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2018 Vol. 29, No. 4

2018, 29(4): .
Special Volume on Permian and Triassic Worlds: A Thematic Issue Delicated to Professor Zunyi Yang's 110th Anniversary
Great Paleozoic-Mesozoic Biotic Turnings and Paleontological Education in China:A Tribute to the Achievements of Professor Zunyi Yang
Zhong-Qiang Chen, Laishi Zhao, Xiangdong Wang, Luo Mao, Zhen Guo
2018, 29(4): 721-732. doi: 10.1007/s12583-018-0797-1
Professor Zunyi Yang is a pioneer paleontologist who established the earliest Paleontological education and research in China, and has contributed his lifetime to promotion of Chinese paleontological education and researches as well as the studies on the Permian-Triassic (P-Tr) mass extinction and its possible causes. Yang has studied six fossil clades and trace fossils, together with his colleagues, he has established 6 new species of cephalopods, 1 new genus and 15 new species of gastropods, 8 new genera and 31 new species of bivalves, 17 new genera and 66 new species of brachiopods, 1 new genus and 4 new species of ophiuroids, 2 new genera and 7 new species of triopsids (Crustacea), and 3 new ichnogenera and 7 new ichnospecies of trace fossils. Yang led the 2nd IGCP working on the P-Tr mass extinction in the world. His group's excellent works on basic stratigraphy and paleontology enable the GSSP of P-Tr boundary (PTB) to be ratified in China. Yang's earlier works on three-episode extinction pattern and volcanism-causing extinction hypothesis are also highlighted here to show how their first-hand data and initiative hypothesis have influenced the current and ongoing debates on the P-Tr crisis and possible causation. Yang school's extinction pattern is reviewed here, and their 2nd phase of extinction is marked by a dramatic loss in biodiversity, pointing to a widely accepted mass extinction. The 3rd extinction is characterized by ecological collapse of ecosystem structures and disappearance of the PTB microbialite ecosystem, while the 1st extinction (also prelude extinction) is indicated by the collapses of deep-water and reef ecosystems. Updated studies show that the volcanic ashes near the PTB originated from silicic, subduction-related igneous activity with little or no basaltic input. This subduction zone activity is related to closure of the Paleo-Tethys Ocean, and the intensity and frequency of the volcanic activity appear to increase near the P-Tr extinction interval. Hg anomalies (Hg/TOC ratios and Hg isotopes) were also detected from the P-Tr extinction interval, and they are interpreted as the results of enhanced volcanic-generated atmospheric mercury, which was injected by the violate eruption of the Siberian traps. Thus, the peak felsic volcanism is coeval with violate eruption of Siberian traps, and the coupled relationship between both types of volcanisms and biotic extinction suggests a causal relationship.
Final Results and Recommendations of the Last 10 Years IGCP 572 and 630 Field Workshops in South Turkey, Oman, India (Kashmir) and Armenia
Aymon Baud
2018, 29(4): 733-744. doi: 10.1007/s12583-018-0796-2
Being involved in the organization of IGCP 572 field workshops in Turkey (2009), in Oman (2010), as in the following IGCP 630 field workshops in Kashmir (India, 2014) and in Armenia (2017), I co-wrote for each of them detailed guidebooks and extended reports that can be found and downloaded from ResearchGate website. This paper summarizes the final results obtained by IGCP 572 and 630 members from these four important field workshop sites in the past 10 years, and also attempts to make recommendations for future studies based on these unique localities surrounding the Tethys Ocean. The first field workshop of IGCP 572 was organized in South Turkey in September, 2009, with the logistical support of Dr. Erdal Kosun from the Antalya University. Following the South Turkey field workshop, eight important papers have been published and concerned the well-preserved Permian-Triassic boundary (PTB) microbialites and their ecosystems (including ostracodes, brachio-pods, and many of other clades). The 3rd IGCP 572 annual field workshop was held during February, 2010 in the Sultanate of Oman, with Dr. Michaela Bernecker and the deep support from the GuTech University in Muscat. More than 15 papers have