facies, depositional ages, and provenance. The results show that the age of the Dashizhai Formation range from 400 to 347 Ma, the Shoushangou Formation range from 400 to 348 Ma, the Zhesi Formation range from 307 to 252 Ma, and the Linxi Formation range from 299 to 241 Ma. The Dashizhai Formation is composed of metamorphic andesite and clastic rocks. The Shoushangou Formation comprises siltstone, rhyolite, and argillaceous siltstone. The Zhesi and Linxi Formations are composed of mudstone and argillaceous siltstone. Geochemical data shows that these rocks are enriched in light rare earth elements and depleted in Eu with various La/Sc, Th/Sc, and La/Co ratios. The Permian Dashizhai Basin is from Permian volcanic and felsic igneous rocks from the Ergun, Xing’an, and Songliao blocks. The absence of the Late Carboniferous strata in the Dashizhai Basin indicates an extension setting during this period. Furthermore, we suggest the Xing’an–Inner Mongolia Orogen was an uplifting process associated with evolution the Paleo-Asian Ocean during the Late Permian.
Effect of Reclamation on the Groundwater-Lake Water Interaction in Chen Lake
Kun Lei, Teng Ma, Liu Chen, Zhen Li, Yu Chen
 doi: 10.1007/s12583-022-1652-y
[Abstract](99) [PDF 3200KB](23)
Chen Lake has been seriously modified by reclamation to expand the residential and agricultural area. Lake reclamation can decrease water quantity, cause water quality problems, and degrade water ecological function. To clarify the interaction between groundwater and lake water influenced by reclamation, water level and hydrochemical characteristics of five groundwater nests and three lake sites were monitored. Results emphasize that the seasonal fluctuations of lake water level is an important factor for both recharge and maintaining groundwater levels in study area. Groundwater in reclaimed farmland have seasonal patterns following lake water with a lag time. Noteworthy, the lag time of porewater in reclaimed farmland is one month longer than confined water. HCA showed that lake water and groundwater samples in same cluster were characterized by high δD, δ18O, Cl- and K+, suggesting the provision of lake to groundwater systems and the transfer of chemical signature. Other Cluster was dominated by reclaimed farmland groundwater samples and enriched in Ca2+, HCO3-, Si. This finding interpreting that water-rock interaction is the predominant process in reclaimed farmland. As a result, there is a high degree of connectivity between lake water and underlying groundwater. However, porewater hydrodynamic conditions gradually weaken and groundwater recharge in reclaimed farmland is modified after large-scale reclamation.
Diverse climatic and anthropogenic impacts on desertification in the middle reaches of Yarlung Zangbo River catchment on the Tibetan Plateau
Yu Qi, Xianyan Wang, Zhiyong Han, Xiaodong Miao, Huayu Lu
 doi: 10.1007/s12583-022-1658-5
[Abstract](112) [PDF 1450KB](22)
The unique desertification under alpine climate and ecosystem on Tibetan Plateau could provide critical clues on the natural and anthropogenic impacts on desertification. This study used the Landsat data to investigate the distributions of desertification from 1990 to 2020 in two areas (Shannan and Mainling), within the Yarlung Zangbo River Basin. The results show not only different spatial distributions but also various temporal changes of desertification. In Shannan, aeolian sand is distributed in wide areas from valley floor to mountain slope, while in Mainling, it is distributed sporadically at the footslope. The aeolian sandy land expanded at first, followed by a long-term shrinkage in Shannan. While in Mainling, it steadily expanded and then followed by a fast decrease. These changes are attributed to climate change and anthropogenic factors. The increase in temperature causes desertification expansion in Shannan, while favorable climate along with decreasing human activity promotes desertification reversal. However, both the expansion and shrinkage of desertification are sensitive to human activity in Mainling. This show diverse responses of desertification to natural and anthropogenic impacts on different backgrounds of climatic and vegetation coverage. A threshold of climatic conditions could control the dominant factor in desertification from natural to anthropogenic elements.
3D Distinct Element Back Analysis Based on Rock Structure Modelling of SfM Point Clouds: The Case of the 2019 Pinglu Rockfall of Kaili, China
Zhen Ye, Qiang Xu, Qian Liu, Xiujun Dong, Feng Pu
 doi: 10.1007/s12583-022-1667-4
[Abstract](99) [PDF 9435KB](13)
This paper introduces the use of point cloud processing for extracting 3D rock structure and the 3DEC -related reconstruction of slope failure, based on a case study of the 2019 Pinglu rockfall. The basic processing procedure involves: (1) computing the point normal for HSV-rendering of point cloud; (2) automatically clustering the discontinuity sets; (3) extracting the set-based point clouds; (4) estimating of set-based mean orientation, spacing, and persistence; (5) identifying the block-forming arrays of discontinuity sets for the assessment of stability. The effectiveness of our rock structure processing has been proved by 3D distinct element back analysis. The results show that SfM modelling and rock structure computing provides enormous cost, time and safety incentives in standard engineering practice.
Late Miocene elevated horizontal karst caves and landform evolution as a response to tectonic uplift along with regional integration of fluvial drainage in Southwestern China
Min Zhai, Xinggong Kong, Yuanhai Zhang, Philip Rowsell, Zhijun Zhao, Baojian Huang, Jing Zhang
 doi: 10.1007/s12583-022-1656-7
[Abstract](210) [PDF 14363KB](15)
In Southwestern China, the development of karst landforms and the planation surfaces is closely related to local tectonics, fluvial incision and base level change, as well as climate change. While researches on when these karst landforms and planation surfaces formed and how they evolved along drainage development are scarce. Fortunately, horizontal caves with numerous fluvial deposits in high karst mountains can be used as time markers in landform evolution. Here we select large horizontal caves to perform studies of geomorphology, sedimentology and geochronology. Field work shows that more than 25 km long horizontal cave passages are perched 1500 m higher than the local base level, but filled with several phases of fluvial sediments and breakdown slabs. The first phase of fluvial gravels and related cave drainage were dated back to 6.4 Ma using cosmogenic nuclide burial dating, and the stalagmite covering the cave collapse was dated by the U-Pb method , older than 1.56 Ma. These results show that the continuous horizontal cave drainage system and the planation surface were developed prior to the Late Miocene. The lowering process of the base level as a result of the sharp fluvial incision and water level lowering, along with the regional uplift, led to the abandonment of the horizontal cave and the elevated planation surface at the Late Miocene . After that, the phase of cave collapse , thick fluvial sand and clay sediments in the caves from the recharge of the cave deposited at around 1.6 Ma and during the Middle Pleistocene, respectively. Subsequently, speleothems widely deposited on the collapse and clay sediment during the period from 600 to 90 ka ,whereas the deposition of cave fluvial sediments terminated suddenly. The tectonic could control the denudation of surface caprock and the development of karst conduits prior to the Late Miocene, whereas the river incision acted as the main driver for the base level lowering and the destruction of the horizontal cave drainage at high altitude. In addition, the rapid incision and the retreat of Silurian gorges finally caused the formation of karst mesa in the Middle Pleistocene.
Source-to-sink relationships between the Qaidam Basin (North Tibet) and its surrounding mountain ranges: New insights from detrital zircon U–Pb ages in modern river sediments
Xu Zhang, Bowen Song, Tinglu Yang, Yafei Hou, Yibo Yang, Keke Ai, Jiaxuan Wang, Zhang Kexin
 doi: 10.1007/s12583-022-1666-5
[Abstract](189) [PDF 7269KB](36)
The Cenozoic source-to-sink history of the Qaidam Basin is crucial for understanding of the basin-filling architecture, mountain-building processes and even the dynamics of the Tibetan plateau growth. However, the provenance history of Cenozoic strata in the Qaidam Basin remains ambiguous, especially in the northern Qaidam Basin. This controversy highlights the importance of obtaining the spatial source-to-sink relationships between the Qaidam Basin and its surrounding mountain ranges. In this study, we investigated the detrital zircon U–Pb ages of modern fluvial systems draining the Eastern Kunlun Shan. Their detrital zircon age distributions fall into five age groups: 300-190, 530-360, 1000-560, 2000-1100 and 2650-2000 Ma. The dominant age groups are 530-360 and 300-190 Ma, which represent the successive subduction of the Proto-Tethys and Paleo-Tethys Oceans and the subsequent continental collisions, respectively. Combining these new detrital zircon U–Pb ages with available age datasets, we finally obtained complete detrital zircon age information for modern fluvial systems in the whole Qaidam Basin. The U–Pb age distributions of modern river sands reveal that the zircon age signature of basement rocks in the Eastern Kunlun Shan is significantly different from that in the South Qilian Shan but is similar to that in the Altyn Tagh Shan. Moreover, these zircon age observations were confirmed by the significant difference in the Nd isotopic signature of modern river sands, which reveals a significant difference between the Eastern Kunlun Shan and South Qilian Shan in the formation and evolution process.
Karst trough control of solute transport processes at two karst groundwater flow systems, Western Hubei, Central China
Yi'an Wang, Ruichao Zhao, Lin Ding, Shuai Xiong, Yin Li, Jianwei Bu, Wei Chen, Hong Zhou, Wei Liu
 doi: 10.1007/s12583-022-1665-6
[Abstract](256) [PDF 3313KB](50)
To investigate groundwater flow and solute transport characteristics of the karst trough zone in China, tracer experiments were conducted at two adjacent typical karst groundwater flow systems (Yuquandong (YQD) and Migongquan (MGQ)) in Sixi valley, western Hubei, China. High-resolution continuous monitoring was utilized to obtain breakthrough curves (BTCs), which were then analyzed using the multi-dispersion model (MDM) and the two-region nonequilibrium model (2RNE) with basic parameters calculated by CXTFIT and QTRACER2. Results showed that: (1) YQD flow system had a complex infiltration matrix with overland flow, conduit flow and fracture flow, while the MGQ flow system was dominated by conduit flow with fast flow transport velocity, but also small amount of fracture flow there; (2) they were well fitted based on the MDM (R2=0.928) and 2RNE (R2=0.947) models, indicating that they had strong adaptability in the karst trough zone; (3) conceptual models for YQD and MGQ groundwater systems were generalized. In YQD system, the solute was transported via overland flow during intense rainfall, while some infiltrated down into fissures and conduits. In MGQ system, most were directly transported to spring outlet in the fissure-conduit network.
Physical prediction model of compound hydrodynamic unload-load response ratio and its application in reservoir colluvium landslide
Lu Guo, Keqiang HE, Honghua Liu, Fandi Meng, Xuchun Wang
 doi: 10.1007/s12583-022-1662-9
[Abstract](91) [PDF 1406KB](10)
It is well known that the deformation and damage of reservoir colluvium landslides are often determined by the combined dynamics of reservoir water level change and rainfall. Based on the systematic analysis of the change law of reservoir water level, rainfall and displacements of reservoir colluvium landslide, this paper proposes the compound hydrodynamic action of rainfall and reservoir water as the unload-load parameter, and the landslide displacement as the unload-load response parameter. Based on this, a physical prediction model of the compound hydrodynamic unload-load response ratio of reservoir colluvium landslide was established, and the quantitative relationship between the compound hydrodynamic unload-load response ratio and its stability evolution was in-depth analyzed and determined. On the basis of the above research, taking Shuping landslide, a typical hydrodynamic pressure landslide as an example, the unload-load response ratio model is used to systematically evaluate and predict the stability evolution law and the change trend of the landslide under compound hydrodynamic action. The prediction result shows that the variation law of the compound hydrodynamic unload-load response ratio is consistent with the dynamic evolution law of its stability. Therefore, the above studies show that the compound hydrodynamic unload-load response ratio parameter is an effective displacement dynamic evaluation parameter for reservoir colluvium landslides, so it can be used in the prediction of the reservoir colluvium landslides.
Effect of the tectonic inversion on the Source-to-sink system evolution in a lacustrine rift basin, a case study of South Yellow Sea Basin, East China.
Xue Fan, Chao Fu, Shengli Li, Shunli Li
 doi: 10.1007/s12583-022-1664-7
[Abstract](107) [PDF 10495KB](20)
The complex plate collision process led the South Yellow Sea Basin (SYSB) to go through an intensity tectonic inversion during the early Cenozoic, which led to a regional unconformity surface development. As a petroliferous basin, SYSB saw intensity denudation and deposition process, making it hard to characterize their source-to-sink system(S2S), and this study provided a new sight to reveal them quantitatively. According to the seismic interpretation, it was found that two types of tectonic inversion led to the strata shortening process, which was classified according to their difference in planar movements, dip-slip faults, and strike-slip ones. As for dip-slip faults, the inversion structure was primarily formed by the dip-slip movement and many fault-related folds developed, which mainly developed in the North Depression Zone of the SYSB. The strike-slip ones, accompanying developed with some negative flower structures, are dominated in the South Depression Zone of the SYSB. Then, to reveal its source-to-sink system in the tectonic inversion basin, we speculated the sediments’ provenance area and their migration distance, referring to the zircon U-Pb data and heavy mineral assemblage. As for the North Depression Zone, it is shown that fewer distal sediments from the West Sulu Orogenic Belt are infilled, and proximal slump or fan delta are prominently developed during the tectonic inversion stage. The provenance rebuild in the South Depression Zone shows increasing sediments from the proximal area (Central Uplift Zone in SYSB and Wunansha Uplift) and the prograding delta long-axis parallel to these boundary faults during the tectonic inversion stage. Calculations were conducted on the coarse sediments content, faults displacements, catchment relief, sediments migration distance, and discussions about the impact factors to the Source-to-sink system developed in various strata shortening patterns with a statistical method. It was found that, within the dip-slip faults-dominated zone, the volume of the sediment routing system and the ratio of coarse-grained sediments merely has a relationship with the amount of sediment supply and average faults broken displacement. Compared with the strike-slip faults-dominated zone, the source-to-sink system shows a lower level of sandy sediment influx, and its coarse-grained content is mainly determined by the average faults broken displacement.
System reliability analysis of reservoir landslides: Insights from long-term reservoir operation
Kang Liao, Yiping Wu, Fasheng Miao
 doi: 10.1007/s12583-022-1668-3
[Abstract](148) [PDF 4819KB](24)
The reservoir operation awakens numerous landslides with multiple sliding surfaces known as reservoir landslides, and the systematic stability analysis for such landslides is becoming increasingly urgent. Taking the Majiagou landslide as an example, this paper analyses the comprehensive performance of the landslide from a probabilistic point of view. Under a reservoir operation cycle, a series of numerical analyses are carried out to simulate the migration of the seepage field, then the dynamic stability of the landslide is quantified accordingly. Subsequently, the wetting-drying cycles test is used to model the weakening of strength parameters in hydro-fluctuation belt under the long-term reservoir operation. Considering the weakening effect of long-term reservoir operation on the hydro-fluctuation belt, the system reliability is evaluated using the Ditlevsen's bounds. The results suggest that the reservoir operation can affect the stability of the landslide by changing the seepage field. The system failure probability gradually rises as the number of wetting-drying cycles increases. Compared with conventional probabilistic analysis that calculates the failure probability of each sliding surface mechanically, analyzing the landslide in terms of system reliability can effectively narrow the failure probability range, which provides an insightful idea for evaluating the systematic stability of analogous reservoir landslides.
In-situ horizontal extrusion test of herbaceous root–soil with different root types
Fangcui Liu, Shengwen Qi, Shenglin Qi, Xiaokun Hou, Yanrong Li, Guangming Luo, Lei Xue, Xueliang Wang, Juanjuan Sun, Songfeng Guo, Bowen Zheng
 doi: 10.1007/s12583-022-1661-x
[Abstract](184) [PDF 7426KB](27)
