• 1994年第68卷第4期文章目次
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    • Structural Styles of the Longmenshan Thrust Belt and Evolution of the Foreland Basin in Western Sichuan Province, China

      1994, 68(4).

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      摘要:The Longmenshan thrust system consists of two major groups of structural styles according to the depth of their involvement: basement thrusts-compressional fault blocks; fold-thrust system in the cover. In cross-section, the Longmenshan structural belt is divided into 5 zones. The propagation of the Longmenshan thrust system is piggy-back due to pushing at the early stage and overstep due to gravity sliding at the late stage. Balanced cross-sections and palinspastic reconstruction reveal that the total sliding displacement of the thrust system amounts to 120 km. The tectonic evolution of the Tethys domain in western Sichuan has experienced 5 stages: continental break-up; ocean-continent subduction ; continent-arc collision; orogenic thrusting; uplift of western Sichuan.

    • Two Types of Archaean Grey Gneiss in North China and Their Geological Significance

      1994, 68(4).

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      摘要:Grey gneisses are tonalitic intrusive rocks that have Archaean characteristics and tectonic significance. Archaean grey gneisses in North China may be classified into two types: the Zunhua type and the Heagshan type. Grey gneisses of the Zunhua type alternate with basic granulites, forming a bimodal migmatitic suite. The rock is characterized by complex mineral composition, highly varied REE patterns and positive Eu anomaly and originated from autochthonous or partly autochthonous deep-level migmatization with a high degree (30%±) of fusion. As the sub-stratum in the root of the early-stage high-grade greenstone belt, they prevented basic rocks from sinking. Grey gneisses of the Hengshan type are characterized by a relatively distinct intrusion form, large-amplitude upward emplacement, rather simple mineral composition, only slight/changes of REE patterns and absence of Eu anomaly. The rock is a product of subduction and underthrusting of the high-grade greenstone belt and then fusion and emplacement w

    • The infrastructure and Origin of Upper Sinian Cherts on the Southeast Continental Margin of the Yangtze Platform

      1994, 68(4).

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      摘要:Through microscopic and SEM observations and X-ray diffraction and energy spectrum analyses, the oldest sponge spicules and radiolarians have been found in bedded cherts and it is proposed that microbial activity of algae and bacteria played an important role in silica precipitation. The microbial activity resulted in the formation of a series of single crystals and crystal aggregates with peculiar shapes. Biogenic single crystals usually occur in spherical, rod, platy, colloidal and granular forms. The most common aggregates are framboidal aggregates composed of dense spherical quartz crystals, which are considered to be of typical bacterial origin. Other aggregates, such as favositic, double-spherical, chain-spherica'l and coccoid ones, are considered to be probably the result of silicification of algal cells and mainly of primary sedimentary origin. This paper also discusses the ultrastructural features and diagnostic indications of jasper rocks formed in a submarine hydrothermal environment and cher

    • A Genetic Model for Ore Magma of the Chibaisong Copper-Nickel Sulphide Deposit, Jilin

      1994, 68(4).

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      摘要:In the early 1980's, the author proposed his view that copper-nickel sulphide deposts are of ore magma origin. For more than ten years, this view has aroused attention of his colleagues at home and abroad. In this paper an attempt is made to deal with the genetic model for ore magma of copper-nickel sulphide deposits in more details on the basis of geological, geochemical, petrophysico - chemical and thermodynamic studies of the Chibaisong copper-nickel sulphide deposit in the Changbai Mountains, Jilin province.

    • Isotopic Ages of the Penglai Group in the Jiaobei Belt and Their Geotectonic Implications

      1994, 68(4).

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      摘要:The Penglai Group in the Jiaobei Belt is the only remaining cover of the Archaean to Early Proterozoic crystalline basement in eastern Shandong. The ages of deposition of the Penglai Group and of its deformation and metamorphism have long been a subject of speculation. Whole-rock Rb-Sr ages, illite-whole-rock pair Rb-Sr ages and illite K-Ar ages recently obtained from the Penglai Group slates are reported and interpreted in this paper. On the basis of structural and metamorphic studies coupled with analyses of illite crystallinity, XRD and SEM , a whole-rock age of 473±32 Ma (Ordovician) is interpreted as the time of termination of burial metamorphism experienced by the Penglai Group. Therefore, the age of the Penghai Group is older than Ordovician. The first-phase folding and syntectonic low greenschist facies metamorphism in the Penglai Group, i.e. the Penglai Movement, took place before 299±4 Ma B.P., i.e in the Late Carboniferous. The Penglai Movement that occurred in the Jiaobei Belt on the south

    • Cambrian- Ordovician Deep - Water Deposits in Southwest Jiangxi, China

      1994, 68(4).

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      摘要:The Cambrian-Ordovician rocks in southwestern Jiangxi are mainly composed of deep-water deposits, in which 5 facies have been recognized: sandstone facies, sandstone-mudstone facies, siltstone-mudstone facies, mudstone (slate)facies, and chert facies. They are of turbidity current origin and are related to pelagic and hemipelagic deposits. In the light of facies distribution, the Cambrian-Ordovician deposits can be classified into 3 facies associations formed in middle fan, outer fan and deep-sea plain environments respectively. The 3 different orders of vertical cycles in the stratigraphic sequence are considered to be controlled by factors such as sea-level fluctuation, basin subsidence and submarine fan progradation. The tectonic setting of the sedimentary basin is interpreted as passive continental margin based on the chemical composition analysis of the sandstone.

    • The System Analysis and Reliability Evaluation of Rock Slopes

      1994, 68(4).

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      摘要:The principal of preferred plane analysis is a new research view and model of rock slope engineering geology. It advocates that the rock slope stability, boundary conditions and failure model are controlled by preferred planes. Therefore, the problem of slope stability evaluation can be converted into the search for preferred planes and determination of preferred separating bodies. The organic combination of the deterministic model and the indeterministic model can be realized by applying the systems engineering principle and the research model and method of reliability analysis in the quantitative evaluation and prediction of rock slope stability. Finally, the paper presents the case studies of slopes of the Yangtze Gorge Project and the Ma'anshan openpit mine.

    • ACTA GEOLOGICA SINIC AContents of Vol. 7, 1993

      1994, 68(4).

      摘要 (1225) HTML (0) PDF 0.00 Byte (70) 评论 (0) 收藏

      摘要:NO.lSeismie Aetivity and Fuzzy ComPrehensive Evaluation of Crustal Stability in the Beijing Region····························································……Huang Qinghua嘴庆华、 Ma Yinshens吗寅生、and sons Xinehu味新初)Arohaean Greenstone Beits in china······……,’’··················……Shen Baofen枕保丰X Peng xiaoliang澎晓亮入Luo Hui酪辉)and Mao Debao凭德宝)The M echanism of Bacterial Oxidat…

    • NOTES FOR CONTRIBUTORS

      1994, 68(4).

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      摘要:1. All contributions should be submitted in English. Titles of references other than English, French, German, Spanish and Russian should be translated into English, with the specific original language duly indicated. 2. Only unpublished original papers, not simultaneously submitted or published olsowhere, will be accepted, and copyright in published papers will be vested in the Publisher.

主编 :侯增谦

主管单位 :中国科学技术协会

主办单位 :中国地质学会

创刊 :1922年

国际标准刊号 :ISSN 1000-9515

国内统一刊号 :CN 11-2001/P

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