检索结果-南通市图书馆

geological EVOLUTION AND OROGENY OF EAST KUNLUN TERRAIN ON THE NORTHERN QINGHAI—TIBET PLATEAU

在线全文

学校读者我要写书评

暂无评论

地学前缘 2000年第S1期7卷 234-235页

作者： Xu Zhiqin, Yang Jingsui, Li Haibing(Institute of Geology, chinese academy of geological sciences, beijing 100037,china)

The East Kunlun terrain is located on the northern Qinghai—Tibet plateau, composed of the East Kunlun Mountain and the Qaidam Basin and bounded by the Qilian terrain on the north and Bayanhar—Songpan Ganze terrain on the south. It is regarded as a composite orogenic belt characterized by having developed superimposed ductile tectonic regimes reflecting the collision orogeny during Early Paleozoic and Triassic periods. It has also experienced transformation from ductile to brittle deformation caused by the post orogeny, since Jurassic after the formation of the East Kunlun Mountain and the Qaidam Basin. A Paleozoic subduction complex zone was recently recognized along the north border of the East Kunlun terrain from Da Qaidam to Dulan (Xu,et al, 1 999). It is composed of ophiolite (of Early Paleozoic age?), tectonic melange and very high\|pressure metamorphic rocks with eclogite (\%p\%=2 2GPa, \%t\%=720℃) (Yang,et al.,1998) and garnet\|peridotite (\%p\%=2 5GPa, t =83.℃). The Anyemaqin Triassic subduction complex zone trending in NWW\|SEE was developed along the eastern segment of the south border of the East Kunlun terrain. It is mainly composed of ultramafic and mafic rocks, pillow basalt, radiolaria\|bearing clastic rocks, tectonic melange and mylonite. The subduction complex zone contains a series of the southward overthrusting imbricated slices. Instead of this subduction complex zone, a 2 km\|wide sinistral strike\|slip ductile shear zone trending in E\|W was developed along the western segment. On the basis of macroscopic and microscopic studies on a series of structural sections, we divide the East Kunlun Mountain into four tectonic units as follows: (1) North Proterozoic Metamorphic Basement Zone; (2) South Early Paleozoic—Triassic Superimposed Fold Zone; (3. South Triassic Transpression Zone; (4) Anyemaqin Back\|Arc Decollement\|Thrust Zone.

关键词： East Kunlun terrain composite orogenic belt subduction compl ex zone transpression shear zone

Discussion on measurement and calculation principle of petrogenetic depth

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1999年第24期44卷 2293-2295页

作者： LU Guxian and LIU Ruixun Institute of Geomechanics , chinese academy of geological sciences , beijing 100081 , china Department of Geology, Peking University, beijing 100871, china Institute of Geomechanics Chinese Academy of Geological Sciences Beiing China Department of Geology Peking University Beijing China

Geologic and geophysical data certificate that lithosphere and its down rock behave as solid, therefore,it is better to measure petrogenetic and metallogenetic depth according to internal stress of solid states. Lithomechanic experiment found that the bigger the confining pressure, the bigger the tensile and shear strength of rocks,so rock can bear very high differential stress but it is not broken. Sibson put forward that the property of rocks under 10-15km of the surface changes from brittle to ductile (rather than from elastic to plastic). Rock with ductile de-

关键词： petrogenetic depth solid stress state tectono-original additional hydrostatic pressure rock strength.

PALEOMAGNETIC ESTIMATE OF THE MESOZOIC—CENOZOIC LATITUDINAL DISPLACEMENT OF TERRENES IN THE QINGHAI—TIBET PLATEAU AND ITS SIGNIFICANCE

在线全文

学校读者我要写书评

暂无评论

地学前缘 2000年第S1期7卷 325-326页

作者： Li Pengwu, Cui Junwen, Li Li(Institute of Geology, chinese academy of geological sciences, beijing 100037, china)

The Mesozoic—Cenozoic latitudinal displacement amounts of terranes (or blocks) in the Qinghai—Tibet plateau were calculated in paleomagnetism. These terranes (or blocks) include Tarim and Qaidam blocks, East Kunlun, Baryan Har, Qiangtang, Lhasa and Himalaya terranes. The calculated results are listed in table 1. These results show that:(1) There was the latitudinal displacement difference between central area and southwestern area in the Tarim southern margin since the lower Cretaceous. There was a southward latitudinal movement from the beginning of middle Jurassic or upper Jurassic (Zhou Qingjie, 1992). The northward movement amounts of the Tarim northern margin since the Paleocene are greater than that of the Tarim southern margin. Tarim southern margin has moved northward about 1100km since the Paleocene, Tarim northern margin has done about 1700km. Qaidam has moved northward about 3.00km since lower\|middle Jurassic. The northward displacement amount of Qaidam since Paleocene is about 810km, near to that of the central area, Tarim southern margin.