The influence of different types of roots on the soil is complex and still remains unclear. Four in-situ extrusion tests were conducted on two types of root systems, namely fibrous and tap root system, for three plants (i.e. Eleusine indica, Potentilla anserine and Artemisia argyi), according to the classification in Botany, and the thrust–displacement curves and failure patterns of different samples were analysed by comparison to fill the aforementioned gap. Results reveal that the roots can reduce the characteristics of soil brittleness and enhance its capability to resist large deformation, and different root types contribute different effects on the strain-hardening behaviour of the root–soil mass. The contribution of the fibrous root system on strength is limited, whilst the tap root system substantially enhances strength and stiffness. Results of failure patterns show that fibrous and tap root systems affect soil solidification and surface cracking reduction. However, the effect of the tap root system depends on the composition of lateral and tap roots: long and rich lateral roots are effective for resisting the creation of cracks, but thick tap roots with few and thin lateral roots may lead to several surface cracks.
Mechanism of interaction between anchored slide-resistant piles and landslides with weak-hard interbedded bedrock:model tests and theoretical interpretation
Guihua Wang, Changdong Li, Xin He, Taijiang Chen, Jie Meng, Wenmin Yao, Yongquan Zhang, HUAWEI ZHANG
 doi: 10.1007/s12583-022-1663-8
[Abstract](192) [PDF 3551KB](13)
Interactions between anchored slide-resistant piles and landslides with weak-hard interbedded bedrock have not yet been systematically studied. Physical models of landslides reinforced by anchored slide-resistant piles are investigated based upon the self-developed testing system. The landslide system evolution with increasing loading force is revealed; the internal force and deformation of anchored slide-resistant piles in weak-hard interbedded bedrock are analyzed. A single anchored pile in weak-hard interbedded bedrock is analyzed theoretically, and an optimized calculation method for the axial force of the anchor cable is proposed. The results show that (1) The landslide system evolves through four stages: creeping, coordinated deformation, uncoordinated deformation, and failure. (2) The thrust sharing ratio of the pile-anchor first increases, then decreases slightly, and finally stabilizes; the maximum thrust sharing ratio is 12.22. (3) The anchoring force provided by weak-hard interbedded bedrock is between those of homogeneous hard and homogeneous weak rocks. The horizontal displacement of the pile in homogeneous hard rock is small, but more thrust is borne by the pile, and vice versa. (4) The theoretical value for a single anchored pile calculated by the optimized method is close to the measured value. These findings provide a scientific basis for landslide control projects in areas with weak-hard interbedded bedrock.
Assessing the connectivity of a regional fractured aquifer based on a hydraulic conductivity field reversed by multi-well pumping tests and numerical groundwater flow modeling
Jingjing Lin, Rui Ma, Ziyong Sun, Liansong Tang
 doi: 10.1007/s12583-022-1674-5
[Abstract](94) [PDF 1578KB](14)
Aquifer connectivity could greatly affect groundwater flow and further control the contaminant transport in fractured medium. However, assessing connectivity of fractured aquifer at regional scales is still a challenge because such connectivity is difficult to measure directly. This study proposed a framework for assessing connectivity of a fractured aquifer, with Qitaihe area, Heilongjiang Province, northeastern China as an illustrating study area. The 3-D finite difference numerical models were established to interpret the results of three multi-well pumping tests and inversely estimate the distribution of hydraulic conductivity (K) in the fractured aquifer. A static connectivity metric of the minimum hydraulic resistance (MHR) was calculated, based on the optimized K-field, to evaluate the hydraulic connectivity in the aquifer, and the corresponding least resistance paths (LRPs) were identified. The results indicate that a better horizontal connectivity in the fractured aquifer in the northeastern and middle parts than in the southwestern part of the study area. The identified LRP indicated that the preferential flow channels at regional scales were controlled mainly by aquifer connectivity instead of local high-K zones.The results of this study can provide a method for aquifer connectivity estimation at regional scales.
Applications of deep learning in mineral discrimination: a case study of quartz, biotite and K-feldspar from granite
Wei Lou, Dexian zhang
 doi: 10.1007/s12583-022-1672-7
[Abstract](56) [PDF 5838KB](22)
Mineral recognition and discrimination play a significant role in geological study. Intelligent mineral discrimination based on deep learning has the advantages of automation, low cost, less time consuming and low error rate. In this manuscript, characteristics of quartz, biotite and K-feldspar from granite thin sections under cross-polarized light were studied for mineral images intelligent classification by Inception-v3 deep learning convolutional neural network (CNN), and transfer learning method. Dynamic images from multi-angles were employed to enhance the accuracy and reproducibility in the process of mineral discrimination. Test results show that the average discrimination accuracies of quartz, biotite and K-feldspar are 100.00%, 96.88% and 90.63%. Results of this study prove the feasibility and reliability of the application of convolution neural network in mineral images classification. This study could have a significant impact in explorations of complicated mineral intelligent discrimination using deep learning methods and it will provide a new perspective for the development of more professional and practical mineral intelligent discrimination tools.
Origin of burrow-associated dolomites and its reservoir implications: A case study from the Lower-Middle Ordovician carbonates of Tarim Basin (NW China)
Chuan Guo, Daizhao Chen, Yong Fu, Xiqiang Zhou, Cunge Liu
 doi: 10.1007/s12583-022-1673-6
[Abstract](61) [PDF 11140KB](35)
The Yingshan Formation of the Lower-Middle Ordovician in the Tarim Basin (NW China) was mainly deposited in a shallow platform, which was intensely bioturbated with burrows filled with both dolomites and calcites. This study aims to figure out the controls on the dolomitization of burrow infills and the effects on petroleum reservoir quality based on petrographic examination, fluid inclusion microthermometry, and isotopic (C-O-Sr) geochemical analyses. The differentiation of burrow-associated carbonates (dolomites and calcites) was likely controlled by the interactions of sea-level oscillations of variable orders and depositional environments. The burrow-associated dolomites (BADs) were precipitated in a relatively restricted (i.e., lagoon) depositional environment during the lowstand of long-term sea level. In contrast, the burrow-associated calcites (BACs) were formed in a water circulation-improved lagoonal environment during the transgression of long-term sea level. Isotopic geochemical data indicate that the BADs in the Yingshan Formation were formed from slightly saline (i.e., mesosaline to penesaline) seawater, whereas the BACs were precipitated from nearly normal seawater. In addition to the anoxic condition, the presence of marine-sourced organic matter and sulfate-reducing bacteria, and a sufficient supply of dolomitizing fluids enriched in magnesium ions (Mg2+) and their Mg2+ concentration may have played a critical role in the formation of BADs. In the more permeable and disturbed burrow sediments as a result of burrowing, penetrating fluids with higher salinities and higher Mg2+ concentration relative to seawater favored dolomite precipitation. The fluids with seawater-like Mg2+ concentration, however, would lead to calcite precipitation. The progressive dolomitization of these burrowed sediments could have propagated the dolomitizing fronts and extended into ambient limestones, leading to the development of extensive dolomites. This dolomitization process can improve the petrophysical properties (porosity and permeability) and the potential as hydrocarbon reservoirs during the emplacement of hydrocarbons from underlying source rocks of the Cambrian to Lower Ordovician.
U-Pb ages and europium anomalies of detrital zircons from sediments in the West Kunlun Orogenic Belt: implications for the Proto-Tethys Ocean evolution
Yinggang Zhang, Xizhu Yao, Jin Wang, Wenqing Pan, Yongquan Chen, Baoshou Zhang, Tao Yang
 doi: 10.1007/s12583-022-1671-8
[Abstract](249) [PDF 5722KB](37)
The ocean crust remnants of the Proto-Tethys were preserved as the Kudi ophiolites in the West Kunlun Orogenic Belt (WKOB), and its evolutionary history was mainly constructed by research on igneous or metamorphic rocks in the WKOB. Sedimentary rocks in the WKOB received little attention in the past; however, they could provide important constraints on the evolution of the oceanic lithosphere. Here, a series of shales and greywackes found in the Kudi area of WKOB were studied to constrain their depositional ages and explore their significance in the evolution of the Proto-Tethys oceanic crust. U-Pb dating and europium anomaly (Eu/Eu*) were analyzed for detrital zircons from greywackes interlayers, while bulk rare earth elements and yttrium (REY) of the shales were measured. Detrital zircons U-Pb ages yielded a maximum depositional age of 436 Ma for the greywackes and black shales, while the REY distribution patterns of the black shales are similar to those of the Tarim Ordovician Saergan shales. Accordingly, the studied WKOB black shales were deposited in the Proto-Tethys Ocean during the Late Ordovician-Early Silurian period. The maximum depositional age at 436 Ma may represent a minimum closure time of the Proto-Tethys Ocean, which is also supported by the absence of increases in Eu/Eu* values during the Late Ordovician-Early Silurian. Besides, our Eu/Eu* values in detrital zircons indicate diminished orogenesis during the Archean to Mesoproterozoic, subduction-related accretion at the margins of the supercontinent Rodinia during the Neoproterozoic.
Fe-Ti oxide mineralization in the XV intrusion, Bafq mining district, Central Iran: insights from mineralogy, mineral chemistry and S isotopic data
Sakine Amraei, Majid Ghasemi Siani, Mohammad Yazdi, Liang Qiu, Bertrand Moine, Minghua Ren
 doi: 10.1007/s12583-022-1675-4
[Abstract](103) [PDF 5984KB](8)
The mafic-ultramafic intrusion in the XV anomaly area, which contains magmatic Fe-Ti oxide-(P) ore, is located in the Bafq mining district in the Central Iran. It consists of cumulate and layered Fe-Ti-bearing gabbros and pyroxenites. The mineral assemblages include clinopyroxene, Fe-Ti oxides, plagioclase, amphibole, apatite and sulfides (pyrite and chalcopyrite). The Fe-Ti oxides mainly consist of magnetite-titanomagnetite and ilmenite, which occur as disseminated, intergrowth, lamellae (trellis and sandwich textures) and inclusions. Magnetite in the gabbroic rocks is from the near end-member of Fe3O4 (<1 wt. % TiO2) to titanomagnetite containing up to 8 wt. % TiO2 (about 3.73 to 26.84 % Ulvospinel (XUsp)). Magnetite in pyroxenite rocks is characterized with TiO2 range from 0.46 to 3.14 wt. % (XUsp varied from 1.76 to 10.46 %). The abundances of V2O3 range from 0.03 to 1.29 and 0.24 to 1.00 wt. % for gabbro and pyroxenite, respectively. XUsp contents of magnetite show insignificant correlations with Al2O3 and MgO. The average XIlm in the ilmenite of gabbro is 92 %, whereas it is 90.37 % in the pyroxenite rocks. The MgO and V2O3 contents show a slightly positive correlation with TiO2 in ilmenite. The composition of clinopyroxenes in gabbro and pyroxenite rocks fall in the diopside to augite field with Mg# ranging from 67 to 98 and 74 to 96, respectively. In both rock types, amphiboles are mainly pargasite and rarely actinolite. Plagioclase in pyroxenite rocks are clustered in the labradorite to andesine fields with a compositional ranges of An46-69 and in gabboic rocks fall in two fields with compositional ranges of albite with An0.65-5.95 and labradorite with An50-63. The δ 34S isotopic values cover a limited range from +3.15 ‰ to +4.10 ‰ V-CDT consistent with magmatic origin. Fe-Ti mineralization are formed in two stages, minor inclusions of Fe–Ti oxide minerals in the pyroxene and plagioclase crystallized in the early magmatic stage, whereas interstitial oxides formed by fractional crystallization processes that accumulated by gravitational settling in the later stage as intercumulus phase. Gravitational settling process is supported by the observation of decreasing the amount of Fe-Ti oxides from Fe-Ti oxide- rich pyroxenite to weak mineralized gabbro (base to top). The high contents of H2O, phosphorate and high initial Ti-Fe in parental magma are the crucial factors controlling the Fe-Ti oxides enrichment and mineralization.
monitoring multi-temporal changes of lakes on the tibetan plateau using multi-source remote sensing data from 1992 to 2019: a case study of lake zhari namco
juan wu, chang-qing ke, yu cai, zheng duan
 doi: 10.1007/s12583-022-1639-8
[Abstract](166) [PDF 7604KB](13)
lake level, area and volume are sensitive indicators of climate change. at present, many studies have focused on the interannual water balance of lakes, but lake level and area can change remarkably with seasons, especially for lakes with seasonal ice cover. zhari namco, a seasonal frozen lake, was selected as an example to investigate its seasonal water balance. multi-source altimetry and landsat data were used to obtain the seasonal lake level and area from 1992 to 2019, and seasonal lake volume variations were also estimated. the results indicated the average lake level, area and volume in autumn were the largest. the lake level, area, and volume experienced three turning points approximately in 2000, 2010, and 2016, and showed an overall increasing trend from 1992 to 2019, with slopes of 0.15 m/year, 2.17 km2/year, and 0.14 km3/year, respectively. the lake area expanded significantly in autumn, which was related to the abundant precipitation. delay time of land surface runoff, increased temperature, and evaporation may be the reason for the low lake level and volume in summer. the precipitation was the dominant factor of water balance, which explained 62.09%, 62.43%, and 62.10% of the variations in lake level, area, and volume, respectively.
stochastic modeling of folded structures in scarce data scenarios using transiogram with locally varying anisotropy
yabo zhao, weihua hua, guoxiong chen, liang dong, zhipeng liu, xiuguo liu
 doi: 10.1007/s12583-022-1646-9
[Abstract](140) [PDF 3963KB](4)
sampling is usually scarce in geological modeling, and hence, complex and continuous geological phenomena are difficult to simulate when anisotropy changes locally. the current study aimed to present a method for modeling folded structures using transiogram with locally varying anisotropy in scarce data scenarios. based on the direction fields of locally varying anisotropy, a pathline-based algorithm was proposed to simulate the folds that are flattened and calculate the relative position of any two random points thereafter. compared to the traditional two-point spatial continuity measures (such as the variogram), the locally varying anisotropy transiogram could not only describe the high order markovian of the spatial distribution of geological bodies, but also do so with explicable physical implication. the report revealed that the locally varying anisotropy transiogram of horizontal strata can be directly obtained if the stratigraphic sequence and stratum thickness are known. in the case study, only one geological map was used in a real complex-fold area to successfully simulate the 3-d stratigraphic model.
gastropod fauna of the zuodeng permian-triassic boundary section in the nanpanjiang basin and its geometric-based morphological disparity analysis
xin sun, li tian, xincheng qiu, kaiping guan, erik tihelka, haijun song, jinnan tong, hao yang
 doi: 10.1007/s12583-022-1645-x
[Abstract](90) [PDF 4539KB](7)
gastropods, as one of the most common invertebrates in shallow marine environments, were heavily impacted by the permian-triassic mass extinction (ptme), with severe loss of diversity and remarkable dwarfism of body size. here, we report a new gastropod fauna from the permian‒triassic carbonates of zuodeng, guangxi province, south china. five species belonging to five genera and two indeterminate taxa are identified. the zuodeng fauna is dominated by paleozoic holdover taxa, including holopea teres, protostylus sp., and wannerispira shangganensis although most of them are found in the basal triassic microbialites. three gastropod communities have been recognized by cluster analysis. further morphological analyses show that the changing pattern of disparity, with diversity decreasing from community ⅱ to ⅲ, fits the interior-reduction model. in addition, the morphospace of community in microbialites is higher than those in non-microbialite bearing beds at zuodeng, shedding new light on the ecological role of microbialites during the permian-triassic environmental stress.
susceptibility mapping of ground collapse caused by anthropogenic activities
zhongmin mao, yuyong jiao, fei tan, xin qi, cong zeng
 doi: 10.1007/s12583-022-1644-y
[Abstract](80) [PDF 4967KB](3)
frequent ground collapses resulted by anthropogenic activities occur due to rapid urbanization. accurate susceptibility mapping is critical for disaster prevention and control. in this study, 1198 ground collapse cases were collected from 2017 to 2020 in shenzhen. after multicollinearity testing, eight effective factors (elevation, relief, clay proportion, average annual precipitation, distance from water, land use type, building density, and road density) were selected to construct an evaluation index system. ground collapse susceptibility was analyzed and mapped using the normalized frequency ratio (nfr), logistic regression (lr), and nfr-lr coupling models. finally, the rationality and performance of the three models were compared using the frequency ratio (fr) and receiver operating characteristic (roc) curve, respectively. all three models could effectively evaluate the ground collapse susceptibility (area under the roc curve (auc) > 0.7), though the result of nfr-lr model was more rational and had the highest performance (auc = 0.791) among the three models. shenzhen possessed ground collapses mainly in built-up areas, the greater the intensity of anthropogenic activity in a location, the higher the likelihood of a disaster. the high and very high susceptibility zones covered a total area of 546.76 km2 and involved the nanshan, luohu, and futian districts, as well as some areas of the baoan, guangming, and longgang districts.