derived from the P-Tr successions that IGCP 572 members have investigated during this workshop, including the first study on oceanic acidification based on Boron isotopes. New paleontological studies are still on progress, and concern the Smithian ammonoids, Lower Triassic shark teeth and dental remains as well as basal Triassic conodonts, cri-noids and ammonoids. The 1st IGCP 630 annual field workshop was held during November, 2014 in Srinagar, Kashmir, and North India, with the helpful assistance of Prof. Ghulam Bhat from Jammu University. This meeting renewed studies on the classic Guryul Ravine and adjacent P-Tr boundary sections in that region, with new geochemical works on carbon isotopes and pyrite framboids as well as a detailed Induan conodont taxonomy and zonation. Other new paleontological works concern the palynology of the Guryul Ravine Section as some well-preserved organic eukariotic protist (thecamoe-bians) that cross without damage the PTB. Lilit Sahakyan, Aymon Baud, and Zhong-Qiang Chen or-ganized the 5th IGCP 630 annual conference and field workshop in Armenia on October 8-14, 2017. Several PTB and Lower Triassic sections have been systematically sampled for biogeochemical and geobiological studies. These Armenian sections provide unique paleoenvironmental settings that have the longest record, from Griesbachian to Dienerian, of microbial proliferation following the P-Tr mass extinction in the world. The basal Triassic giant sponge-microbial build-ups are encouraging more comprehensive studies on metazoan-microbial reef developments after the greatest extinction event.
Sequence Stratigraphic Model of Middle Permian Barakar Formation from a Marginal Gondwana Basin, India
Joyjit Dey, Souvik Sen
2018, 29(4): 745-754. doi: 10.1007/s12583-018-0791-7
Gondwana deposits are extensively found across the continents. Here we study the Middle Permian Barakar Formation from the marginal Gondwana Basin, eastern India, being deposited in a normal fault setting. Availability of extensive cores as well as geophysical log suites (gamma-resistivity-density from drilled wells) from the study area helped us achieving high resolution interpretation. Core study identifies fluvial sedimentary architectures, which were correlated with the geophysical logs and modeled field-wide to understand vertical and horizontal facies disposition. The facies analysis has been used to establish a sequence stratigraphic model of the cyclic Barakar deposition. Four major fining upward depositional sequences were identified, each sequence comprises of low accommodation system tract (LAST) at base and high accommodation system tract (HAST) at top. LAST is characterized by vertically stacked, multistory amalgamated channel sandstone dominated facies, while floodplain dominated facies characterizes HAST, reflecting a gradual shift from braided to meandering depositional system from bottom to top of each cycle. Study reveals depocenter to be in the western part, supported by eastward thinning of sediment packets, all being deposited in a half-graben setting.
Correlation of Lopingian to Middle Triassic Palynozones
Hendrik Nowak, Elke Schneebeli-Hermann, Evelyn Kustatscher
2018, 29(4): 755-777. doi: 10.1007/s12583-018-0790-8
Terrestrial floras underwent important changes during the Lopingian (Late Permian), Early Triassic, and Middle Triassic, i.e., before, during, and after the end-Permian mass extinction. An accurate account of these developments requires reliable correlation. Macrofossils of land plants can only provide a low-resolution biostratigraphy, while detailed zonation schemes based on palynomorphs are available for many regions. Their applicability is still limited due to several factors, such as (micro-)floral provincialism, a lack of suitable marker taxa commonly occurring at important boundaries, and in many cases a lack of independent age control. Nevertheless, these paly-nostratigraphic schemes are regularly used for dating and correlation of successions between differ-ent regions. To support such efforts, the biozonation schemes based on palynomorphs from the Lop-ingian up to and including the Middle Triassic from across the world are summarized and revised. Thus, a consistent correlation of palynozones with the currently recognized international stages is established.
