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

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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, {3. Academy of geological Sciences, beijing beijing U niversity of Science and Engineering, beijing fei zhenbi 1 institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing2 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

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

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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, {3. Academy of geological Sciences, beijing fei zhenbi China University of Geosciences Beijing China University of Geosciences Wuhan Hubei institute of geomechanics Chinese Academy of Geological Sciences Beijing [?]Cheng Jie Born in July 1963 graduated from the Specialty of Exploration East China College of Geology in 1984 received a master degree at China University of Geosciences in 1987. He is now associate professor of China University of Geoscience (beijing) and engages in the teaching and study of vertebrate palaeontology and Quaternary Geology.

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

Microstructures of Coal and Their Relation with Gas Outhursts——A Case Study of the Yutianbao Coal Mine, Nantong, Sichuan

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Acta Geologica Sinica(English Edition) 1992年第4期66卷 385-396,443-444页

作者： li Kang Zhong Dalai institute of Geology, Academia Sinica, beijing fei zhenbi

Outbursts of coal and gas are closely related to coal microstructures. Part of microstructures of coal areassociated with the coal-forming environments, but most of them are produced by tectonic deformation. In thispaper the types of microstructures of coal are distinguished according to the types and features of tectonicdeformations, which is convenient and can be easily employed by geologists. Based on the SEM study on coalpetrography of No.4 and No.6 coal seams of the Yutianbao coal mine, Nantong coal field, five types of coalare distinguished: nontectonic coal, microfissure coal, microcleavage coal, cataclastic coal and mylonitic *** microstructural features of various types are described in detail and their geological implications and rela-tionships with coal and gas outbursts are also discussed. Special mention is made of a series of the features ofplastic deformation of mylonitic coal. It is concluded that, other things being equal, the place with myloniticcoal is the most likely risk site for *** process and mechanism of coal and gas outbursts are suggested based on a series of changes inmicrostructures of the coal after bursting. In the process of gas outbursts, the plastic deformation issuperimposed by brittle deformation, thus ejecting large quantities of coal dust.

关键词： coal microstructures gas outbursts