Protoconodonts and Paraconodonts from the Machari Formation (upper Series 3 and Furongian) in the Eodungol Section, Yeongwol, Korea
Byung-su LEE
[Abstract](255) [PDF 2509KB](26)
The Machari Formation ranges from the “upper Series 3” (Middle Cambrian) to Furongian (Upper Cambrian) in the Yeongwol area, Korea. It has been known to yield relatively diverse invertebrate fossils. Particularly trilobite biozones of the formation have been well defined. On the other hand, little has hitherto been studied on conodont microfossils for the formation. This paper reports a diverse and well preserved protoconodonts and paraconodonts of Series 3 from the formation in the Eodungol section, exposed along a southern mountain trail of Mt. Sambangsan, Yeongwol, Korea. Five of the thirteen samples collected for conodont contain a rich protoconodont and paraconodont assemblage and numerous shelly fossils including trilobites, brachiopods, sponge spicules, hyolithids and incertae sedis. Sample Eo5 is extremely fossiliferous (465 elements, 96.5 % of total collection), and the most abundant species was Phakelodus elongatus (236 elements, 62 % of the Eo5 collection). The preservation is relatively good, but some specimens are corroded and fragmentary. Some of protoconodonts are exfoliated. Relatively larger ones were commonly preserved as phosphatized internal molds, particularly in specimens of Furnishina bigeminata, Furnishina leei n. sp., Muellerodus pomeranensis, Nogamiconus sinensis and westergaardodids. Phakelodids were commonly preserved as clusters. Among twenty species referable to nine genera, Furnishina bigeminata, Furnishina leei n. sp., Nogamiconus sinensis, Huayuanodontus tricornis, Proscandodus obliquus, and Westergaardodina grandidens were previously undescribed species in Korea. This assemblage is named herein as the Westergaardodina matsushitai Zone, which is new biozonal name replacing the old one i.e., Gapparodus bisulcatus-Westergaardodina matsushitai-Westergaardodina moessebergensis Assemblage. The W. matsushitai Zone corresponds to the Lejopyge armata trilobite Zone, and is well correlated with the upper Series 3 conodont biozones of the Westergaardodina matsushitai-Westergaardodina grandidens Zone of South China, and the Westergaardodina matsushitai Zone of North China, respectively. The present data allow a useful correlation to China and Baltica in relation to new subdivision of the Cambrian. Furnishina leei n. sp. is newly described.
knowledge graph for identifying geological disasters by integrating computer vision with ontology
qinjun qiu, zhong xie, die zhang, kai ma, liufeng tao, yongjian tan, zhipeng zhang, baode jiang
 doi: 10.1007/s12583-022-1641-1
[Abstract](126) [PDF 1946KB](40)
the occurrence of geological disasters can have a large impact on urban safety. protecting people's safety is the most important concern when disasters occur. safety improvement requires a large amount of comprehensive and representative risk analysis and a large collection of information related to geological hazards, including unstructured knowledge and experience. to address the relevant information and support safety risk analysis, a geological hazard knowledge graph is developed automatically based on computer vision and domain-geoscience ontology to identify geological hazards from input images while obeying safety rules and regulations, even when affected by changes. in the implementation of the knowledge graph, we design an ontology schema of geological disasters based on a top-down approach, and by organizing knowledge as a logical semantic expression, it can be shared using ontology technologies and therefore enable semantic interoperability. computer vision approaches are then used to automatically detect a set of entities and attributes, using the data from input images, and object types and their attributes are identified so that they can be stored in neo4j for reasoning and searching. finally, a reasoning model for geological hazard identification was developed using the neo4j database to create nodes, relationships, and their properties for modeling, and geological hazards in the images can be automatically identified by searching the neo4j database. an application on geological hazard is presented. the results show the effectiveness of the proposed approach in terms of identifying possible potential hazards in geological hazards and assisting in formulating targeted preventive measures.
Uranium Isotope Variations (234U/238U and 238U/235U) and Behavior of U-Pb Isotope System in the Vershinnoe SandstoneType Uranium Deposit, Vitim Uranium Ore District, Russia
V. N. Golubev, I. V. Chernyshev, B. T. Kochkin, N. N. Tarasov, G. V. Ochirova, A. V. Chugaev
[Abstract](24) [PDF 5507KB](14)
The U-Pb isotope system and uranium isotope composition (235U/238U and 234U/238U) were studied in a number of samples from the vertical section of the uranium ore body at the Vershinnoe sandstone-type deposit, Vitim uranium ore district, Russia. These parameters were determined to broadly vary. Deviations of the 234U/238U ratio from the equilibrium value indicate that the uranium ore was not completely conserved during the postore stage, and uranium was determined to continue mi‐grating at the deposit. Comparison of the U-Pb isotope age value and 234U/238U isotope ratio provides an insight into the migrate direction of uranium in the ore body. The broad variations (137.377–137.772) in the 238U/235U ratio over the vertical section of the ore body can be explained by the different settings of the samples relative to the ore deposition front and changes in the redox conditions when this front shifted. The fact that the δ238U and K234/238 values are correlated indicates that the transfer of the 234U iso‐tope into the aqueous phase may have been coupled with isotope fractionation in the 238U-235U system during the postformation uranium migration within the orebody.
Association of Sandstone-Type Uranium Mineralization in the Northern China with Tectonic Movements and Hydrocarbons
Yin Chen, Peisen Miao, Jianguo Li, Ruoshi Jin, Hualei Zhao, Lulu Chen, CongWang, Haoyu Yu, Xiaoru Zhang
[Abstract](77) [PDF 50719KB](23)
In the continental basins of Northern China (NC), a series of energy resources commonly co-exist in the same basin. As the three typical superimposed basins of different genesis in the NC, the Junggar, Ordos, and Songliao basins were chosen as the research objects. The favorable uraniumbearing structures are generally shown as a basin-margin slope or transition belt of uplifts with the de‐velopment of faults, which are conducive to a fluid circulation system. The Hercynian, Indosinian, and Yanshanian movements resulted in the development of uranium-rich intrusions which acted as the sig‐nificant uranium sources. The main hydrocarbon source rocks are developed in the Carboniferous, Permian, Jurassic and Cretaceous. The mature stage of source rocks is concentrated in the Jurassic–Cretaceous, followed by the multi-stage expulsion events. Influenced by the India-Eurasian collision and the subduction of the Pacific Plate, the tectonic transformation in the Late Yanshanian and Himala‐yan periods significantly influenced the sandstone-type uranium mineralization. The hydrocarbon reser‐voirs are spatially consistent with sandstone-type uranium deposits, while the hydrocarbon expulsionevents occur in sequence with sandstone-type uranium mineralization. In the periphery of the faults or the uplifts, both fluids met and formed uranium concentration. The regional tectonic movements moti‐vate the migration of hydrocarbon fluids and uranium mineralization, especially the Himalayan move‐ment.
An investigation of dislocation in olivine phenocrysts from the Hawaiian basalts
Zhuo-Yue Li, Da-Peng Wen, Yong-Feng Wang, Xiang-Wen Liu
 doi: 10.1007/s12583-020-1030-6
[Abstract](2032) [PDF 7048KB](155)
Intracrystalline distortions (like undulose extinction, dislocations, and subgrain boundaries) in olivine from naturally-deformed peridotites is generally taken as a sign of dislocation creep. However, similar features in olivine phenocrysts that were found in basaltic magmas are still not well understood. In particular, whether subgrain boundaries in olivine phenocrysts arise from plastic deformation or grain growth is still debated (In the latter case, they are essentially grain boundaries but not subgrain boundaries. Therefore, we used hereinafter subgrain-boundary-like structures instead of subgrain boundaries to name this kind of intracrystalline distortion). Here we carried out a detailed study on dislocations and subgrain-boundary-like (SG-like) structures in olivine phenocrysts from two Hawaiian basaltic lavas by means of petrographic microscopy, scanning electron microscopy, and transmission electron microscopy (TEM). Abundant and complex dislocation substructures (free dislocations, dislocation walls, and dislocation tangles) were observed in the decorated olivine grains, similar to those in olivine from peridotite xenoliths entrained by the Hawaiian basalts. The measured average dislocation density is 2.9 ± 1.3 × 1011 m-2, and is three to five orders of magnitude higher than that in laboratory-synthesized, undeformed olivine. TEM observations on samples cut across the SG-like structures by FIB (focused ion beam) demonstrated that this kind of structures is made of an array of dislocations. These observations clearly indicate that these structures are real subgrain boundaries rather than grain boundaries. These facts suggested that the observed high dislocation densities and subgrain boundaries were not resulted from crystal crystallization/growth, but were formed by plastic deformation. These deformation features do not prove that the olivine phenocrysts (and implicitly mantle xenoliths) were deformed after their capture by the basaltic magmas, but can be ascribed to a former deformation event in a dunitic cumulate, which was formed by magmatic fractionation, then plastically deformed, and finally disaggregated and captured by the basaltic magma that brought them to the surface.
Central Asia––A Global Model for the Formation of Epigenetic Deposits in a Platform Sedimentary Cover
Igor Pechenkin, Vladislav Petrov
[Abstract](11) [PDF 8469KB](6)
Metallogenic specialization of sedimentary cover in Central Asia is determined by its tec‐tonic setting that governs the hydrodynamic regime (exfiltrational or infiltrational) and as a consequence, the hydrogeochemical zonality (type of water and its gaseous and microcomponent composition). Hydro‐dynamic conditions (distribution of recharge and discharge areas) determine the direction of stratal water flow and location of mineralization resulted from the change in geochemical, thermodynamic, litholog‐ical, structural and other conditions. The exfiltrational regime suggests a dependence of the epigenetic mineralization upon the distribution and degree of preservation of hydrocarbon occurrences. Often, hy‐drocarbon matter serves as a reducing barrier and ore-concentrating factor during the formation of polymineral concentrations related to stratal oxidation zone. The supergene epigenetic ore-forming pro‐cesses are induced by the interaction between the Earth’s sedimentary cover and hydrosphere. Sedimen‐tary rocks themselves commonly serve as a source of ore materials. The ore deposition zones on geochemi‐cal barriers and ore material source are often located significantly apart from each other. The trend of these processes is determined by the position of ore-bearing depressions in large tectonic blocks.
Theoretical System of Sandstone-Type Uranium Deposits in Northern China
Ruoshi Jin, Huajian Liu, Xiaoguang Li
[Abstract](56) [PDF 19090KB](14)
Many theoretical results on sandstone-type uranium mineralization in northern China obtained by the uranium research team of the Tianjin Center of Geological Survey in recent years are presented. From the source sink system of uranium-producing basins, sedimentary environment of uranium-bearing rock series, ore-forming fluid information, evolution of tectonic events, basin forma‐tion and development, we redefine and classify uranium orebodies, redox zoning, and ore-controlling structural styles. We then systematically propose a theoretical system of sandstone-type uranium depos‐its in northern China. We conclude that sandstone-type uranium deposits in northern China are main‐ly found in sedimentary environments such as rivers, deltas, and alluvial fans in the Mesozoic and Cenozoic lowstand systems tract and in gray sandstone layers in the vertical redox zoning. The orebodies are controlled by the tectonic slope belt, which is in the shape of a strip on the plane, and spreads in a layer or plate on the section. Vertical (ups and downs) tectonic movement triggers large-scale phreatic flow in the basin, which is the real driving force for controlling the ore-forming fluid. The theoretical system of sandstone-type uranium deposits in northern China should be based on global tectonic move‐ment and environmental changes and take into account factors such as basins as a unit to study miner‐alization background, ore concentration areas as objects to study mineralization, and the correlation between regional tectonic movement and metallogenic process as a breakthrough point to study tecton‐ic events and metallogenic events. It should also be based on different basin types to establish metallo‐genic models. The innovative research results and ideas are summarized with the aim of promoting the continuous improvement of sandstone-type uranium mineralization theory in northern China.
U-Blacks Mineralization in Sandstone Uranium Deposits
Olga A. Doynikova
[Abstract](20) [PDF 18000KB](9)
Ores of infiltration sandstone-hosted uranium deposits in the sedimentary cover are ubiquitous composed of dispersed soot powder mineralization of black, brownish-black colour. Longterm studies of such loose U-ores by analytical transmission electron microscopy (ATEM) proved their polymineral nature. Uranium blacks are composed by at least three different U-mineral forms: oxide (uraninite), silicate (coffinite) and phosphate (ningyoite) which are present in various proportions of ore compositions. Such high dispersed friable uranium formations are difficult to diagnose by tradition‐al mineralogical methods (optical, XRD, IR and X-ray spectroscopy, etc.) which analyze total sample composition (phases mixture); their results characterize the dominant sample phase, omitting both sharply subordinate and X-ray amorphous phases. All research results are based on ATEM methods (SAED+EDS), which are optimal for crystallochemical diagnostics in the mineralogical study of such uranium ores. The article presents the diagnostic characteristics under electron microscope (EM) of uranous minerals from different sandstone deposits with their origin being discussed.
Classification of Sandstone-Related Uranium Deposits
Michel Cuney, Julien Mercadier, Christophe Bonnetti
[Abstract](100) [PDF 1583KB](18)
Sandstone type deposits are the most common type of uranium deposits in the world. A large variety of sub-types have been defined, based either on the morphology of the deposits (e.g., tabu‐lar, roll front, etc), or on the sedimentological setting (e.g., paleovalley, paleochannel, unconformity), or on tectonic or lithologic controls (e.g., tectonolithologic, mafic dykes/sills), or still on a variety of others characteristics (phreatic oxidation type, interlayer permeable type, multi-element stratabound infiltra‐tional, solution front limb deposit, humate type, etc.), reflecting the diversity of the characteristics of these deposits, but making it difficult to have a clear overview of these deposits. Moreover, uranium de‐posits occurring in the same sedimentological setting (e.g., paleochannel), presenting similar morpholo‐gies (e.g., tabular), may result from different genetic mechanisms and thus can be misleading for explora‐tion strategies. The aim of the present paper is to propose a new view on sandstone-related uranium de-posits combining both genetic and descriptive criteria. The dual view is indeed of primordial importance because all the critical characteristics of each deposit type, not limited to the morphology/geometry of the ore bodies and their relationships with depositional environments of the sandstone, have to be taken into account to propose a comprehensive classification of uranium deposits. In this respect, several key ore-forming processes, like the physical-chemical characteristics of the mineralizing fluid, have to be used to integrate genetic aspects in the classification. Although a succession of concentration steps, potentially temporally-disconnected, are involved in the genesis of some uranium mineralization, the classification here proposed will focus on the main mechanisms responsible for the formation and/or the location of ore deposits. The objective of this paper is also to propose a robust and widely usable ter‐minology to define and categorize sandstone uranium deposits, considering the diversity of their origin and morphologies, and will be primarily based on the temperature of the mineralizing fluid considered as having played the critical role in the transportation of the uranium, starting from synsedimentary ura‐nium deposits to those related to higher temperature fluids.
2023, 34(4): .  
[Abstract](56) [PDF 33890KB](28)
2023, 34(4): .  
[Abstract](36) [PDF 359KB](14)
Special Issue on Unconventional Oil-Gas Innovation and New Energy Development
Guest Editors: Caineng Zou, Wanzhong Shi and Detian Yan
Theory, Technology and Practice of Unconventional Petroleum Geology
Caineng Zou, Zhi Yang, Guosheng Zhang, Rukai Zhu, Shizhen Tao, Xuanjun Yuan, Lianhua Hou, Dazhong Dong, Qiulin Guo, Yan Song, Qiquan Ran, Zhen Qiu, Songtao Wu, Feng Ma, Bin Bai, Lan Wang, Bo Xiong, Songqi Pan, Hanlin Liu, Xiaoni Wang
2023, 34(4): 951-965.   doi: 10.1007/s12583-023-2000-8
[Abstract](158) [FullText HTML](158) [PDF 1533KB](54)
A New Method for Converting T2 Spectrum into Pore Radius
Fan Zhang, Zhenxue Jiang, Yuanhao Zhang, Bin Hu, Zaiquan Yang, Yuhua Yang, Xianglu Tang, Hanmin Xiao, Lin Zhu, Yunhao Han
2023, 34(4): 966-974.   doi: 10.1007/s12583-021-1576-y
[Abstract](110) [FullText HTML](110) [PDF 1309KB](38)