Permian-Triassic Charophytes:Distribution, Biostratigraphy and Biotic Events
Spencer G Lucas
2018, 29(4): 778-793. doi: 10.1007/s12583-018-0786-4
Permian charophytes are known from the Ukraine, Russia, Kazakhstan, Germany, Saudi Arabia, China, the USA, Brazil, Paraguay and India. Most of these records are of Middle-Late Permian Age and are the basis of local biostratigraphic zonation in southern Russia and China. Development of a robust Permian charophyte biostratigraphy will require a more extensive record. Triassic charophytes are known from Germany, Sweden, Poland, Slovenia, Bulgaria, the Ukraine, Russia, Morocco, Congo, the USA, Argentina, Kazakhstan and China. This encompasses records from all Triassic stages and has been the basis of detailed biostratigraphic zonation in southern Russia-Kazakhstan-eastern Europe. Permian and Triassic charophyte biostratigraphy at the level of genus does not provide detailed correlations beyond local or regional schemes. Nevertheless, it does identify some important evolutionary datums that constrain the timing of important biotic events in the Permian-Triassic evolutionary history of the Charophyta, including:(1) Early Permian extinction of the Palaeocharaceae; (2) Late Permian extinction of the "Trochiliscales" (Moellerinales); (3) Carboniferous origin of the paraphyletic Porocharaceae, soon followed during the Permian by the origin of the multicellular basal plate; and (4) an important generic turnover of charophytes across the Triassic-Jurassic boundary, though there are insufficient data to identify this as a mass extinc-tion.
A Griesbachian (Early Triassic) Mollusc Fauna from the Sidazhai Section, Southwest China, with Paleoecological Insights on the Proliferation of Genus Claraia (Bivalvia)
Yunfei Huang, Jinnan Tong, Margaret L Fraiser
2018, 29(4): 794-805. doi: 10.1007/s12583-017-0966-7
After the end-Permian mass extinction, genus Claraia (Bivalvia) was the most abundant and most noticeable fossil during the survival and recovery stage. However, the reasons for the proliferation of Claraia are still debated. This paper describes a new Griesbachian (Early Triassic) mollusc fauna from deep-water settings in South China in the aftermath of end-Permian mass extinction. This fauna yielded five bivalve species in two genera (Claraia griesbachi, C. wangi, C. stachei, C. radialis, and Promyalina putiatinensis) and two ammonoid species (Ophiceras sp. and Ussuridiscus sp.) and could be assigned to the Claraia wangi-C. griesbachi assemblage zone, indicating a Middle-Late Griesbachian Age. The bivalves were dominated by Claraia griesbachi and were featured by articulated Claraia fossils. As Claraia was epibyssate, it was an excellent autochthonous fauna. While the shallow and deep marine water became dysoxic to anoxic globally, as indicated by recent studies of the early Early Triassic, we suggest the genus Claraia could tolerate dysoxic and/or anoxic conditions and its proliferation could be attributed to its physiological features which were adapted to the stressed environment. The wide dis-tribution of Claraia was probably related to its planktonic larval stage. Where the larva of Claraia could have been transported by ocean flow and increased its potential for long-distance dispersal. In addition, Claraia was a significant disaster and opportunistic taxon during the Early Triassic based on observations in South China.
Western Tethyan Epeiric Ramp Setting in the Early Triassic:An Example from the Central Dinarides (Croatia)
Dunja Aljinović, Micha Horacek, Leopold Krystyn, Sylvain Richoz, Tea Kolar-Jurkovšek, Duje Smirčić, Bogdan Jurkovšek
2018, 29(4): 806-823. doi: 10.1007/s12583-018-0787-3
In the central part of the External Dinarides in Plavno, Croatia, near Knin, a remarkably thick (927.5 m) Early Triassic depositional sequence was investigated. The Plavno sequence starts in the EarlyGriesbachian and ends with a continuous transition into the Anisian strata. A complete 13C isotope curve has been achieved and combined with conodonts, bivalves and ammonoids to establish and correlate stage and substage boundaries. The δ13C curve is consistent with former studies. It displays a general increase from the Griesbachian to a prominent maximum beyond the +8‰ amplitude around the Dienerian-Smithian boundary (DSB), followed by a steep and continuous decline to low, negative values in the Smithian. Around the Smithian-Spathian boundary (SSB) a steep rise to a second maximum occurred. It is followed by a saw-tooth shaped decline in the Spathian and a similar increase to a peak at the Spathian-Anisian boundary (SAB).Sedimentologically, the Plavno sequence is interpreted as having been deposited on an extensive epeiric ramp under long-term transgressive conditions, sharing depositional characteristics of both the epeiric platform and the carbonate ramp. The entire Plavno sequence was deposited above the storm-wave base and was storm influenced. Three informal members are differentiated:1) the dolo-stone member (Early Griesbachian); 2) the siliciclastic member (red-coloured shale, siltstone, sand-stone with oolitic/bioclastic grainstone intercalations), which can be further divided into lower, mid-dle and upper intervals (Late Griesbachian, Dienerian and Smithian); and 3) the mudstone member (grey lime mudstones, marls and calcisiltites with common ammonoids and gastropods-Spathian). The Plavno sequence is compared with other western Tethyan sections. Observed differences stem from local controls on deposition in the overall shallow marine environment.