关键词： Qinghai\|Tibetan plateau paleomagnetism latitudinal displacement

A New Scheme for Calculating Mineral End-Members With Reference to Clinopyroxene And Garnet

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1992年第2期66卷 191-196页

作者： Yang Jianjun Yang Jianjun Lithospheric Research Centre. chinese academy of geological sciences, beijing Jiang Minxi Lithospheric Research Centre Chinese Academy of Geological Sciences Beijing

In order to eliminate the defect of successively separative calculations of different end-members of a min-eral and to establish a widely applicable new scheme for calculating mineral end-members, the use of the linearprogramming technique is proposed to calculate simultaneously all end-members in this paper. All calculationswith the scheme under study can result in non-negative values. In the case of calculating end-members ofclinopyroxene, the Eskola's molecule is introduced so as to reach stoichiometry. When certain minor elementsin solid solutions are present in a remarkable amount, by adding to the equations the vectors of the corre-sponding end-members and adjusting the component vectors it is possible to obtain calculation results, in-cluding those of such end-mempbers. The possibility of using the calculation scheme under study to estimate theFe^(3.)/Fe^(2+) ratio of a mineral from electron microprobe analysis is also discussed in this paper.

关键词： CRYSTAL-CHEMISTRY

Kaolin Deposits of Weathering-Residual in the Coastal Area of Guangdong Province

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1991年第3期65卷 289-305,340页

作者： Zhou Guoping Lin Yuchuan Institute of Mineral Deposits, chinese academy of geological sciences, beijing,Center of geological Analysis of Guangdong Province, Guangzhou Institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing China

Kaolin deposits of weathering-residual type make up a large proportion in different types of kaolin depos-its and are widely used in ceramics, electron ceramics, rubber and paper industries. This paper discusses sys-tematically this type of kaolin deposit with respect to their features of occurrence, mineralogical and chemicalcomposition and transformation of minerals during supergene processes, thus providing some basic data forthe rational exploitation and utilization of the kaolin resources.

关键词： Kaolin Deposits of Weathering-Residual in the Coastal Area of Guangdong Province

Variation of terrestrial ecosystem recorded by stable carbon isotopes of fossils in northern china during the Quaternary

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2002年第1期47卷 76-78页

作者： DENG Tao, DONG Junshe & WANG YangInstitute of Vertebrate Paleontology and Paleoanthropology, chinese academy of sciences, {3. 100044, china laboratory of Palaeobiology and Stratigraphy, chinese academy of sciences, Nanjing 210008, china Department of Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences laboratory of Palaeobiology and Stratigraphy Chinese Academy of Sciences Department of geological sciences Florida State University

Stable carbon isotopes of C3.and C4 plants have completely distinct δ13. values respectively. Carbonate in tooth enamel of herbivorous mammals is significantly and regularly enriched in 13. compared to source carbon. As a result, we can reconstruct distributions of C3.and C4 plants in geological history based on carbon isotopes of mammalian tooth enamel. Carbon isotopes of 70 mammalian tooth enamel samples from 11 Quaternary localities in northern china are analyzed. This analysis indicates that C3.plants were dominant in the terrestrial ecosystem of northern china during the Quaternary, which is completely different from Pakistan with relatively close latitudes where C4 plants were absolutely dominant. The great difference was caused by the uplift of the Tibetan Plateau. A simulation implied that a marked temperature decrease would happen in the north side of the Tibetan Plateau, but a temperature increase in the south side. The warming condition caused the transition from C3.to C4 plants in Pakistan

关键词： enamel carbon isotope northern china terrestrial ecosystem Quaternary.

Primary Study on Quantitative Reconstruction of Middle-Late Eocene Climate in Jianghan Basin

在线全文

学校读者我要写书评

暂无评论

Journal of china University of Geosciences 2002年第3期13卷 252-259页

作者： Tong Guobang Liu Zhiming Institute of Hydrogeology and Environmental Geology, chinese academy of geological sciences, Zhengding 050803.Open laboratory of Saline Lake Resources and Environment, chinese academy of geological sciences,{3. Zheng Mianping Institute of Mineral Resources, chinese academy of geological sciences,{3. Research & Development Center of Saline Lake and Epithermal Deposit, chinese academy of geological sciences,{3. Wang Weiming Nanjing Institute of Geology and Palaeontology, chinese academy of sciences, Nanjing 210008 Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological Sciences Zhengding 050803 Open laboratory of Saline Lake Resources and Environment Chinese Academy of Geological Sciences Beijing 100037 Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing 100037 Research & Development Center of Saline Lake and Epithermal Deposit Chinese Academy of Geological Sciences Beijing 100037 Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008