In this paper, a new method for converting the T2 (relaxation time) of NMR (nuclear magnetic resonance) into the pore radius is proposed. Combined with NMR and centrifugation experiments, the relationship between pore radius and T2 of the sample was established. The results show that the new method is more reasonable than the traditional method. When the sample was denser and the mercury saturation was lower, the pore distribution curve was obtained by traditional method had a worse agreement with mercury injection experiment, while pore distribution curve of the new method had a better agreement with the mercury injection curve, which reflected the greater advantage of the new method as the reservoir becomes denser. The new method can obtain all the pore information in the sample. The results show that the pores in tight sandstone are mainly consisted with mesopore and macropore, and the connectivity of macropore is better than that of mesopore. The new method can effectively characterize the full pore distribution and the seepage characteristics in different pores interval of tight reservoirs, which had a great significance to evaluate the recoverable resources of tight reservoir.

Development Strategy and Countermeasures of China's CBM Industry under the Goal of "Carbon Peak and Neutrality"
Fengyin Xu, Xia Yan, Fenglin Wang, Xinyuan Ma, Jian Yun, Hongna Wang, Borui Xu, Shuangyuan Zhang, Delei Mao
2023, 34(4): 975-984.   doi: 10.1007/s12583-022-1647-8
[Abstract](619) [FullText HTML](377) [PDF 2123KB](37)