A Taxonomic Re-Assessment of the Novispathodus waageni Group and Its Role in Defining the Base of the Olenekian (Lower Triassic)
Zhengyi Lyu, Michael J Orchard, Zhong-Qiang Chen, Laishi Zhao, Lei Zhang, Xiumei Zhang
2018, 29(4): 824-836. doi: 10.1007/s12583-018-0795-3
Lower Triassic conodont biostratigraphy has been well studied around the world in the past decades, but the Induan-Olenekian boundary (IOB) remains undecided. The Novispathodus waageni group has been taxonomically re-assessed based on abundant new materials from the Jianshi and Chaohu sections, South China. New study shows that Nv. waageni typically possesses:(1) an approximately equi-dimentional P1 blade element, (2) an accurate upper profile with denticle height descending in both directions, (3) a denticulated posterior edge (lower denticles posterior of the highest denticle), and (4) a round basal cavity outline. Of the three proposed subspecies of the waageni species, both Nv. waageni waageni (Sweet, 1970) and Nv. w. eowaageni (Zhao and Orchard, 2005) are valid, and the former differs clearly from Nv. w. eowaageni in having (1) a slightly higher length/height ratio (holotype=1.30:1.23), (2) a thicker blade, sometimes with medial thickening, (3) fewer (broader) denticles per unit length, (4) generally recurved denticles, not straight and upright, (5) highest denticles closer to posterior, (6) common differentiation of a posterior cusp, and (7) more sinuous basal profile, with increased posterior upturning. A third subspecies illustrated as Nv. waageni n. subsp. A sensu Goudemand, 2014 is not conspecific with older individuals of Nv. w. eowaageni, and also cannot be assigned to the Nv. waageni group. Abundant new materials demonstrate a clear ontogenic process for Nv. w. eowaageni, indicating that Nv. w. eowaageni occurring in the Induan-Olenekian boundary (IOB) succession is rather stable. Small, earlier individuals (i.e., those from Bed 225 in Jianshi) are referred to as Nv. w. eowaageni Morphotype A, and are thought to have likely evolved from Ns. dieneri Morphotype 3, and to be the precursor of mature elements of Nv. w. eowaageni. The first appearance datum of Nv. w. eowaageni therefore is an ideal mark defining the IOB.
Nitrogen and Carbon Isotope Data of Olenekian to Anisian Deposits from Kamenushka/South Primorye, Far-Eastern Russia and Their Palaeoenvironmental Significance
Yuri D Zakharov, Micha Horacek, Alexander M Popov, Liana G Bondarenko
2018, 29(4): 837-853. doi: 10.1007/s12583-018-0792-6
The Kamenushka Formation, exposed in the northern part of South Primorye (Kamenushka-1 and Kamenushka-2 sections), is one of the few localities in the world with richly fossiliferous Lower-Upper Olenekian sedimentary successions. Lower to Middle Triassic ammonoid-, brachiopod-and conodont-bearing silty-clayey deposits of the Kamenushka-1 and Kamenushka-2 sections have been isotope-geochemically investigated in detail. As a result, these sections, together with the previously investigated Abrek Section, exposed in the southern part of South Primorye, provide almost complete 15Norg- and 13Corg- records for the Lower Triassic of this region. Nine N-isotope intervals and the five negative C-isotope excursions, reflecting, apparently, unstable climatic and hydrological conditions, have been distinguished in the Lower Triassic of South Primorye. On the basis of the new C-isotope data the Mesohedenstroemia bosphorensis Zone (upper part), Shimanskyites shimanskyi and Neocolumbites insignis zones of South Primorye are correlated now with the Lower Smithian part of the Yinkeng Formation, the Upper Smithian part of the Helongshan Formation and the Middle Spathian part of the Nanlinghu Formation in South China, respectively, as has been observed in the Abrek, Kamenushka-2, West Pingdingshan and Majiashan sections.
