Chief Editor:HOU Zengqian
Governing Body:China Association for Science and Technology
Organizer:Geological Society of China
start publication :1922
ISSN:ISSN 1000-9515
CN:CN 11-2001/P
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Xu Shutong , Jiang Laili , Liu Yican , Zhang Yong Institute of Geological Sciences of Anhui Province , Hefei , Anhui Sun Sheping
1992, 66(3).
Abstract:The Dabie Mountains are believed to be a collisional orogenic belt between the Yangtze amd Sino-Koreancontinental plates. It is composed of the foreland fold-thrust zone, the subducting cover and basement of theYangtze continental plate, the coesite- and diamond-bearing ultra-high pressure metamorphic zone and themeta-ophiolitic melange zone in the subducting basement, the fore-arc flysch nappe and the back thrust zoneoccurring respectively on the southern and northern margins of the Sino-Korean continental plate and the in-herited basin with molassic deposits on the northern margin. When the palaeo-Dabie oceanic plate subductednorthward in the Early Palaeozoic, volcanic arc and back arc basin probably formed on the southern margin ofthe Sino-Korean continental plate. The Sm / Nd isotopic dating of the strata and eclogite which were drawn in-to the foreland fold-thrust zone indicates that the intense collision of the two continental plates took place inthe Early Mesozoic.
Dong Zhenxin Geological Museum of China , Beijing Fei Zhenbi
1992, 66(3).
Abstract:The author studied the grain size, shape, colour, altered coat, mineral species, chemical composition,end- member components and infrared spectra of clinopyroxenes occurring as megacryst, macrocryst andgroundmass minerals, intergrowths with pyrope and ilmenite and minerals in deep-seated xenoliths and inclu-sions in diamonds in kimberlites of China. The clinopyroxenes under study were compared with megacrystclinopyroxenes in basalts and minerals in their deep-seated xenoliths and clinopyroxenes in lamproites andminettes. The coexisting clinopyroxene-pyrope pair was studied. Besides the author also studied the origin ofclinopyroxenes in kimberlites, P-T conditions for their formation and their reflected tectonic environments ofthe kimberlite formation. He suggests that this mineral is an indicator for diamond exploration.
Ding Tiping , Liu Yushan , Wan Defang , Liu Zhijian , Li Jincheng , Zhang Guilan Institute of Mineral Deposits , Chinese Academy of Geological Sciences , Beijing
1992, 66(3).
Abstract:Experiments for oxygen isotope exchange between ferberite and water were carried out and the followingequation on oxygen isotope fractionation between ferberite and water against temperature was obtained:Combining this equation with the equation of Clayton et al. (1972) on oxygen isotope fractionation be-tween quartz and water, an equation on oxygen isotope fractionation between quartz and ferberite was ob-tained:The Bigeleison-Mayer function method was used to calculate the oxygen isotope fractionation betweenquartz and ferberite. The theoretical curve obtained agrees with the experimental calibration results quite wellin the temperature range of study.The above calibrated equation has been used in 5 world famous tungsten deposits to determine their tem-peratures of formation. The results show that the temperature range for an idividual deposit determined by thisgeothermometer agrees with those obtained from fluid inclusion determination and other isotopegeothermometers.
Xing Fengming , Xu Xiang , Chen Jiangfeng , Zhou Taixi , K.A. Foland Institute of Geological Sciences of Anhui Province , Hefei , Department of Earth , Space Sciences , University of Science , Technol ogy of China , Hefei , Department of Geology , Mineralogy. the Ohio State University , Columbus , OH , USA Jiang Minxi
1992, 66(3).
