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2002 Vol. 13, No. 1

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Triassic Collisional Structures and Post Collisional Deformation of Bixiling UHP Rock Stack: Insights for Tectonic Evolution of UHP Metamorphic Belt in Dabie Massif, Central China
Suo Shutian, Zhong Zengqiu, Zhou Hanwen, You Zhendong
2002, 4(1)
Abstract:
Detailedthree~dimensionalstructuralstudiesindicatethattheBixilingarea,Dabiemassif,centralChinashowsthedeepestexposedlevelsoftheorogenicwedgeformedduringtheTriassicYangtze~Sino~Koreancontinentalcollision.New1∶10000scalestructuralmapping,combinedwithdetailedpetrologicalanalysisinthisarea,hasenabledustoaccuratelydistinguishstructuresrelatedtotheTriassiccontinentalcollisionfromthoserelatedtopost~collisionaldeformationintheultrahighpressure(UHP)metamorphicunit.Thecollisionalorcompressionalstructuresincludethemassiveeclogitewithaweakfoliation,foliatedeclogiteorUHPductileshearzones,aswellasupperamphibolitefaciesshearzones,whereasthepost~collisionaldeformationischaracterizedbyaregionally,flat~lyingfoliationcontainingstretchinglineationsandcommonreclinedfolds.Theformerispresentexclusivelyintheeclogitelensesandtheirmargins,representingorogenicthickeningorsyn~collisionalevents,whilethelatterwasbestoccurredonvariablescalesunderamphibolitefaciesconditions,showingsub~vertical,extremeshorteningandductilethinningofthemetamorphicrockstack.Theeclogitefaciestectonitesthathaveamarkedfabricdiscordancetothepenetrativeamphibolitefaciesextensionflowfabricarecommon.Itisemphasizedthatanextensionaltectonicsettingfollowingthecollision~orogenicthickeningstagewas,atleastpartly,responsibleforexhumationoftheUHPmetamorphicrocksintheDabiemassif.AnewtectonicevolutionmodelisproposedfortheUHPmetamorphicbeltonthescaleoftheDabiemassif.TheBixilingareathusprovidesawindow,fromwhichthedynamicprocessesconcerningtheformationandexhumationoftheUHProckscanbeobserved.RegionalstudiesintheDabieMountainshaveconfirmedthisinterpretation.
Intraplate Deformation of Asia Derived from ITRF2000 Velocity Field
Jin Shuanggen, Zhu Wenyao
2002, 4(1)
Abstract:
Thedefinitionofan“intraplatefixed”frameremainsasignificanterrorsourceforcrustalmotionstudiesatafewmillimetersperyearlevel.Anappropriateimplementationofsuchaframeisveryimportanttoavoidbiasedvelocitiesandtoconfirmavalidgeophysicalinterpretation.Here,weestablishthenewestglobalplatemotionmodelofITRF2000VELandresearchthedefinitionofanAsian~fixedframeinAsiausingtheITRF2000velocityfield.Byχ2andFratiotests,wefindasubsetsiteinAsiathatsatisfiesarigidcaprotationwithresidualvelocities<0.95mm/aandprovideastableAsiareferenceframe(SARF).Inthisreferenceframe,wefindresidualvelocitiesatAsiaticITRF2000sitesthatareconsistentwithknownactivetectonicfeature.Animportantresultofthisstudyistheidentificationofinternaldeformationoftheorderof1~2mm/ainanareausuallyinterpretedas“stable”Asia.Theseresultsshouldbefurthercheckedasnewer,denserandmoreaccuratespacegeodeticdatasetswithlongerobservationtimespan,whichbecomeavailableforAsia
Growth of Emerald Crystals by Evaporation of Na2O~MoO3 Flux
Oishi Shuji, Yamamoto Hirofumi, Suzuki Takaomi
2002, 4(1)
Abstract:
Well~formed crystals of emerald, Be3Al2Si6O18 ∶ Cr, were easily grown from an Na2O~MoO3 flux by an isothermal technique. The crystal growth was conducted by heating a mixture of solute and flux at 1100 ℃ for 24h. The evaporation loss of flux depended on the amount of Na2O added to MoO3. Emerald crystals of lengths up to 2.1 mm and widths of 1.4 mm were grown. The crystal sizes were dependent on the evaporation loss of the flux. The obtained crystals were transparent and exhibited the typical emerald~green color. The form of the emerald crystals was a twelve sided prism bounded by well~developed faces. The aspect ratios were in the region of 1.4 to 2.3. The density was (2.64±0.02) g/cm3. The IR absorption bands were in good agreement with the literature data.