Palaeoecological Analysis of Trace Fossil Sinusichnus sinuosus from the Middle Triassic Guanling Formationin Southwestern China
Mao Luo, Yi-Ming Gong, G.R. Shi, Zhong-Qiang Chen, Jinyuan Huang, Shixue Hu, Xueqian Feng, Qiyue Zhang, Changyong Zhou, Wen Wen
2018, 29(4): 854-863. doi: 10.1007/s12583-018-0794-4
The Luoping Biota discovered from the early Middle Triassic (Anisian) Guanling Formation of southwestern China represents a fully recovered shallow marine ecosystem, marking the end point of Early Triassic biotic recovery following the end-Permian mass extinction. Contemporaneously preserved are prolific trace fossils, which offer good opportunities to understand the palaeoecology of marine invertebrates from a fully recovered shallow marine ecosystem. Here we present a newly discovered sinuous branching burrow from the fossil-bearing unit in Member Ⅱ of the Guanling Formation. Several features, including the horizontal regular sinuous nature, the branching pattern, typical H-junction, and the small wavelength/amplitude ratio of these sinuous structures within the burrow systems justify assignment of these traces as Sinusichnus sinuosus, a trace possibly produced by decapod crustaceans. Close association of S. sinuosus with Rhizocorallium commune suggests a deposit-feeding strategy of these trace makers. The newly reported Anisian material from the Guan-ling Formation in Luoping represents first report of Sinusichnus from South China. The global record of Sinusichnus occurrence suggests that these burrows might have an older history than Early Middle Triassic.
Stratigraphic Definition and Correlation of Middle Triassic Volcaniclastic Facies in the External Dinarides:Croatia and Bosnia and Herzegovina
Duje Smirčić, Tea Kolar-Jurkovšek, Dunja Aljinović, Uroš Barudžija, Bogdan Jurkovšek, Hazim Hrvatović
2018, 29(4): 864-878. doi: 10.1007/s12583-018-0789-1
Middle Triassic volcaniclastic depositsin the External Dinarides of Croatia and Bosnia and Herzegovina are related to the rifting of the Tethyan Ocean. Three localities in the External Dinarides:Donje Pazarište, Bosansko Grahovo and Zelovo were biostratigraphically analysed in this study. The Middle Triassic carbonate deposits with volcaniclastic interlayers in Donje Pazarište were defined by means of conodonts. Rare ammonoid specimens were collected.Recovered conodont and ammonoid taxa suggest these sections are of Early Illyrian to Early Fassanian Age. The section studied in Bosansko Grahovo is dominantly composed of volcanic and volcaniclastic rocks. Limestone peperites were collected for conodont analysis. Two conodont zones were defined, suggesting volcanic activity in the same, from Lower Illyrian to Fassanian, time interval. The Zelovo Section was biostratigraphically investigated by several authors. The pietra verde deposits from Zelovo are referred as late Fassanian to Early Longobardian Age. Biostratigraphic correlation from mentioned three localities imply that the magmatic activity in the External Dinarides, and formation of different volcaniclastic facies lasted from Illyrian to Longobardian, similar as in the surrounding western Tethyan territories.