China's coalbed methane (CBM) industry is in an extremely important "climbing period" and "strategic opportunity period", which can be generally characterized by "three low and one small": low degree of exploration and development, low adaptability of main technology, low return on investment and small development scale. Under the "carbon peak and neutrality" background, the development status of CBM industry is systematically combed. The resources, technology, management problems and reasons are analyzed. Strategies and countermeasures to accelerate the industrial development are put forward according to the factors such as efficient development of resources, major technical breakthrough, talent team training, policy formulation and implementation, return on investment and so on. The existing problems are as follows: (a) The overall occurrence conditions in China are complicated and the development is difficult compared with the other countries. (b) The research precision accuracy of CBM resource conditions is not enough. (c) The adaptability of technology is poor. (d) The management mode is not suitable. In view of these problems, this paper puts forward the "two steps" development strategy and the technical and management countermeasures of "five in one". The corresponding "five in one" technology and management countermeasures are the formulation and implementation of relevant safeguard measures in accordance with the principle of collaborative innovation in five aspects: resources, technology, talents, policies and investment. Through the above measures, the dream and grand blueprint of CBM industry shall be realized.

In-situ Fluid Phase Variation along the Thermal Maturation Gradient in Shale Petroleum Systems and Its Impact on Well Production Performance
Qianyou Wang, Wei Yang, Yaohua Li, Zhenxue Jiang, Ming Wen, Rusi Zuo, Xin Wang, Zixin Xue, Yaohua Wang
2023, 34(4): 985-1001.   doi: 10.1007/s12583-022-1693-2
[Abstract](196) [FullText HTML](192) [PDF 11314KB](32)

In-situ fluid phase behavior is important in determining hydrocarbon contents and the multiphase flow through shale reservoirs. The gas-to-oil ratio (GOR) has been recognized as a critical indicator of fluid types. However, little is known about the impact of fluid phase variation across the thermal maturity on shale oil/gas production (e.g., estimated ultimate recovery, EUR). According to the specific gravity ratio of oil/gas, the producing GOR was converted and normalized into a mass fraction of gas in total hydrocarbons (MGOR) to compare North American shale oil/gas plays with Chinese shale oil and hybrid gas-condensate plays. A correlation between MGOR, the fluid phases, and production data was established to identify five phase stages of flow. MGOR varies systematically with the different production zones, which shows promise in rapidly indicating the well production performance and high production stages of shale oil/gas plays. The hybrid shale gas condensate index, Tmax, and total gas contents were integrated to present the fluid types and maturity of shale gas-condensates, which indicates fluid phase and production variation across thermal evolution. The results offer a unique perspective on the shale oil reservoir producibility based on the impact of GOR on fluid phases and EUR from the dominant global oil/gas plays.

Gas-in-Place (GIP) Variation and Main Controlling Factors for the Deep Wufeng-Longmaxi Shales in the Luzhou Area of the Southern Sichuan Basin, China
Wei Wu, Peng Cheng, Shenyang Liu, Chao Luo, Haifeng Gai, Haitao Gao, Qin Zhou, Tengfei Li, Kesu Zhong, Hui Tian
2023, 34(4): 1002-1011.   doi: 10.1007/s12583-021-1593-x
[Abstract](60) [FullText HTML](60) [PDF 6239KB](4)

The Wufeng-Longmaxi Formation shales with burial depths > 3 500 m in the southern Sichuan Basin are believed to have large shale gas potentials. However, the reservoir properties and gas-in-place (GIP) contents of these shales exhibit variations across different sublayers. In this study, a set of Wufeng-Longmaxi shales with burial depths of 4 000–4 200 m was derived from the Well Y101H2 in the Luzhou area, and the differences in geological and geochemical characteristics, porosity, water saturation and GIP content of various sublayer shales were investigated. The results indicate that the TOC content and effective porosity of the upper (LMX1-4) and lower (LMX1-3) sublayer shales of the first member of the Longmaxi Formation are better than those of the Wufeng Formation (WF) shales, which results in the LMX1-4 and LMX1-3 shales having higher GIP contents than the WF shales. The GIP contents of the LMX1-3 shales are higher than those of the LMX1-4 shales, and this is likely because the organic matter of the LMX1-3 shales had more aquatic organisms and was preserved in a stronger reductive environment, which leads to a stronger gas generation potential. In contrast to the middle-shallow LMX1-4 shales in the Sichuan Basin, the deep LMX1-4 shales in the Luzhou area have advantageous reservoir properties and GIP contents, and thus it is promising to synchronously exploit the deep LMX1-4 and LMX1-3 shales in some regions of the southern Sichuan Basin.

Gas Generation from Coal and Coal-Measure Mudstone Source Rocks of the Xujiahe Formation in the Western Sichuan Depression, Sichuan Basin
Zijin Wu, Tengfei Li, Sui Ji, Qin Zhou, Hui Tian
2023, 34(4): 1012-1025.   doi: 10.1007/s12583-022-1627-z
[Abstract](41) [FullText HTML](41) [PDF 932KB](10)

The Triassic and Jurassic tight sandstone gas in the western Sichuan depression, Sichuan Basin has attracted much attention in recent years, and the Upper Triassic coal-bearing Xujiahe Formation is believed to be the major source rock. However, there are relatively few studies on the carbon isotopic heterogeneity of methane generated from coal-measure source rocks and the origin of the natural gases in Xinchang Gas Field is still controversial. In this study, one coal-measure mudstone sample and one coal sample of the Xujiahe Formation in western Sichuan Basin were selected for gold tube pyrolysis experiment to determine their gas generation characteristics. Geological extrapolation of gas generation and methane carbon isotope fractionation parameters reveals that the main gas generation stage of Xujiahe Formation ranges from Late Jurassic to Cretaceous in the Xinchang Gas Field. The natural gas in the 5th member of Xujiahe Formation in Xinchang Gas Field is mainly derived from the 5th member of Xujiahe Formation itself, i.e., self-generation and self-reservoir, however, the gas in the Jurassic gas pools is mainly derived from the source rocks of the 3rd member of Xujiahe Formation rather than the 5th member of Xujiahe Formation.

Comparison of Formation Conditions of Source Rocks of Fengcheng and Lucaogou Formations in the Junggar Basin, NW China: Implications for Organic Matter Enrichment and Hydrocarbon Potential
Shiju Liu, Gang Gao, Wenzhe Gang, Baoli Xiang, Ming Wang, Chengyun Wang
2023, 34(4): 1026-1040.   doi: 10.1007/s12583-021-1566-0
[Abstract](66) [FullText HTML](66) [PDF 35458KB](16)

Shales in the Carboniferous–Permian Fengcheng (FC) and Lucaogou (LCG) formations in Junggar Basin are important organic rich rocks containing significant oil resources. To evaluate the difference in sedimentary environment conditions and hydrocarbon-generating potential between the FC and LCG formations. Total organic carbon (TOC), Rock-Eval pyrolysis, solvent extraction, column fractionation, stable carbon isotope, gas chromatography-mass spectrometry (GC-MS) of saturated hydrocarbons and organic petrology from the source rocks of FC and LCG formations. were analyzed. The biomarker composition indicates that during the deposition of FC, LCG-1 to LCG-2, the sedimentary environment for the source rock formations changed with gradual decrease of salinity, from anoxic to dyoxic/suboxic in redox conditions, and from strong stratification to weakened stratification of water. The FC Formation source rock, with main telalginite (planktonic green algae), archaebacteria and minor terrestrial organic matter, deposited in the environment characterized by high salinity and strongly reducing condition. Its TOC content is relatively low with a high original hydrocarbon-generating potential of unit organic material. The LCG Formation source rock deposited in the environment with low salinity and large variations, the organic matter is mainly sourced from telalginite (planktonic green algae), lamalginite, bacteria and higher plants, resulting in strong heterogeneity of the source rock. The abundance of TOC is high, but the original hydrocarbon generation potential of unit organic matter is lower than that of FC Formation. The results provide a geochemical basis for further study of saline-brackish water sedimentary environment shales in the Junggar Basin.