This paper reports our primary effort in the quantitative reconstruction ofpaleoclimate based on the thrine in phytoecology of the affinity parent plants in the stratigraphicpollen records. The Eocene pollen data come from our former study on the Mingjia borehole 1 in theJianghan basin. The fluctuating trend in the parameter curve of climate shows that the climate inthe Middle Eocene in the Jianghan basin was more or less comparable with that of the present22°―26°N, characteristic of a humid, semi-humid central-southern subtropical climate. The annualtemperature at that time dropped by 1 ℃― 4 ℃ in the Late Eocene, approximately equal to that ofthe present 23.―28°N of northern-central subtropical climate. However, the climate composite atthat time, characterized by higher temperature, small annual range and big fluctuation inprecipitation, was quite different from the present one. The average temperature in January in theMiddle Eocene, higher than that of today, ranged between 5 ℃ and 9 ℃, indicating that no effect ofwinter monsoon occurred in the Middle Eocene, though such an effect may have occurred occasionallyin the Late Eocene. Major temperature decline is recognized at the depth of 2 100 m in the borehole,as was indicated by the decline in average January temperature, the increase in annual range, andthe increase in the deciduous broad-leaved types of trees in the spore-pollen assemblage. The sharpfluctuation in the annual precipitation, usually raging from 3.0 to 1 700 mm, was favorable for themigration and accumulation of salty deposit. When the precipitation was lower than 1 000 mm,ephemera shrub increased at the same depth as that of the salty deposit. It is, therefore, deducedthat the formation of the salty deposit was attributed mainly to the dry and hot environment in thehigh mountains and deep basins. The small annual precipitation and the intense fluctuation arefavorable for the sustainable accumulation of the salts, which is different from the present

关键词： quantitative reconstruction of paleoclimate annual range function ofthrine in phytoecology fuzzy mathematics eocene jianghan basin

THE FIRST DISCOVERY OF BOLOSAURS FROM UPPER PERMIAN OF china

在线全文

学校读者我要写书评

暂无评论

古脊椎动物学报(中英文） 1995年第1期 22-23页

作者： Li Jinling (Institule of Vertebrate Paleontology and Paleoanthropology, the chinese academy of sciences {3. 100044)Cheng Zhengwu(Institutc Gcology, chinese academy of geological Sciencct beijing 100037)

The fossils forming the subject of the present study were collected from Dashankou, a Late Permian locality near Yumen, Gansu, which was first found by thelast author in early 1980’s. A trial excavation at this site proved that there exists a fossil-bearing lens containing some articulated skeletons on lower tetrapods and a huge number of isolated bones. Then, a project "Study of the Late Permian vertebrate fauna in Qilianshan and its paleobiogeography" was proposed and supported by the National sciences Foundation in *** the field seasons of 1991 and 1992 numerous amphibian and reptile remainsincluding temnospondyls, dinocephalians, eotitanosuchians and bolosaurs were collected. The Yumen assemble is comparable to those of Zone II of Russia and Tapinoccphalus zone of South Africa. A thorough preparation is still in progress and the following deals With bolosaur among the fauna. The stratum of the locality and detailed descriptions of the fauna will be given to appear seperately.

关键词： Yumen Gansu Upper Permian Bolosauridae

The upper mantle structure of the Tibetan Plateau and its implication for the continent-continent collision

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth sciences 2005年第8期48卷 1158-1164页

作者： WU Qingju1, ZENG Rongsheng1 & ZHAO Wenjin2 1. Institute of Geophysics, china Earthquake Administration, beijing 100081, china 2. Institute of Geology, china academy of geological sciences, beijing 100037, china 1. Institute of Geophysics China Earthquake Administration 100081 Beijing China 2. Institute of Geology China Academy of Geological Sciences 100037 Beijing China

The upper mantle structures of Himalayas-Tibet have been obtained from the mi-gration of receiver functions of the teleseismic events recorded by INDEPTH-III. The result of migration imaging shows a dipping interface subducting northward from the depth of 100 km to the 410-km discontinuity underneath southern Tibet. It indicates that the lithospheric mantle of the Indian continent had been detached from the crust and deeply subducted to the upper mantle of Eurasia during the Indo-Eurasian collision. This kind of continent-continent collision process is fundamentally different from the oceanic collision.

关键词： Tibetan Plateau, receiver function, upper mantle structures, Indo-Eurasian collision, dipping interface.