Paleoecological Response of Corals to the End-Triassic Mass Extinction:An Integrational Analysis
George D Stanley Jr, Hannah M E Shepherd, Autumn J Robinson
2018, 29(4): 879-885. doi: 10.1007/s12583-018-0793-5
The end-Triassic (also Triassic-Jurassic) mass extinction severely affected life on planet Earth 200 million years ago. Paleoclimate change triggered by the volcanic eruptions of the Central Atlantic Magmatic Province (CAMP) caused a great loss of marine biodiversity, among which 96% coral genera were get lost. However, there is precious little detail on the paleoecology and growth forms lost between the latest Triassic extinction and the Early Jurassic recovery. Here a new pilot study was conducted by analyzing corallite integration levels among corals from the latest Triassic and Early Jurassic times. Integration levels in corals from the Late Triassic and Early Jurassic were determined through both the Paleobiology Database as well as from a comprehensive museum collection of fossil corals. Results suggest that in addition to a major loss of diversity following the end-Triassic mass extinction, there also was a significant loss of highly integrated corals as clearly evidenced by the coral data from the Early Jurassic. This confirms our hypothesis of paleoecological selectivity for corals following the end-Triassic mass extinction. This study highlights the importance of assigning simple to advanced paleoecological characters with integration levels, which opens a useful approach to understanding of mass extinction and the dynamics of the recovery.
Upper Darriwilian (Middle Ordovician) Radiolarians and Ostracods from the Hulo Formation, Zhejiang Provicnce, South China
Yuhao Yi, Aihua Yuan, Jonathan C Aitchison, Qinglai Feng
2018, 29(4): 886-899. doi: 10.1007/s12583-017-0951-6
Considerable research has been done on the Ordovician marine fossils from South China, including macrofossils such as brachiopods, graptolites, bivalves, trilobites, some microfossils like conodonts and acritarches. However, radiolarians and ostracods that are also important constituents of the Ordovician marine ecosystem have been paid little attention in this region. In this study, ten radiolarians species belonging to four genera and sixteen ostracods species grouped into nine genera were found from the Hulo Formation at the Hengdu Section of the Jiangshan District, western Zhejiang Province, South China. The fossil-bearing strata belong to the graptolite Pterograptus elegans Zone which indicates the Late Darriwilian Age. This radiolarian fauna is the first record of the Middle Ordovician radiolarian body fossils and also the earliest Ordovician radiolarian fauna reported from South China. The occurrence of Beothuka in this fauna extends the stratigraphic range of the genus to the Upper Darriwilian. Reviews of previous literatures suggest that the diversity of Beothuka was greater during the Early Ordovician, and then declined gradually from the Early Ordovician to the Middle Ordovician before its extinction. The co-occurring ostracod fauna belongs to a shallow-water ecotype. This is contrary to the host lithofacies of the ostracod fauna which represent a deep-water environment. Therefore, these ostacods may have been transported from the shallow-water environment, most likely from the Yangtze carbonate platform. If this conjecture is the truth, then the Jiangshan District was near the shallow-water carbonate platform and received its sediments during the Darriwilian. It is still essential to do more work in the future to better understand the ecology of the Ordovician ostracod fanuas and their role in the sedimentary system of South China.
The Upper Ordovician Microfossil Assemblages from the Pagoda Formation in Zigui, Hubei Province
Ke Zhang, Aihua Yuan, Qinglai Feng
2018, 29(4): 900-911. doi: 10.1007/s12583-017-0958-7
The Pagoda Formation is a lithologically and biologically distinctive unit among the Upper Ordovician. The strata are characterized by a nodular limestone, which yields fossil assemblages of high diversity. Conodonts of 14 genera 20 species (6 undetermined species) and ostracods of 14 genera 26 species (16 undetermined species) are identified. In addition, spherical radiolarians and minute-walled foraminifers were first reported from this formation in South China. The conodont assemblage is attributed to the Hamarous europaeus Zone, which indicates the Early Katian Age. The conodont HDS biofacies, along with thin-shelled ostracods, spherical radiolarians and foraminifers, suggest relatively deep and quiet water depositional environment. Accordingly, these fossil materials not only enrich the diversity of the Pagoda biota, but also provide evidence for discussions of depositional environments and stratigraphic correlations for the Pagoda Formation.