Uppermost Permian Radiolarian Biostratigraphy of Southern Guizhou, Southwest China
Gu Songzhu, Feng Qinglai
2002, 4(1)
Abstract:
With abundant deep~water upper Permian sediments, Guizhou is an ideal place for the research of radiolarian biostratigraphy of Upper Permian. The sections of Sidazhai and Lekang in southern Guizhou Province are studied. Lithology and biostratigraphy of the siliceous rock sequence of uppermost Permian in the two sections are introduced. Radiolarian assemblage zones, Neoalbaillella optima assemblage zone and Klaengspongus spinosus assemblage zone in ascending order are established for the topmost Permian of southern Guizhou. The Klaengspongus spinosus zone has been the topmost radiolarian assemblage zone of Permian, which is also correlated with former ones in a considerable depth.
Geochemical Properties and Stratigraphical Correlation of Frasnian~Famennian Transitional Strata in Wuzhishan Section
Wang Chaoyong, Xia Wenchen
2002, 4(1)
Abstract:
ThequalitiesofpetrologyandpaleobiologyinWuzhishanSectionarestudied.Severalgeochemicalanomaliesarerecognized,suchas:highrareearthelementcontent,highpyritecontentandNianomalies.ItcouldbecorrelatedwithNandongSectioninXiangzhouCountyandtheF/FboundarycouldbedeterminedaccordingtoNianomalies.Theresultsofthestudyindicatethatthegeochemicalanomalyplaysanimportantroleinstratigraphiccorrelationinnon~fossilstratum
Au (Cu) Ore Fluid Dynamics in Bordering Orogenic Belt of Simao Nanping Basin, Yunnan Province
Cao Zhimin, Zheng Jianbin, Xu Zemin, Li Baohua, Qin Gongjiong
2002, 4(1)
Abstract:
The paleohydrogeologic condition and the tectonic stress field during the mineralization epoch of the Au (Cu) ore fluid in the bordering orogenic belt of Simao~Nanping basin reveal that the complicated paleohydrodynamic condition during the Devonian Carboniferous period in the northern Ailao~shan was favorable for the pre~enrichment of the mineral elements, and that the migration and the distribution of the groundwater were controlled by the tectonic stress field and driven by temperature and hydraulic gradients during the Yanshan~Himalayan movement epoch. Therefore, the determination of the low~pressure zone of the maximum principal stress is effective for the location of the Au deposits (ore spots)
Desertification Risk Monitoring for North Shaanxi Province, China,Using NormalizedDifference Vegetation Index
Mushtak Talib Jabbar
2002, 4(1)
Abstract:
In this study, the remote sensing is applied to the examination of the relationship between desertification and normalized difference vegetation index (NDVI) in the context of northern Shaanxi Province. This relationship is also examined using spatial analysis methods. A strong negative correlation is found in the largest area desert, indicating that the relationship between desert and NDVI is not a simple linear one and that the correlation coefficient between NDVI and vegetation abundance is significant. The normalized difference vegetation index (NDVI) was compared with other vegetation index based methodologies. NDVI is a valuable first~cut indicator for such systems, although the analysis and interpretation of its relationship to desertification are complex and also based on the detailed analysis of its relationship to ecological zone, vegetation type and season. Conclusions thus made would help to upgrade the methodology as an effective tool for early~warning desertification in the northern Shaanxi Province where a drought is a recurring threat. This methodology includes the integration of NDVI with other socio~economic and bio~physical indicators in GIS, the complementation of desert area data with satellite data, and the analysis of the relationship between NDVI and specific climatic zones, for each season and vegetation type
Sand Dunes Fixation in Baiji District, Iraq
Ayad Mohammed Fadhil
2002, 4(1)
Abstract:
ThisstudywascarriedoutatSandDunesStabilizationResearchesStationinBaijidistrict(230kmnorthofBaghdad,Iraq)toevaluatetheeffectsoflocalsoilconditionersmanufacturedfromoilderivativesandplantresidualsonsanddunesfixationasthefirststepforsanddunesstabilization.Theresultsindicatethatthefueloilhasthefirstplaceinimprovingwinderosionparametersinthestudyarea,suchasincreasingmeanweightdiameter,dryaggregatespercentage,theneededtimeforcompletedisaggregationbydrysieving,anddecreasingthedisaggregationrates.Bitumenemulsionoccupiesthesecondplace,whiletheplantresidualsoccupiesthethirdplaceandhasslighteffectsonthestudiedparameters.Effectsofconditionersonnaturalvegetationcoverarenegativeinoilderivativestreatments,whilepositiveinplantsresidualstreatments
Pyrite Oxidation in Leaching Process of Radionuclides and Heavy Metals from Uranium Mill Tailings
Ma Teng, Wang Yanxin, Xu Lechang
2002, 4(1)
Abstract:
Pyriteisasensitivemineralinthegeologicalenvironment,anditsoxidationproducesanimportantgeochemicalandenvironmentaleffectonthecontroloftheredoxandpHconditions.Columnexperimentresultswereusedformodelingthegeochemicalprocessesinuraniummilltailingsunderleachingconditions.Oxidationofpyritedominatesthecontrolofthetailingsleachingprocess.Theexperimentalandmodelingresultsshowthattheleachatechemistrychangessubstantiallywiththedecreaseinpyriteconsumption.Intheinitialstageoftheleachingexperiment,thepyriteisconsumedseveralhundredtimesgreaterthanthatinthelaterstages,formuchmoreoxygenispresentinthetailingsintheinitialstage.Astheexperimentcontinues,thetailingsisgraduallysaturatedwithwaterandtheoxygenconcentrationgreatlydecreasesandsodoespyriteconsumption.Theexperimentalandmodelingresultsareusefulforthedesignofmilltailingdecommissioning:oxidationprocessandtransportofradioactivenuclidesandheavymetalscanbeconstrainedbycontrollingtheoxygenconcentrationoftailingsandtheinfiltrationofmeteoricwater.