Heavy Oil Reservoir Seismic Characteristics during Thermal Production: A Case Study
Yi Zhang, Yun Wang, Hemin Yuan, Jiapeng Liu
2023, 34(4): 1041-1052.   doi: 10.1007/s12583-022-1618-0
[Abstract](57) [FullText HTML](57) [PDF 5617KB](7)

Most production methods of heavy oil involve thermal production. However, it is challenging to delineate the thermal-affected zone due to complex reservoir conditions. With steam injected, the heavy oil viscosity drops; the reservoir density and velocity decrease accordingly, causing changes to seismic impedance. Moreover, the oil-and-water viscosity ratio and permeability show the difference with changing temperature, indicating that the reservoir's ability to transmit seismic waves would also be temperature-dependent. Therefore, the seismic responses and attenuation characteristics of the steam chamber can be helpful to monitor the steam-affected zone. We introduce an improved viscoelastic model to approximate the heavy oil reservoir during thermal production, and use the frequency-space domain finite difference algorithm to simulate the seismic wave-fields. Numerical results demonstrate that this model is applicable to a wide temperature range, and can effectively reveal the seismic characteristics of the steam chamber. Through analyzing the propagation differences of seismic waves under different temperatures, it is concluded that the attenuation coefficient, root-mean-square amplitude difference and amplitude ratio of PP-wave and PS-wave under different conditions can reveal the temperature variation in the steam chamber, with which it is possible to detect the steam chamber spatial distribution.

Pyrite Concretions in the Lower Cambrian Niutitang Formation, South China: Response to Hydrothermal Activity
Zixuan Liu, Detian Yan, Xing Niu
2023, 34(4): 1053-1067.   doi: 10.1007/s12583-023-1821-7
[Abstract](58) [FullText HTML](58) [PDF 22729KB](9)

The Early Cambrian Niutitang Formation is characterized by wide distribution of black shales on Yangtze Block, South China. Here we have reported the pyrite concretions in the bottom of the Niutitang Formation deposited in the slope-basin environment of Yangtze Block. The pyrite concretion was mainly composed of pyrite associated with hydrothermal minerals (barite, hyalophane, tetrahedrite), followed by quartz and organic matter. Trace elements Mo and U displayed significant enrichment (enrichment factors > 10), indicating the euxinic bottom water condition. Cu, Ni, and excess Ba concentrations were relatively high, denoting high primary productivity. In-situ sulfur isotope compositions of pyrite concretions δ34Spy) showed little variations (13.2‰–19.4‰) and small fractionations compared to coeval seawater δ34Sso4. Petrological and geochemical analyses indicated the pyrite concretions were formed in the sediment-water interface during the early diagenesis, with H2S diffusing from the euxinic water, and influenced by hydrothermal activity leading to the coexistence of barite, hyalophane, and tetrahedrite. These results imply euxinic bottom water featured by high primary productivity and increasing riverine flux of sulfate from chemical weathering during the Early Cambrian.

Quantitative Inversion of REEs in Ion-Adsorbed Rare Earth Ores from the Liutang Area (South China), Based on Measured Hyperspectral Data
Gong Cheng, Hongrui Zhang, Huan Li, Xiaoqing Deng, Safiyanu Muhammad Elatikpo, Jiaxuan Li, Zhenguang Hu, Guangqiang Li
2023, 34(4): 1068-1082.   doi: 10.1007/s12583-021-1504-1
[Abstract](30) [FullText HTML](30) [PDF 9276KB](4)

Rare earth minerals are important strategic resources to economic development all over the world. In this study, multiple linear regression and back propagation (BP) neural network methods are used to invert the contents of ion adsorbed rare earth elements (REEs) and exploring the feasibility of quantitative inversion of REEs through measured hyperspectral data in Liutang rare earth mines, South China. The result shows that the spectral curve of the rare earth ore samples has obvious absorption characteristics around 390, 930, 1 400, 1 900 and 2 200 nm, and continuum removal and the 1st derivative treatment can highlight the absorption characteristics. The modeling accuracies of BP neural network are higher than that of multiple linear regression model. The BP neural network model of the 1st derivative data in 400–1 000 nm bands has the best inversion result of the total content of REEs, R2 reaches 0.98, the ratio of the performance to deviation (RPD) is larger than 3.0. The quantitative inversion model of each REE (except for Ce) has high precision, R2 is greater than 0.90 and RPD is greater than 3.0. The results indicate that quantitative inversion of REEs using measured spectra not only has great potential and feasibility in the exploration of rare earth minerals, but also provides a rapid test method for the content of ion-adsorbed rare earth elements.

Source Analysis of Lithium Deposit in Dong-Xi-Taijinaier Salt Lake of Qaidam Basin, Qinghai-Tibet Plateau
Jibin Han, Hongchen Jiang, Jiubo Liu, Jianxin Xu, Wenhua Han, Haiyun Zhang
2023, 34(4): 1083-1094.   doi: 10.1007/s12583-022-1802-2
[Abstract](53) [FullText HTML](53) [PDF 4918KB](5)

The Dong-Xi-Taijinaier Salt Lake (DXTSL) of Qaidam Basin is known as one of rich lithium reserves in China. However, the source of lithium deposits in this region remains unclear. The hydrochemistry and lithium isotopes (δ7Li) of water and solid samples along the Nalenggele River catchment were studied in combination with rock leaching experiments. The results showed the hot springs in the upstream contained high content of lithium and ratio of Li × 1 000/total dissolved solids (1.5–3.5), but the lower δ7Li values (4.33‰–11.59‰), meaning that it is one important lithium sources. The leaching experiments by the rich-lithium volcanic rocks (average content of 474.7 mg/kg) showed that under temperature of 20–80 ℃ and long time duration (24–96 h), the concentration of lithium released by leaching of the sampled volcanic rocks increased from 0.58 to 1.49 mg/L, with the leaching rate decreasing from 0.024 to 0.015 mg/(L·h) and the corresponding lithium release rate increasing from 29% to 74%. Calculation based on water-salt balance showed that the total amount of lithium contribution from hydrothermal fluids and volcanic rock weathering is about 4.99 and 0.29 Mt since 13.1 ka, respectively. Therefore, hot springs and leaching of volcanic rocks are main contributors to lithium deposit in DXTSL.

Syndepositional Fault Control on Sandbody Distribution at Two Eocene Confluence Deltas in the Dongying Depression, Bohai Bay Basin (Eastern China)
Renchao Yang, Yang Li, Aiping Fan, Nils Lenhardt, Shuvabrata De, Jie Chen
2023, 34(4): 1095-1111.   doi: 10.1007/s12583-022-1710-5
[Abstract](47) [FullText HTML](47) [PDF 86453KB](8)

The prediction of sandstone distribution is the main target for hydrocarbon exploration and petroleum reservoir engineering, especially in a rift basin with a complex geological setting. During the Middle Eocene, the Dongying and Yong'an deltas converged in the Dongying depression of the Bohai Bay Basin, eastern China. So far, studies on the control of the existing syndepositional faults on the deltaic sandbodies of the two confluence deltas have been largely neglected. In this contribution, the sedimentary characteristics and spatial distribution of the two deltas, converging in the Dongying depression, were determined. In addition, the morphodynamic controlling factors of the deposits of the two deltas were identified based on core examination, log analysis, and seismic data analysis. During delta progradation, the sandbodies of the initially separated deltas were affected by the development of syndepositional tensional faults, which eventually also influenced the distribution of the sandstone reservoirs. The results of this study can not only be applied to petroleum reservoir engineering but also provide important new information for the studies on delta sandbody all over the world.

U-Pb Zircon Ages and Geochemistry of the Metasedimentary Rocks from the Foping Area in the South Qinling Belt: Evidence for Early Devonian Amalgamation between North China and South China Blocks
Ruiying Zhang, Wenhao Ao, Yan Zhao
2023, 34(4): 1112-1127.   doi: 10.1007/s12583-022-1608-2
[Abstract](56) [FullText HTML](56) [PDF 17059KB](17)

The provenance and tectonic implications of Late Paleozoic sedimentary rocks in the South Qinling Belt (SQB) provide important clues for understanding the timing and mechanism of the collision between North China Block (NCB) and South China Block (SCB). Here we report new LA-ICP-MS zircon U-Pb ages and geochemical composition of metasedimentary rocks from the Foping area in the SQB. The results indicate that the depositional age of the Wenquan Group can be limited to the Early Devonian by the youngest U-Pb age of 398 Ma, whereas those of the quartz schist from the Changjiaoba Group could be constrained after the Carboniferous by the youngest 206Pb/238U peak age of 306 Ma. Therefore, much of the previously-assumed "Neoarchaean or Paleoproterozoic" strata, including the Wenquan and Changjiaoba groups, were actually deposited in the Late Paleozoic. Based on analysis and comparison of the detrital zircon ages of the Devonian tectonic units in the SQB, we found that most prominent peak ages of detrital zircons from metasedimentary rocks in the Foping area shared similar characteristics with others. They mainly derived from the North Qinling Belt and South Qinling Belt-Yangtze Block, with a minor source probably from the North China Block, implying that the Shangdan Ocean between NCB and SCB had closed in the Early Devonian. Combined with regional geological background and geochemical data, we inferred that these Devonian strata formed in the foreland basin after the amalgamation of the North China Block and South China Block.

Neoproterozoic Diamictite of the Luoquan Formation from the North China Block and Their Implications
Peishan Sui, Weidong Sun, Nan Han, Lei Wang, Shiwen Xie, Zihang Huang, Xiaohong Wang, Hongmei Gong, Jin Liu, Jinyan Lin, Yuanyuan Xiao
2023, 34(4): 1128-1139.   doi: 10.1007/s12583-021-1550-8
[Abstract](33) [FullText HTML](33) [PDF 9458KB](6)

Glacial diamictite may provide important information on paleoenvironment and average composition of the upper continental crust (UCC). In this study, we report sedimentary facies, petrological and geochemical characteristics of Neoproterozoic diamictite from a profile of the Luoquan Formation on the southern margin of the North China Block (NCB). Upwards the sampling profile, lithostratigraphic strata vary from massive diamictite with poorly sorted carbonate gravels to laminated diamictite with small gravels of terrestrial detrital materials. Along the profile, CaO-MgO-LOI-Sr values decrease with the increase of SiO2-Al2O3-K2O contents. All these petrological and geochemical variations indicate a change from lodgement till deposition in the proximal of ice sheet to ice-rafting deposition in glacial-marine environment with less dolomite to supply their source. Together with previous studies on diamictite from other outcrops on the NCB, the deposition of Luoquan diamictite reflects that the glaciation on the NCB vanished and the ice-rafting effect weakened with glacial transgression process. In addition, significant co-variations of various elements with La and Al2O3 confirm the significant conservation of most analyzed elements during the sedimentary processes to produce diamictite.

