Isotope Geochemical Characteristics and Material Sources of Tin--Bearing Porphyries in South China

Tin-bearing porphyries in South China can be divided into the F-rich and F-poorsubtypes. They are high-silica (SiO_2>71%), peraluminous (A/NKC>1.0) and rich inincompatible elements (Rb, Zr, U, W, Sn) and have weak Ce (δCe=0.68-0.82) and strong Eu(δEu=0.01-0.38) negative anomalies. Meantime, they also have low δ_(Nd)(-6.3- -8.4), high~(207)Pb/~(204)Pb (15.588-15.790), medium to high (~(87)Sr/~(86)Sr)_i (0.7084-0.7287) and relatively highδ~(18)O(9.1-10.3‰). These characteristics clearly suggest that the two subtypes of tin-bearingporphyries were derived from the crustal materials. Their differences lie only in the existence ofcertain different components in their source materials. Therefore, there is only one type oftin-bearing prophyry in South China. that is continental crust transformation type.     

Chengdeite-A New Mineral of Ordered Natural Iron-iridium Alloy

Chengdeite occurs in chromite orebodies in dunite as well as in placers in their neighbourhood. The mineral occurs as granular aggregates in association with inaglyite and in some cases occurs as graphic intergrowths with native iridium. It is opaque with a metallic lustre, colour steel-black, streak black,HM = 5.2, VHN50=452 kg/mm2, cleavage not observed, fracture not observed, strongly magnetic. Its reflection colour is bright white with a yellowish tint. It has no internal reflection, bireflectance or pleochrism, and shows isotropism.Thirteen chemical analyses were carried out by means of the electron microprobe. The mean percentages of the data obtained in the 13 analyses ares S 0.001, Fe 7.9, Ni 0.03, Co 0.03, Cu 0.83, As 0.02, Rh 0.19, Pd 0.00, Os 0.06, Ir 88.5, Ft 2.2 and Pb 0.00. The simplified formula is Ir3Fe, which requires Ir 91.17 and Fe 8.83, the total being 100.00 (% ).Five strongest lines of X-ray powder diffraction (hkl, d, I)are: 111, 2.18 (80);200, 1.89 (60); 220, 1.34 (70);311, 1.142     

The Palaeomagnetic Study of the MineralizationAge of Gold Deposits in the Xiong'' ershan Area,Henan Province

Based on palaeomagnetic studies of the Precambrian gold deposits in the Xiong'ershan area, Henan Province, the authors infer that the ore-forming processes of the Beiling alteration-type gold ore deposit and the Dianfang breccia-type gold ore deposit started in the Proterozoic, and was superimposed by later mineralization, whereas the mineralization age of the Jiguanshan quartz- vein type gold ore deposit is Yanshanian.     

The Arcuate Nappe Structure on the Northern Margin of the Wuliang Moutnains in Western Yunnan

The arcuate nappe structure on the north edge of the Wuliang Mountains in westernYunnan Province is a complex nappe structural system with multiple superimposed structures.The autochthonous system is a WNW-trending arcuate fold belt consisting of the Jurassic andCretaceous and the allochthonous system is mainly composed of Upper Triassic rocks. Generally,the nappe structure moved from south to north, with the hanging wall thrusting in a WNW direc-tion for a distance of over 10km. The deep nappe structural system was formed at depths ofabout 5-10km in an environment not exceeding the greenschist facies. It occurred in theOligocene (about 40-20 Ma).     

A Study of Sedimentary Environment and Reservoir Quality of the Carboniferous Donghe Sandstonein the Tarim Basin

Very thick, fine-grained quartzose sandstone of the Lower Carboniferous (called the Donghe sandstone) was discovered in Donghe-1 well in the Tarim basin. Highly-productive commercial oil and gas flows were obtained when a well completion test was conducted. This important discovery proved that the quartzose sandstone is a prospecting target with good prospects. After that, other two paying oil and gas flows were found in the Lower Carboniferous in the Tazhong-4 and Tazhong-10 structures (Tazhong means central Tarim), equivalent to the Donghe sandstone. The Tazhong-4 structural oil field is the biggest oil field ever discovered. Therefore it is of guiding importance in oil and gas exploration to deepen the study of sedimentary and reservoir features and the sedimentary environment of the Donghe sandstone and to build a sedimentary model in order to understand the reservoir distribution pattern.     

