检索结果-南通市图书馆

The Evolution of Alpine Ultramafic Rocks and Partial Melting of the Upper Mantle

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1993年第1期67卷 43-61,122页

作者： Bao Peisheng, Wang Xibin, Hao Ziguo and Peng Genyong institute of geology, chinese academy of geological sciences, beijing fei Zhenbi institute of geology Chinese Academy of Geological Sciences Beijing

Ultramafic rocks of Tibet and Xinjiang are the products of partial melting of the upper mantle. The evolution of their mineral composition is marked by two parallel evolutionary series: one is the progressive increase of the 100 Mg/(Mg+Fe^(2+) ratio of silicate minerals in order of lherzolite→harzburgite→dunite, i.e. the increase in magnesium; the other is the increase of the 100 Cr/(Cr+Al) ratio of accessory chrome spinel in the same order, i. e. the increase in Chromium. The above-mentioned evolutionary trends are contrary to that of magmatic differentiation. The evolution of fabrics of ultramafic rocks is characterized by progressive variation in order of protogranular texture→melted residual texture, symplectic texture and clastophyritic texture→equigranular mosaic texture and tabular mosaic texture. Experiments of partial melting of lherzolite have convincingly shown that the evolution of Alpine ultramafic rocks resulted from the partial melting of pyrolite. Various subtypes of them represent different degrees of partial melting. The vertical zoning marked by more basic rocks in the upper part and more acid rocks in the lower actually belongs to the fusion zoning of pyrolite.

关键词： Alpine ultramafic rocks upper mantle partial melting

New Data of Daomanite and Hongshiite

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2001年第4期75卷 458-465页

作者： YU Zuxiang institute of geology, chinese academy of geological sciences, beijing 100037 fei Zhenbi

In 1974 the author preliminarily reported two new platinum group minerals—daomanite and hongshiite. The two minerals were accepted by the Commission on New Minerals and Minerals Names of the International Mineralogical Association in 1976 and 1982 respectively. Because of the conditions at that time, the work was preliminary, for example, there were only reflectance values of four wave bands. Recently the author again made measurements of reflectances, corrected cell parameters by the four-circle diffractometer and electron diffraction and supplemented their new occurrences and nomenclature.

关键词： daomanite hongshiite new data

Himalayan Tectonic Evolution in the East Asian Peri-Pacific Region

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1990年第3期64卷 233-246页

作者： Cui Shengqin Li Jinrong institute of Geomechanics, chinese academy of geological Scinences, beijing fei Zhenbi institute of Geornechanics Chinese Academy of Geological Scinences Beijing

This paper summarizes the Late Palaeozoic. Indosinian and Yanshanian palaeotectonic settings in theperi-Pacific region of East Asia. On that basis, the Himalayan crustal movement in the region is divided intothe early and late tectonic stages and two principal tectonic phases. From the ocean to the continent, 5 giganticHimalayan formation-deformation belts are distinguished; they are the Northwest Pacific trench-island arcbelt. the Northwest Pacific marginal sea basin bell. the East China Sea-northern South China Seacontinental-shelf down-faulted belt. the East Asian epicontinental rift belt. and the East Asian intracontinentalrift belt. The Early and Late Himalayan tectonic evolution is dealt with. Finally the state of the Himalayan re-gional stress field and its evoution in the region are discussed. It is considered that the mechanism of their for-mation is closely related to the continent-ocean and surface-deep earth interaction.

关键词： Asia

Mineralogy and Mode of Occurrence of Gold, Silver and Bismuth of the Caijiaying Lead-Zine-Silver Deposit, Hebei 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4期65卷 371-385,461页

作者： Huang Dianhao Ding Xiaoshi Wu Chengyu Zhang Changjiang institute of Mineral Deposits, chinese academy of geological sciences, beijing geological Party No.3, Hebei Bureau of geology and Mineral Resources, Zhang jiakou, Hebei fei Zhenbi institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing China

The deposit under study is a hydrothermal filling-metasomatic vein type lead-zinc-silver deposit, in whichgold and silver can be recovered as by-products. These metals mainly occur as microgranular native gold,electrum, stephanite, acanthite, pyraragyrite, freibergite, and native silver. Gold minerals tend to be associatedwith galenobismutite, native bismuth and unnamed Bi_2Te. They are either enclosed in pyrite, marmatite,iron-bearing sphalerite and galens or fill the microfissures of these minerals. Silver minerals usually occur incleavages or fissures of galena, marmatite and pyrite, but are not associated with gold and bismuth minerals.Gold and silver mineralizations occurred later than lead and zinc, while the silver mineralization was precededby that of gold.

关键词： Mineralogy and Mode of Occurrence of Gold Hebei Province

Permian Alkaline Granites in Central Inner Mongolia and Their Geodynamic Significance

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1995年第1期69卷 27-39页

作者： Hong Dawei, Huang Huaizeng, Lithosphere Research Center, chinese academy of geological sciences, beijingXiao Yijun, institute of geology, chinese academy of geological sciences, beijingXu Haiming,institute of Mineral Deposits, chinese academy of geological sciences, beijingand Jin M anyuanTianjin geological academy, Ministry of Metallurgical Industry, Tianjin fei Zhenbi Lithosphere Research Center Chinese Academy of Geological Sciences Beijing China

Alkaline granites (Rb-Sr ages 276-286 Ma)occurring in the Bayan Ul-East Ujimqin belt at the southern margin of the Siberian plate originated in a tensional tectonic environment about 60 Ma earlier than the Late Devonian to Early Carboniferous collision between the Siberian and Sino-Korean plates. They belong to post-orogenic A-type granites and may be used as an indicator of the end of the orogeny. At the northern margin of the Sino-Korean plate, however, only late-orogenic calc-alkaline granites occurred during the late Caboniferous-Permian, and alkaline syenites did not appear until the Late Triassic. The asymmetric magmatism at the margins of the two neighbouring plates might be controlled by the differences in size and mass of the two plates.