Exhumation and Deformation of the Daba Shan Orocline as Determined from Modern River Sands Apatite Fission-Track
Jiali You, Zhao Yang, Xiaohui Shi, Chuanbo Shen, Yunpeng Dong, Bin Cheng
2023, 34(4): 1140-1149.   doi: 10.1007/s12583-022-1632-2
[Abstract](33) [FullText HTML](33) [PDF 6672KB](7)

The Daba Shan orocline is located at the northeastern margin of the Sichuan Basin and has been inferred as a foreland thrust-fold belt of the Qinling Orogen since the Late Triassic. A complete understanding of rock exhumation history is critical to elucidate how and when this typical orocline structure is developed. Detrital apatite fission-track dating of modern river sands is employed to reveal the regional exhumation history of the Daba Shan orocline. Four age peaks are identified and interpreted as the results of tectonic exhumation. Two older age peaks at ~150–140 and ~116–86 Ma are agreement with two main shortening deformation episodes of the Yanshanian Movement in the eastern China. The other two younger age peaks at ~69 and ~37 Ma support that the Daba Shan was reactivated by the Late Cretaceous to Cenozoic deformation which were likely related to the subduction of the Pacific Ocean and eastward growth of the Tibetan Plateau, respectively. It is worth noting that in contrast to the ~150–140 Ma rapid rock uplift and exhumation, the Middle Cretaceous exhumation (~116–86 Ma) shifted southward and continued to spread to southern tips of the Daba Shan. These exhumation variations in temporal and spatial allow a southward thrust deformation with piggyback style during the Yanshanian.

Prolonged Mantle Modification beneath the North China Craton: Evidence from Contrasting Mafic Dykes in Jiaodong Peninsula
Leilei Dong, Zhiming Yang, Mingchun Song
2023, 34(4): 1150-1164.   doi: 10.1007/s12583-022-1737-7
[Abstract](44) [FullText HTML](44) [PDF 4918KB](11)

The nature of lithosphere mantle beneath North China Craton (NCC) has been changed during the Mesozoic. We investigated the mafic dykes in Jiaodong to put constraint on the origin of them and reveal the mantle evolution of the NCC. Zircons from Kunyushan and Nansu mafic dykes give concordia U-Pb ages of 114.9 and 52.8 Ma, respectively. The Kunyushan mafic dyke has high MgO (~8.0 wt.%) and Cr (> 380 ppm) but lower FeO (< 10 wt.%) contents. Large ion lithophile elements (LILE) are enriched compared to primitive mantle. The εHf(t) values of zircons are between -15.0 and -20.1. All these geochemical data imply an old and enriched lithosphere mantle source. In contrast, the Nansu mafic dyke has lower concentrations of MgO (< 7.0 wt.%) and Cr (200 ppm–230 ppm) but higher FeO (> 11 wt.%) contents. The LILE and light rare earth elements (LREE) are not so strongly enriched relative to the mafic dyke from Kunyushan but display slight enrichment compared to the primitive mantle. Positive zircon εHf(t) values are obtained (from +11.7 to +19.5, with one outlier of +3.4). It is suggested that the Nansu dyke sourced from an enriched MORB mantle and was generated by fluid flux melting.

Lithospheric Equilibrium and Anisotropy around the 2021 Yangbi Ms 6.4 Earthquake in Yunnan, China
Guangyu Fu, Zhenyu Wang, Jingsong Liu, Yun Wang
2023, 34(4): 1165-1175.   doi: 10.1007/s12583-022-1607-3
[Abstract](29) [FullText HTML](29) [PDF 14500KB](1)

Using the gravity/GNSS data of 318 stations observed in 2020, this paper optimizes the Bouguer and free-air gravity anomalies around the 2021 Yangbi Ms 6.4 Earthquake, inverses the lithospheric density structure of the focal area, and obtains the distribution of isostatic additional force borne by the lithosphere. The results show that the Bouguer gravity anomaly in western Yunnan varies from -120 to -360 mGal. As a whole the anomalies are large in the north and small in the south, and the value in the source area of the 2021 Yangbi Ms 6.4 Earthquake is about -260 mGal. Significant lateral differences indicates that the crust around the great earthquake does not belong to a solid and stable tectonic unit. The lithosphere in the source area is basically in equilibrium, indicating that the occurrence of the great event is not relative to the lithospheric equilibrium, but to the differential movement of the crust in the horizontal direction. In addition, we obtain the teleseismic SKS phases of 51 stations. As a whole, the polarization direction of fast wave in western Yunnan is approximately vertical to the maximum gradient change direction of regional Bouguer gravity anomaly that reflects the change of Moho.

A New Bothriolepid Antiarch from the Middle Devonian in Luquan, Yunnan, South China and Its Stratigraphic and Biogeographic Significances
Sheng Liu, Zhaohui Pan, Min Zhu, Liantao Jia, Wenjin Zhao
2023, 34(4): 1176-1188.   doi: 10.1007/s12583-022-1775-1
[Abstract](39) [FullText HTML](39) [PDF 8455KB](2)

Chahuaqingolepis magniporus gen. et sp. nov., a new taxon of Bothriolepididae (Placodermi: Antiarcha), is described from the Middle Devonian in Luquan County, Yunnan Province, South China. The phylogenetic analysis shows that Chahuaqingolepis is the sister group of Wufengshania with the synapomorphy of the large obtected nuchal area. Together with the findings of other associated antiarchs including Dianolepis, Bothriolepis, and Hunanolepis, the new bothriolepid antiarch is assigned to the Bothriolepis sinensis-Hunanolepis fish assemblage, which characterizes the Eifelian of the Middle Devonian in South China. The fish-bearing Tanglishu Formation can be well correlated with the Tiao-majian Formation in Changsha, Shangshuanghe Formation and lower part of the Haikou Formation in Qujing, and Laohutou Formation in Shaoguan and Lechang areas. This discovery not only enriches the Middle Devonian diversity of bothriolepids, but also provides reliable paleoichthyological evidence on the division and correlation of the fish-bearing Devonian strata in South China and deepens the understanding of the biogeography of the Devonian bothriolepids.

Distinct Assembly Mechanisms for Prokaryotic and Microeukaryotic Communities in the Water of Qinghai Lake
Mingxian Han, Jianrong Huang, Jian Yang, Beichen Wang, Sun Xiaoxi, Hongchen Jiang
2023, 34(4): 1189-1200.   doi: 10.1007/s12583-023-1812-8
[Abstract](102) [FullText HTML](102) [PDF 849KB](26)

Assembly processes of prokaryotic and microeukaryotic community is an important issue in microbial ecology. However, unclear remains about the relative contribution of deterministic and stochastic processes to the shaping of prokaryotic and microeukaryotic communities in saline lake water. Here, we systematically investigated the assembly processes governing the prokaryotic and microeukaryotic communities in Qinghai Lake with the use of Illumina sequencing and a null model. The results showed that both deterministic and stochastic processes play vital roles in shaping the assemblies of prokaryotic and microeukaryotic communities, in which stochastic processes appeared to dominate (> 70%). Prokaryotic communities were mainly governed by non-dominant processes (60.4%), followed by homogeneous selection (15.8%), variable selection (13.6%) and dispersal limitation (10.2%), whereas microeukaryotes were strongly driven by non-dominant processes (68.9%), followed by variable selection (23.6%) and homogenizing dispersal (6.3%). In terms of variable selection, nutrients (e.g., ammonium, dissolved inorganic carbon, dissolved organic carbon and total nitrogen) were the major factors influencing prokaryotic and microeukaryotic community structures. In summary, prokaryotes and microeukaryotes can be predominantly structured by different assembly mechanisms, in which stochasticity is stronger than deterministic processes. This finding helps to better comprehend the assembly of prokaryotic and eukaryotic communities in saline lakes.

Spatiotemporal Variability in Extreme Temperature Events in an Arid-Semiarid Region of China and Their Teleconnections with Large-Scale Atmospheric Circulation
Lin Zhang, Yanfeng Liu, Menggui Jin, Xing Liang
2023, 34(4): 1201-1217.   doi: 10.1007/s12583-021-1517-9
[Abstract](35) [FullText HTML](35) [PDF 19258KB](4)

With a warming climate, temperature extremes have been a main global issue in recent decades due to their potential influence on the sustainable development of human life and natural ecosystems. In this study, 12 indicators of extreme temperature events are used to evaluate the spatiotemporal distribution, periodic structure and teleconnections with large-scale atmospheric circulation in Xinjiang, Northwest China by combining wavelet coherence (WTC) analysis based on continuous wavelet transform (CWT) analysis with the sequential Mann-Kendall test. We find that over the past six decades, the climate in Xinjiang has become warmer and has suffered from increases in the frequency of warm extremes and decreases in the frequency of cold extremes. Warm extremes have mainly occurred in the southern Tianshan Mountains surrounding the Tarim Basin and western part of the Taklamakan Desert, and cold extremes have primarily occurred in the southwestern Altai Mountains and northern foot of the Tianshan Mountains. Extreme temperature events, including warm extremes, cold extremes, and other temperature indices, have significant interannual variability, with the main oscillation periods at smaller (2–4-year band), intermediate (4–7-year band), and greater time scales in recent decades. Furthermore, cold-extreme indices, including frost days, cool days, and cool nights all show a clear changepoint during 1990–1997 at the 95% confidence level, and both ice days and cold spell duration indicator have a potential changepoint during 1981–1986. However, the changing points for warm-extreme indices are detected during 1992–1998. The temperature variables are significantly correlated with the EI Niño-Southern Oscillation (ENSO) and Arctic Oscillation (AO), but less well correlated with the Pacific Decadal Oscillation (PDO). The phase difference in the WTC spectra is not uniform between temperature extremes and climatic oscillations. Our findings will have important implications for local governments in taking effective measures to mitigate the potential effects of regional climate warming due to human activities in Xinjiang.

Reconstructing Centennial-Scale Water Level of Large Pan-Arctic Lakes Using Machine Learning Methods
Xinge Liang, Chunqiao Song, Kai Liu, Tan Chen, Chenyu Fan
2023, 34(4): 1218-1230.   doi: 10.1007/s12583-022-1739-5
[Abstract](32) [FullText HTML](32) [PDF 6361KB](2)

The pan-Arctic region has the largest number of lakes in the world, which is rather sensitive to changing climate. It is urgently needed to understand how these lakes were changing in the long term. However, there are few lakes with long-term historical monitoring of water level, understanding the hydrologic changes of pan-Arctic lakes over the past century requires the data reconstruction by state-of-art techniques. This study used machine learning algorithms to reconstruct the water level of pan-Arctic lakes on a centennial scale. It further investigated their relationship with long-term hydrological and climatic variables. Comparison of the reconstructed results by four different machine learning models shows that the extreme gradient boosting tree (XGBoost) is better than other three models. Overall, the centennial-scale reconstruction using the XGBoost model performs best for most study lakes. Based on the reconstructed results, we can observe that water level changes of several North American lakes are correlated with potential evapotranspiration, followed by precipitation, while the Eurasian lakes are more strongly associated with temperature and wet day frequency. The water level dynamics of pan-Arctic lakes could be largely attributed to Arctic Oscillation and Atlantic Multidecadal Oscillation. This study is expected to advance our understanding of the pan-Arctic lake water level changes in the past century and to provide a feasible method for reconstructing the regional lake water level in the long term.

Geological Genesis of Alkaline Magnesium-Type Groundwater within the Ophiolitic Rocks Areas in Southwestern Turkey
Selma Demer
2023, 34(4): 1231-1248.   doi: 10.1007/s12583-022-1767-1
[Abstract](44) [FullText HTML](44) [PDF 7299KB](9)

The groundwaters within the ophiolite nappes in the southwestern part of Turkey have different physical and geochemical characteristics and are divided into five different groundwater facies. These are (1) Mg-HCO3, (2) Mg-HCO3-CO3, (3) Mg-CO3-HCO3, (4) Na-Ca-Cl-CO3, and (5) Ca-Mg-HCO3. The waters interact with ophiolites, mainly made up of basic-ultrabasic rocks, are characterized by alkaline and hyperalkaline character. Alkaline waters have high Mg, HCO3 contents and Μg/Ca ratio, and hyperalkaline water has high Na, Ca contents, and low Μg/Ca ratio. The waters in the study area formed by the interaction of meteoric waters with variously serpentinized ultramafic rocks under low-temperature conditions. Silicate weathering is the main hydrogeochemical process that plays a role in the chemical composition of water. Mg-HCO3-type groundwaters are produced under open-system conditions with respect to CO2 due to meteoric water-serpentinized peridotite interactions in a shallow environment. Deep-seated groundwaters are Na-Ca-Cl-CO3-type waters with high pH (TN-8 sample with pH 10.72), depleted in terms of Mg due to water-peridotite interaction under closed-system conditions with respect to CO2. Salda Lake with an alkaline character and high Mg and Na content is characterized by high evaporation and hydromagnesite deposition.