New Siliceous Microfossils from the Terreneuvian Yanjiahe Formation, South China:The Possible Earliest Radiolarian Fossil Record
Shan Chang, Qinglai Feng, Lei Zhang
2018, 29(4): 912-919. doi: 10.1007/s12583-017-0960-0
Radiolarians form an important part of the planktonic realm in the ocean of Early Paleozoic, but their origin and evolutionary processes has long been enigmatic. The ancestral representatives of radiolarians have been considered to belong to the order Archaeospicularia, whose unquestionable fossil records were dated back to the Middle Cambrian. Here we report? Blastulospongia and unnamed spherical radiolarians in the Terreneuvian from the Yanjiahe Formation in Hubei Province, South China. Blastulospongia is an enigmatic siliceous microfossil genus, with affinities proposed amongst the radiolarian, sphinctozoan-grade sponges and uncertain protists. As for the newly discovered unnamed radiolarians, morphologically they possess latticed shell, spherical shape and are all small in size. Our discoveries support the idea that spherical radiolarians is an ancient representative, whose origin and diversification was probably much earlier than generally accepted. The hypothesis that the oldest radiolarians belong to the order Archaeospicularia needs to be re-examined.
U-Pb Geochronology, Elemental and Sr-Nd Isotopic Geochemistry of the Houyaoyu Granite Porphyries:Implication for the Genesis of Early Cretaceous Felsic Intrusions in East Qinling
Xiaohu He, Hong Zhong, Zhifang Zhao, Shucheng Tan, Weiguang Zhu, Siqi Yang, Wenjun Hu, Zhong Tang, Congfa Bao
2018, 29(4): 920-938. doi: 10.1007/s12583-018-0788-2
The Early Cretaceous Houyaoyu granite porphyries are located in the south margin of the North China Craton. Field observations, petrography, geochronology, major and trace elemental and Sr-Nd isotopic compositions are reported to elucidate the genesis of the Houyaoyu granite porphyries. SIMS zircon U-Pb analyses for the Houyaoyu granite porphyries yield two concordant ages of 133.2±2.3 (2σ) and 131±1.1 (2σ) Ma, respectively. Major and trace elemental compositions indicate that these porphyries are high-K I-type granites with high contents of SiO2, K2O, Rb, U, Pb, low Nb, Ta, Ti, and P. Initial 87Sr/86Sr ratios range from 0.708 3 to 0.709 7, and εNd(t) values range from -9.13 to -12.3, with corresponding two-stage depleted-mantle Nd model ages (T2DM) varying from 1.57 to 1.91 Ga. This suggests that the Houyaoyu granite porphyries were predominantly derived from ancient lower conti-nental crust, with minor involvement of mantle-derived components. On the basis of the tectonic evolu-tion of the Qinling Orogen and geochemical characteristics of the Houyaoyu granite porphyries, it is proposed that they were formed in an extensional tectonic setting related to lithospheric destruction of the North China Craton, and produced Mo and Pb-Zn mineralization in East Qinling Orogen.
Petrogenesis and Ore Genesis of the Late Yanshanian Granites and Associated Porphyry-Skarn W-Mo Deposits from the Yunkai Area of South China:Evidence from the Zircon U-Pb Ages, Hf Isotopes and Sulfide S-Fe Isotopes
Xinyu Wang, Zhen Yang, Nengsong Chen, Rui Liu
2018, 29(4): 939-959. doi: 10.1007/s12583-017-0901-1
There are a wide range of magmatism and mineralization in the Yunkai area of South China during the Late Yanshanian Period, including the newly discovered Michang, Youmapo, Sanchachong and Songwang porphyry-skarn W-Mo deposits. In this study, we obtained zircon U-Pb ages of the ore-bearing biotite granites and their mafic enclaves from 88±1 to 110±1 Ma. Zircons from the granites show Hf isotopic compositions with negative εHf(t) values of -5.9 to -0.6 and calculated Hf model ages (TDM2) of 1.5-1.2 Ga; indicating that the Middle Proterozoic crustal materials may have provided an important source for the magmatic rocks in this district during the Late Yanshanian Period, whereas zircons from the mafic enclaves show positive εHf(t) values of 1.3 to 10.1 with younger Hf model ages (TDM2) of 0.5-1.1 Ga, suggesting a mantle component may have involved in the granitic magma generation. Sulfur isotope study of the sulfide minerals from the W-Mo deposits show a narrow δ34S distribution with most data ranging from -4.2‰ to 5.2‰. In addition, this study reports the first Fe isotopic compositions of pyrite in the W-Mo deposits, which show a uniform distribution range with the values near zero (δ56Fe=0.16‰-0.58‰, average 0.35‰; δ57Fe=0.02‰-0.54‰, average 0.48‰). These data indicate that the ore-forming materials may come from the deep-sourced granitic magma, and the mineralizations show a close relationship with the granitic magmatism during the Late Yanshanian Pe-riod. Combining with previous results, we suggest that there is a widespread porphyry-skarn W-Mo mineralization in the Yunkai area during the Late Cretaceous (80-110 Ma), which has a close relation-ship with the Late Yanshanian magmatism that may have formed during the rollback of the subducted Pacific Plate.