关键词： alkaline granite geodynamics Inner M ongolla

The Igneous Rock Series and Tin Polymetailic Minerogenetic Series in the Tengchong Area, Yunnan

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1989年第2期63卷 175-187页

作者： Mao Jingwen institute of Mineral Deposits, chinese academy of geological sciences, beijing fei Zhenbi

This paper discusses the late Yanshanian-Himalayan igneous rock series and minerogenetic series (Cheng et al., 1979, 1982) related to tin polymetallic deposits in the Tengchong area. The multi-stage differentiation and evolution of the igneous rock series led to the concentration of metal and ore-forming elements in a cupola of a granite body formed in the late stage. The minerogenetic series shows a zoning of Nb-Ta-W-Sn, Sn-Fe and Sn around the cupola in space and a multi-stage regularity in time. Finally a minerogenetic model and three key factors of tin minerogenesis are put forward for tin polymetallic deposits in the area.

关键词： The Igneous Rock Series and Tin Polymetailic Minerogenetic Series in the Tengchong Area Yunnan

The Existence of the Negative Charge of Gold in Sulphide Minerals and Its Formation Mechanism

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1995年第3期69卷 303-315,341页

作者： Li Jiuling, Feng Daming, Qi Feng and Zhang Guilan institute of Mineral Deposits, chinese academy of geological sciences, beijing beijing U niversity of Science and Engineering, beijing fei Zhenbi institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing beijing University of Science and Engineering Beijing

Through a study, particularly an X-ray photoelectron spectroscopy (XPS or ESCA) analysis, of gold-bearing arsenopyrite and pyrite in Carlin-type gold deposits of Guangxi, China, and hydrothermally synthesized gold-bearing pyrite and marcasite, the authors have found that these minerals contain 'invisible gold' whose binding energy is lower than that of native gold (Au°). Therefore they suggest that gold occurs in a negative charge state in these sulphide minerals as it replaces some sulphur and is combined with sulphur with the covalent bond. This paper also preliminarily discusses the possibility of its formation from the chemistry and geochemistry of gold, crystal chemistry of arsenopyrite, pyrite and marcasite and geochemical environment.

关键词： Carlin-type gold deposit sulphide invisible gold chemical bound gold negative charge of gold

A Study of the Rhenium-Osmium Geochronometry of Molybdenites

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1995年第2期69卷 171-181页

作者： Du Andao, He Hongliao, Yin Ningwan, Zou Xiaoqiu,Sun Yali, Sun Dezhong, Chen Shaozhen and Qu Wenjun institute of Rock and Mineral Analysis, chinese academy of geological sciences, beijing fei Zhenbi institute of Rock and Mineral Analysis Chinese Academy of Geological Sciences Beijing

This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decomposition of samples by means of alkali fusion, extraction of rhenium by acetone and extraction of osmium by distillation. The recovery of both elements in the entire process was more than 90% . The blanks of analyses were 0.07 ng for rhenium and 0.01 ng for 187Os. The mineralization ages of molybdenites from four molybdenum deposits in China were determined by using this method, with a precision (2σ)of about ±3% . These results agree satisfactorily with their geological backgrounds. The Re-Os method can directly determine ages of metal deposits and reflect the true ages more reliably than other dating methods that only determine the ages of country rocks from which mineralization ages are inferred. As many hydrothermal sulphide deposits usually contain molybdenites, this method has bright prospects of wide application.

关键词： rhenium-osmium method molybdenite ore-forming age determination isotope dilution inductively coupled plasma source mass spectrometry

New Quaternary Mammalian Faunas and Cave Deposits in the Zhoukoudian Area,beijing

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1997年第3期71卷 231-243页

作者： Cheng Jie Tian Mingzhong Cao Boxun and Zhao Zhizhong China University Of Geosciences, beijing China University of Geosciences,Wuhan, Hubei institute of Geomechanics, chinese academy of geological sciences, beijing fei Zhenbi

From 1985 to 1987, four new localities with abundant fossil mammals were dis-covered by Cao, Tian and others in the Zhoukoudian (Choukoutien) area, beijing. They are theEast, West, Shangdian and Donglingzi caves. The East Cave fauna consists of 28 speices ofmammals and its age is middle Early Pleistocene. The East Cave assemblage shows that a tem-perature-falling event took place at around 1.20 Ma B.P. at Zhoukoudian. Sixteen species ofmammals were collected from the West Cave, which are mainly forms of late Early Pleistoceneage. The West Cave fauna represents a transitional fauna from the East Cave fauna (dry-cold)to the fauna (warm) at locality 9. The Shangdian Cave fauna is composed of four forms, beingMiddle Pleistocene in age. The Donglingzi Cave fauna contains 21 Late Pleistocene forms. Inthe cave two fossil horizons may be distinguished. The age of the lower horizon is early LatePleistocene, which is equivalent to that of the New Cave fauna; while the fauna of the upper ho-rizon may be correlated with the Upper Cave fauna.

关键词： Zhoukoudian Quaternary mammalian fauna biostratigraphy