Outcrop Sequence Stratigraphy of Neoproterozoic in Hunjiang Area, Jilin Province

TheNcoproterosoiciswelldevelopedinHUnjiangarea,JinnProvince,andarecomposedoftheMadaling,Baffongh,DiaoyUtaiformationsoftheQingbaikouSyStemandtheNanfen,Qiaotou,Waulong,BadaojiangandQinggoUZifonnationsoftheSilvanSyStem.In1992,aresearchofsequencestratigraphywasdonethereforthefirsttime(GaoandQiao,1992).Since1993,duringthemappingofif50on,outcropsequenCestratigl'aphyhasfatherstudiedtherebrig.l).~ENCE~NDARYTheconceptofdepositionalsequencelicitedbyupperandloadunconfondtywaspointedoutbySlo…     

Late Permian-Middle Triassic Sea Level Changes of Yangtze Platform

INTRODUCTIONTheformationofthePangaeainthePenmangreatlyreducedthedimensionofshelf,sothelateStPenmanmarinesedimentaryrecordsespeciallythatofshallowsea,arelackinginmostpartSoftheworld,exceptthatsomeareasaroundthePaleo--TethySrecordedthecontinuousdepositionacrossthePenmanandTriassicboundary(Schopf,1974).DLiringthattimeYangtzewasablockoverWhichcoveredthelargestshallowshelfofthePenman--Triassicinterval,wherethemostcompletesedimentaryrecordofthatintervalispreserVed(Yangetal.,1993).Itisund…     

Sequence Boundary and Sea Level Changes in Western Margin of Upper Yangtze Platform during Permian and Triassic

TECTONICac~ac~~RA~m~NERGoorU~YANG~~oafNdsreof~actTheho~ofUPperYangtzePlatformwascpetallizedandconsolidatedinthekiaogUanhernovernentofMeSoproterocoic(ca.1700mp.ItconstituteSthestableCentralSichuanconiinelhalnucleusandthecratonakin.Therearetabtabofcontinental~ionsurroUndingtheCentralSichuanconti~alnuCleusduring1700--800the.ThebordersofthecontinentalaCCretionareconcordantacthebordersof~nicandPalcogngnphy,andalsofo~theboundarybet~basin~formationS.InPaloocoic,tab~nicCycleScormspond…     

ECONOMIC GLOBALIZATION AND ITS IMPACTS ON URBAN SYSTEM IN CHINA

Tl1eincreaseindomeSticmarkotalonecouldnotachieveeconon1icgrowthti1atChinaexpenencedinthel98os.Chinahasanaverageannualgrowthrateofl4.3perwtinthepenodofl978-l99o,whichisoneofthehighestinAsiaandtheworId.Sucl1highecononticgrowthhasbamachievedthrougheconon1icrefon11sandglobalizationofitseconomy.TheglobaliZationofitseconon1yisanintentionaleffortoftheopa1policyadoPtedinl978.BecauseofthelrlOCationaladvantage,itisnotsuI`Prisingtofindthateconomicgrowthofthecoastalprovincesisfasterthanililandprovince…     

THE HISTORY AND STATUS OF GEOPOLITICS AND THE GEOPOLITICAL STRATEGIES OF CHINA

LTlewe~jk~inGeop0uticsbeofiticaisonOfthemoStimPoatbranchesofp0liticalmpaphylnhumanmpaphyThssmpatQfbeoliticshasundeIgOneafewhmes0frisinganddeCirung.SOInetilnesthewiodhaSbonfoedfavourinsomempphers'eyeS,butin0therhmesithasbangiventheedd~and~atargaOfathousandarrowsbyanOtherppaphers.Thetenninationof,the8aredW0rldWarandthedeadofK.HaushofermeantheendofGermangcopolihcal~anditalsoledtothedeCiningOfGapolihcsinaratherlOngtime.Inabout30yearsfromthel940stol977,wboC.Graypublishedhisfamousbookenti…