Two-Dimensional Ground Deformation Monitoring in Shanghai Based on SBAS and MSBAS InSAR Methods
Shaochun Dong, Sergey Samsonov, Hongwei Yin, Lulu Huang
2018, 29(4): 960-968. doi: 10.1007/s12583-017-0955-x
Shanghai has experienced the greatest land subsidence in China in the past sixty years and produced undesirable environmental impact. However, horizontal ground deformation has not been understood yet. Therefore ground deformation monitoring together with the analysis of its driving forces are critical for geo-hazards early-warning, city planning and sustainable urbanization in Shanghai. In this paper, two-dimensional ground deformation monitoring was performed in Shanghai with SBAS and MSBAS InSAR methods. Twenty-nine Multi-Look Fine 6 (MF6) Radar-sat-2 SLC data acquired during 2011-2013 were used to derive vertical ground deformation. Meanwhile, six descending Multi-Look Fine 6 (MF6) and four ascending Multi-Look Fine 2 (MF2) spanning April to August, 2008, were used to derive vertical and horizontal ground deformation during the observation period. The results indicate that vertical and horizontal deformations in 2008 were not homogeneously distributed in different districts ranging from 0-2 cm/year. Vertical de-formation rate during 2011-2013 were decreased to less than 1 cm/year in most district of Shanghai area. Activities from groundwater exploitation and rapid urbanization are responsible for most of the ground deformation in Shanghai. Thus, future ground deformation in vertical and horizontal directions should be warranted.
Temporal and Spatial Variations of Microbial Carbon Utilization in Water Bodies from the Dajiuhu Peatland, Central China
Rui-Cheng Wang, Hong-Mei Wang, Xing Xiang, Yu Gao, Qing-Wei Song, Lin-Feng Gong
2018, 29(4): 969-976. doi: 10.1007/s12583-017-0818-5
To investigate the microbial utilization of organic carbon in peatland ecosystem, water samples were collected from the Dajiuhu Peatland and nearby lakes, central China across the year of 2014. The acridine orange (AO) staining and Biolog Eco microplates were used to numerate microbial counts and determine the carbon utilization of microbial communities. Meanwhile, physicochemical characteristics were measured for subsequent analysis of the correlation between microbial carbon utilization and environmental factors. Results indicated that total microbial counts were between 106-107 cells/L. Microbial diversities and carbon utilization rates showed a similar pattern, highest in September and lowest in November. Microbial communities in the peat pore waters preferred to utilize N-bearing carbon sources such as amines and amino acids compared with microbial communities in lakes. The network analysis of microbial utilization of 31 carbon substrates clearly distinguished microbial communities from peat pore waters and those from lakes. Redundancy analysis (RDA) showed the total organic nitrogen content (P=0.03, F=2.5) and daily average temperature (P=0.034, F=2.4) significantly controlled microbial carbon utilization throughout the sampling period. Our report is the first one to address the temporal and spatial variations of carbon utilization of microbial communities which are closely related to the decomposition of organic matter in the Dajiuhu Peatland in context of climate warming.