Analysis of the Sedimentary Characteristics of a Modern Distributive Fluvial System: A Case Study of the Great Halten River in the Sugan Lake Basin, Qinghai, China
Xianghui Zhang, Changmin Zhang, Adrian Hartley, Qinghai Xu, Wenjie Feng, Taiju Yin, Rui Zhu
2023, 34(4): 1249-1262.   doi: 10.1007/s12583-022-1715-0
[Abstract](28) [FullText HTML](28) [PDF 37350KB](5)

Understanding controls on river planform changes can help to build predictive models for distributive fluvial systems, and then guide the oil and gas exploration. To do this we have undertaken a detailed investigation of the modern Great Halten River distributive fluvial system from the Sugan Lake Basin, Qinghai, China. Unmanned aerial vehicle (UAV) photography, satellite remote sensing data and elemental analysis were used to determine differences in the sedimentary characteristics of the distributive fluvial system. From the apex to the toe, the changes in the slope, river morphology, sedimentary characteristics and element content in different regions were determined and three facies belts: "proximal", "medial" and "distal" were identified. We found that the sedimentary structure and elemental content characteristics of each facies differ greatly. We compare the large-scale evolution of rivers from braided to meandering rivers, and the fine description of sedimentary characteristics in combination with each observation, we strengthen our overall understanding of the modern DFS from macro to micro scale. At the same time, we summarize the sedimentation model of the Great Halten River DFS, and our study provides a reference for establishing the sedimentary model in continental petroliferous basins.

Downstream Channel Evolution and Its Causes in the Yuan River during the Qing Dynasty
Dandan Zheng, Yuhui Gui, Jian Kuang, He Bing
2023, 34(4): 1263-1271.   doi: 10.1007/s12583-021-1600-2
[Abstract](342) [FullText HTML](260) [PDF 17685KB](34)

The determination of channel evolutions and the causes is important for reconstructing the evolutionary history of river landforms. This study aimed to elucidate the downstream channel evolution of the Yuan River in Hunan Province, China, during the Qing Dynasty via Landsat 8 satellite image data and relevant literature. The objective was to establish the modes of channel evolution and discuss the significance of historical climate change. The downstream paleochannel of the Yuan River was identified in the Late Ming Dynasty and Early Qing Dynasty (1600–1644 AD), the Kangxi-Qianlong periods of the Qing Dynasty (1661–1796 AD), the Late Qing Dynasty (1840–1912 AD), and the World War Ⅱ (1939–1945 AD), and three main modes of river evolution were determined. Using remote sensing data and the ancient literature, the evolution characteristics of the paleochannel in the Lower Yuan River were analyzed and its distribution across historical periods was comprehensively revealed. The findings reveal a strong correlation between channel evolution, flood events, and climate change. Numerous flood events that occurred from the Late Qing Dynasty to the World War Ⅱ caused a high rate of channel evolution, demonstrating the combined effects of climate change and human activities. These findings will help adopt robust and resilient hydrological management methods in the future of a changing climate.

Compression Characteristic and Creep Behavior of Moraine Soil at Xingkang Bridge, West Sichuan, China
Xifeng Guo, Xinfu Xing, Zhonghao Wang, Qiang Cheng, Lei Huang, Ning Li, Shengming Hu
2023, 34(4): 1272-1279.   doi: 10.1007/s12583-022-1800-4
[Abstract](66) [FullText HTML](66) [PDF 5069KB](12)

The compression and creep characteristics of moraine soil are important mechanical properties of geomaterials to be analyzed during the construction process of engineering projects. However, related references about these characteristics through large-size in-situ tests have rarely been reported. In this study, in-situ tests of particle size distribution, compression deformation, and compression creep were conducted at the Xingkang Bridge, West Sichuan, China. The results show that the uniformity coefficient of moraine soil ranges from 12.1 to 183.3, and gradation coefficient ranges from 0.4 to 2.8. The total compression deformations of moraine samples during the conventional compression deformation test are 4.70, 4.07, and 0.47 mm, and their residual deformations are 2.81, 2.45, and 0.22 mm, respectively. The deformation modulus ranges from 127.3 to 676.4 MPa, and elastic modulus ranges from 316.3 to 765.7 MPa. During compression creep tests, moraine soil enters the steady creep stage after 3.8 h of loading pressure at 445 kPa, and it keeps steady after 14 h of loading pressure at 900 kPa. The Burgers model and generalized Kelvin model predict the deformation well in transient, deceleration and steady creep stages. Results provide a valuable reference for the analysis of the compression deformation and creep behavior of moraine soil during engineering construction and management.

Study on Shear Strength Characteristics of Columnar Jointed Basalt Based on in-situ Direct Shear Test at Baihetan Hydropower Station
Peng Xia, Xinli Hu, Shuangshuang Wu, Chunye Ying, Chu Xu, Xuan Wang, Hao Chen
2023, 34(4): 1280-1294.   doi: 10.1007/s12583-022-1669-2
[Abstract](80) [FullText HTML](74) [PDF 22523KB](8)

Columnar jointed basalt (CJB) widely distributes in the dam site of the Baihetan Hydropower Station. The columnar joint structure and fracture development of CJB have significant influence on the mechanical properties of rock mass, and the mechanical properties of CJB are of great significance to the Baihetan Hydropower Project. Therefore, in-situ direct shear tests were carried out on ten test adit at different locations in the dam site area to study the shear behavior of CJB. In this study, 21 sets of in-situ direct shear tests were conducted for rock types of type Ⅱ2, type Ⅲ1 and type Ⅲ2, with horizontal and vertical shear planes and two different specimen sizes of CJB. Shear strength parameters of CJB were obtained by linear fitting of in-situ direct shear test results based on the Mohr-Coulomb strength criterion. The results indicate that the shear strength parameters of CJB with horizontal shear plane increase as the increase of rock type grade. The shear strength parameters of CJB show obvious anisotropy and the friction coefficient of the horizontal shear plane is greater than the vertical shear plane. The friction coefficient in the horizontal direction of the shear plane is 1.27 times that in the vertical direction of the shear plane. With the increase of rock type grade, the difference of friction coefficient becomes larger. However, the cohesion changes little whether the shear plane is horizontal or vertical. In addition, the size effect of CJB in this area is significant. The shear strength parameters of large size (100 cm × 100 cm) specimens are lower than those of regular size (50 cm × 50 cm) specimens. The reduction of cohesion is greater than that of the friction coefficient. For rock type Ⅲ2, the cohesion of large-size specimens is 0.637 of the regular-size specimens. The reduction percentage of the friction coefficient for type Ⅲ2 is 1.66 times that of type Ⅲ1. The reduction percentage of the cohesion for type Ⅲ2 is 1.27 times that of type Ⅲ1. The size effect decreases with the increase of rock type grade. The research results of this study can provide an important basis for the selection of rock mechanics parameters in the dam site area of Baihetan Hydropower Station and the stability analysis of the dam foundation and rocky slopes.

Super-Enrichment Mechanisms of Strategic Critical Metal Deposits: Current Understanding and Future Perspectives
Shao-Yong Jiang, Wei Wang, Hui-Min Su
2023, 34(4): 1295-1298.   doi: 10.1007/s12583-023-2001-5
[Abstract](42) [FullText HTML](42) [PDF 712KB](9)
How did Jawed Vertebrates Originate and Rise?
Min Zhu, Youan Zhu, Zhikun Gai, Wenjin Zhao, Tuo Qiao, Jing Lu
2023, 34(4): 1299-1301.   doi: 10.1007/s12583-023-1907-2
[Abstract](31) [FullText HTML](31) [PDF 1006KB](4)
When and How Plate Tectonics Began?
Shao-Bing Zhang
2023, 34(4): 1302-1303.   doi: 10.1007/s12583-023-1870-y
[Abstract](40) [FullText HTML](40) [PDF 320KB](10)
How to Effectively Prevent and Mitigate Geomagnetic Hazard?
Xiangyun Hu, Bo Han, Tao Yu
2023, 34(4): 1304-1305.   doi: 10.1007/s12583-023-1883-6
[Abstract](20) [FullText HTML](20) [PDF 285KB](2)
How did Reefs Evolve during the Precambrian-Cambrian Transition?
Yangfan Li, Fei Li
2023, 34(4): 1306-1307.   doi: 10.1007/s12583-023-1871-x
[Abstract](25) [FullText HTML](25) [PDF 5638KB](5)
Critical Metals Ga, Ge and In in the Global Pb-Zn Deposits: Current Understanding, Challenges and Perspectives
Yi Zheng, Peng-Peng Yu, Zhan-Ke Li, Suo-Fei Xiong, Ling-Li Zhou, Jia-Xi Zhou, Chang-Ming Wang, Yu-Miao Meng, Yu Zhang, Ye-Jian Wang, Jing Xu, Yue Wu, Lan-Xuan Guo, Taiping Zhao
2023, 34(4): 1308-1311.   doi: 10.1007/s12583-023-1909-0
[Abstract](47) [FullText HTML](47) [PDF 477KB](11)
How does the New Generation of Information Technology Support the Urban Transparent Geology?
Yuyong Jiao, Wanting Ye, Luyi Shen, Fei Zheng
2023, 34(4): 1312-1312.   doi: 10.1007/s12583-023-1885-4
[Abstract](29) [FullText HTML](29) [PDF 299KB](0)
What are the Limiting Environmental Factors for the Evolution of Early Eukaryotic Diversity?
Shuichang Zhang, Xiaomei Wang, Huajian Wang, Qing Tang, Fenglian Zhang, Dan Lü
2023, 34(4): 1313-1314.   doi: 10.1007/s12583-023-1876-5
[Abstract](35) [FullText HTML](35) [PDF 316KB](3)
30 Years of Climate Change before and after the Impoundment of the Three Gorges Reservoir
Junqi Liu, Chen Lin, Shan Dong, Ruixue Feng, Aijun Su, Jinghui Cui, Shupeng Yu
2023, 34(4): 1315-1318.   doi: 10.1007/s12583-022-1725-y
[Abstract](24) [FullText HTML](24) [PDF 1004KB](5)
Fish Swimming Traces from the Upper Devonian of Wuhan, South China
Ruo-Ying Fan, Rui-Wen Zong, Yi-Ming Gong
2023, 34(4): 1319-1322.   doi: 10.1007/s12583-021-1509-9
[Abstract](34) [FullText HTML](34) [PDF 10873KB](6)

Vol 34, No 4 , 2023

ISSN 1674-487X

CN 42-1788/P

Editor in Chief: Yanxin Wang

Managing Editors: Zhong-Qiang Chen, Shao-Yong Jiang

Associate Editor:

Shu Jiang,Changdong Li,Rui Ma 
Qiliang Sun,Timothy M. Kusky,Dun Wang 
Lunche Wang,Long Xiao,Xin-Fu Zhao
Keqing ZongRenguang Zuo

2022 Impact Factor 3.3