Study on Deep Well Dewatering Optimization Design in Deep Foundation Pit and Engineering Application
Hu Chunlin, Yang Huijun
2002, 4(1)
Abstract:
Basedonanalysesofthetheoriesofgroundwaterunsteadyflowindeepwelldewateringinthedeepfoundationpit,Theisequationsarechosentocalculateandanalyzetherelationshipbetweenwaterleveldrawdownofconfinedaquiferanddewateringduration.Inordertoreduceengineeringcostanddiminishdetrimentaleffectonambientsurrounding,optimizationdesigntargetfunctionbasedonthecontrolofconfinedwaterdrawdownandfourrestrictionrequisi tionsbasedonthecontrolofsafewaterlevel,resistancetothrowingupfromthebottomoffoundationpit,avoidingexcessivelygreatsubsidenceandunequalsurfacesubsidenceareproposed.Adeepwelldewateringprojectinthedeepfoundationpitisoptimallydesigned.Thecalculatedresultsincludingconfinedwaterleveldrawdownandsurfacesubsidenceareincloseagreementwiththemeasuredresults,andtheoptimizationdesigncaneffectivelycontrolbothsurfacesubsidenceoutsidefoundationpitandunequalsubsidenceasaresultofdewatering.
Discrete Element Analysis of Huangtupo Landslide
An Guanfeng, Yin Kunlong, Tang Huiming
2002, 4(1)
Abstract:
OnthebasisofthedeepgeologyandthegeologicalstructureofHuangtupolandslide,anancientlandslideinthereservoiroftheThreeGorges,thegeo~environmentalmodelofthelandslideisestablishedtoanalyzequantitativelytheslidingmechanismbyusingthediscreteelementmethod.Itisconcludedthatinterbeddingstructureofsoftandhardformationconsistsofthemaingeologicalbackground,whichinducedthearchingoftheformationundergravity.Stabilityanalysisofdifferentloadingsshowsthatthegroundbuildingweightonthemiddleslopemayrestraintheextensionofshearslidingzonebelow,butmayactivatethefootareawhichwillreducethesafetyfactorofthefront.
CCSD Well Logging Engineering Program
Pan Heping, Niu Yixiong, Wan Wenxian
2002, 4(1)
Abstract:
ThispaperintroducesbrieflythetasksandcharacteristicsofChinaContinentScienceDrilling(CCSD)WellLoggingEngineering,theloggingmethodsmeasuredwithCCSD,thequalitycontroloforiginallogginginformation,theloggingplanofCCSD,theloggingengineeringmanagementofCCSD,thelogginginterpretationandtheresultsandreportsmadewithCCSD.
Effective Elastic Thickness of Southeast Part of Arctic Ocean-Eurasia Continent-Pacific Ocean Geoscience Transect
Yuan Bingqiang, Yvette H Poudjom Djomani, Wang Ping, Yuan Xuecheng, Zuo Yu
2002, 4(1)
Abstract:
Study on Folds of Equal Thickness Multi-layer Sandwiched in Different Thickness Media
Ye Bailong, Yu Ainan, Ouyang Jiantao
2002, 4(1)
Abstract:
The theoretical model and non~homogeneous differential equation of equal thickness multi~layer folds sandwiched in different thickness and same character media are established by elastic and plastic mechanics. The special answer of the non~homogeneous differential equation and the common answer of the homogeneous differential equation are deduced by applying logistic equation and special function, and the dominant wavelength theory of equal thickness multi~layer folds sandwiched in different thickness and same character media. In addition, the experimental folding in both elastic and sticky materials proves the dominant wavelength theory. 
Discovery of Enclaves from Cenozoic Pulu Volcanic Rocks in West Kunlun Mountains and Its Geological Implication
Zhang Zhaochong, Xiao Xuchang, Wang Jun, Wang Yong
2002, 4(1)
Abstract:
In this paper, we present the occurrence and mineral components of the enclaves firstly discovered in the Cenozoic Pulu volcanic rocks in west Kunlun Mountains, and propose that the enclave is accumulated by fractional crystallization within high~level magma chamber. In addition, the chemical compositions of its primary magma are calculated. The calculated compositions are similar to those of the Kangxiwa volcanic rocks that belong to the same volcanic belt in the Pulu volcanic region, suggesting their origin from the same source region. However, the temperatures and oxygen fugacity of magmas at high~level magma chamber decreased along with fractional crystallization.