Abstract:The newly obtained Sm-Nd isochron ages are 1034 Ma and 935 Ma for ophiolites from northeasternJiangxi and Fuchuan, southern Anhui respectively. There exist two unconformity surfaces under the initialLate Proterozoic volcanics as well as the Sinian rocks. The Xiuning intrusive body which was intruded into theShangxi Group in southern Anhui yields a whole-rock Rb-Sr isochron age of 963 Ma. There occurs a belt ofLate Proterozoic calc-alkali volcanic rocks extending from northeastern Jiangxi to northwestern Zhejiang. Inthe light of the above facts, the authors consider that the southeastern margin of Jiangnania is an ancient islandarc. At about 1000 Ma ago, the Huanan (South China) oceanic crust was subducted along the line linking Dex-ing and Hangzhou, thus starting the accretion of the island arc system to Jiangnania. At 800 Ma ago Cathaysiaand Jiangnania converged together along the Jiangshan-Shaoxing line, marking the end of the accretion.
Liu Junying , Chen Zhongliang Institute of Geology , Chinese Academy of Geological Sciences , Beijing Panxi Geological Party , Sichuan Bureau of Geology , Mineral Resources , Xichang Liu Linqun
1992, 66(3).
Abstract:This paper describes the fossil charophytes collected from the Late Triassic Xujiahe Formation in Dazuand Early Jurassic Lower Yimen Formation in Xichang, Sichuan Province, and their significance. Up to now,papers dealing with fossil charophytes of the Late Triassic, especially of the Early Jurassic, have been rarelypublished. The description of the two new species of Porochara, P. dazuensis and P. xichangensis, and theirfossil assemblage not only provides an important basis for classification and correlation of red beds insouthwestern China but reveals for the first time the features of the charophyte flora of the Late Triassic-EarlyJurassic in the area, thus offering valuable data for the establishment of Triassic and Jurassic charophyte fossilzones in China.
Li Peiying , Cheng Zhenbo , Lu Houyuan , Liu Guohai First Institute of Oceanography , SOA , Qingdao , Shandong Liaoning Teachers University , Dalian , Liaoning Liu Linqun
1992, 66(3).
Abstract:This Paper discusses the origin of the Coastal Zone Loess on the Liaodong Peninsula, Liaoning Province.The loess is composed mainly of proximal materials transported by low-altitude air flow and less commonly ofinland distal materials carried by high-altitude air flow. The main provenance is the Liaodong Bay. When thesea level declined during glacial period, the bottoms of the Liaodong Bay and Bohai Sea emerged, wheredesertization occurred. As a result, submarine sediments were transported by strong northwesterly winds to theeastern coastal zone of the peninsula and deposited there. These materials mixed with the windblown dust car-ried by atmospheric circulation from the interior of the continent, forming the loess.
Wang Anjian Changchun University of Earth Sciences , Changchun , Jilin
1992, 66(3).
Abstract:High in sodium and low in potassium (Na_2O/ K_2O>1), the charnockitic gneiss series in theSantunying- Taipingzhai area, eastern Hebei province, consists of hypersthene- quartz- diorite,hypersthene-granodiorite and hypersthene-plagioclase-granite. Geological, petrological and large ion lithophileelement(LILE), high field strength element (HFSE) and REE geochemical studies suggest that themedium-coarse-grained hypersthene-granodiorite is the product of crystallization of anatectic magmas of thesame composition. Under granulite facies conditions, the equilibrium crystallization differentiation of themagmas yielded the early crystallization phase-high-SiO_2, LILE-depleted, low-∑REE, positive Eu anomalyand REE- saturated hypersthene- plagioclase- granite. The residual phase, coarse- grained to pegmatitichypersthene- granodiorite, is marked by low SiO_2, LILE-enrichment, high ∑REE and REE-undersaturation.These rocks and hypersthene-quartz-diorite enclaves constitute the sodium-charnockitic gneiss series in easternHebei province. Model calculation for trace elements in the granitoids was applied. On the basis of a systematicgeological study, the equation for calculation was chosen, the source magma was determined and the partitioncoefficients were obtained. The resulting curves are entirely consistent with those observed in the patterns of ac-tual rocks. The study indicates that whole-rock REE patterns can not be used directly in the comparison of thesources and genesis of granitoids.
Chief Editor:HOU Zengqian
Governing Body:China Association for Science and Technology
Organizer:Geological Society of China
start publication :1922
ISSN:ISSN 1000-9515
CN:CN 11-2001/P