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971.
972.
陆源碎屑岩是陆相沉积盆地的主要充填物,其成分主要受物源区母岩成分控制。通过系统分析碎屑岩成分特点可以再造沉积盆地的构造演化历史。对吐哈盆地分别采用岩矿和地球化学分析手段进行系统分析,结果显示两种分析所得结构吻合性极好,反映盆地的构造演化分为二叠纪、三叠纪-侏罗纪以及白垩纪-第三纪3个演化阶段,在各阶段地层成分出现较大差异,是盆地及相邻地区遭受构造运动改造的结果。 相似文献
973.
Geochemical Characteristics of a Veinlet Kupferschiefer Profile from the Lubin Mine, Southwestern Poland 总被引:3,自引:0,他引:3
Previous studies have shown that the ascending, oxidizing brines play a very important role in Kupferschiefer mineralization. Fractures could be the pathway of the brines. In order to clarify the influences of the brines on bulk organic matter, aromatic hydrocarbons and Kupferschiefer mineralization, one veinlet Kupferschiefer profile from the Lubin mine, southwestern Poland was studied with the microscopic, geochemical and Rock-Eval methods. The microscopic results indicate that organic matter of the veinlet sample consists dominantly of bitumen. Its extract content is higher than in other samples. The dominant aromatic compounds are naphthalene and alkylated naphthalenes (Na-PAH), which have migrated into the veinlet sample from other sediments. The content of phenanthrene and its methylated derivatives (Ph-PAH) is much lower than in other samples. The reason may be due to their heavier mass than Na-PAH. It is more difficult for Ph-PAH to migrate. The Na-PAH was probably removed from the shale by dist 相似文献
974.
CHEN Bailin LI Zhongjian DONG Faxian Institute of Geomechanics Chinese Academy of Geological Sciences Beijing 《《地质学报》英文版》2001,75(1):94-100
The Qifengcha-Detiangou gold deposit is a medium-sized deposit recently found in Huairou County, Beijing. It belongs to the altered mylonite type with superimposed quartz vein type and is related to the early Yanshanian magmatic activity. Characterized by multiperiodic activity, the NE-trending Qifengcha fault is a regional ore-controlling structure in the area, and gold mineralization develops only in its southeastern part. Meanwhile, gold mineralization is controlled by the Yunmengshan metamorphic core complex. The nearly N-S- and E-W-trending low-angle detachment faults, reformed by the Qifengcha fault in the northwestern part of the core complex, are the main ore-bearing faults. All discovered gold deposits are located within an area 1.5-4.0 km away from the boundary of the upwelling centre. The N-S- (NNE-) and E-W-trending ore-bearing faults are ductile-brittle structural zones developing in shallow positions and subjected mainly to compressive deformation. The structural ore-controlling effects ar 相似文献
975.
DENG Jun FANG Yun YANG Liqiang YANG Junchen SUN Zhongshi WANG Jianping DING Shijiang WANG QingfeiChina University of Geosciences Beijing China University of Geosciences Wuhan Institute of Geology Geophysics Chinese Academy of Sciences Beijing Jilin University Changchun 《《地质学报》英文版》2001,75(2):220-232
Based on an analysis of the fractal structures and mass transport mechanism of typical shear-fluid-ore formation system, the fractal dispersion theory of the fluid system was used in the dynamic study of the ore formation system. The model of point-source diffusive illuviation of the shear-fluid-ore formation system was constructed, and the numerical simulation of dynamics of the ore formation system was finished. The result shows that: (1) The metallogenic system have nested fractal structure. Different fractal dimension values in different systems show unbalance and inhomogeneity of ore-forming processes in the geohistory. It is an important parameter to symbolize the process of remobilization and accumulation of ore-forming materials. Also it can indicate the dynamics of the metallogenic system quantitatively to some extent. (2) In essence, the fractal dispersive ore-forming dynamics is a combination of multi-processes dominated by fluid dynamics and supplemented by molecule dispersion in fluids and 相似文献
976.
Characteristics of Karst Ecosystems of Vietnam and Their Vulnerability to Human Impact 总被引:10,自引:0,他引:10
Do TUYET 《《地质学报》英文版》2001,75(3):325-329
Karst in Vietnam covers an area of about 60,000 km2, i.e. 18 % of the surface of the country. The country has an annual average temperature of 24@, an annual average rainfall of 2300 mm and a relative humidity of about 90%. Karst in Vietnam is typified by peak cluster-depression landscapes ranging in elevation from 200 to over 2000 m. Tower and coastal karst landscapes also exit. Because of naturally favourable conditions, karst ecosystems are diverse and very rich. Higher plants (cormophytes) are abundant. They are represented by approximately 2000 species, 908 genera, 224 families, 86 orders and 7 phyla. They form a thick vegetation cover of evergreen tropical rainforest. Knowledge about lower plants is limited. The fauna is rich and diverse. Phyla such as Protozoa, Vermes, Mollusca and Arthropoda are yet ill known. Preliminary results show that the phylum Chordata is represented by 541 species from 80 families, 40 orders and 5 classes. There exist many precious and rare mammals, in particular some en 相似文献
977.
本文以塔里木盆地为例,通过流体势分析,油田水化学分析,包裹体测温和原油中含氮化合物的丰度及比值研究,确定塔中地区晚海西期油气主要来自东北和西北两个方向,在中段形成塔中4油藏,并通过流体运移方向分析,认为塔中4油藏在喜马拉雅期受淡水冲洗破坏,使油所储量大大减少,轮南地区的油气主要来自南部的满加尔凹陷和两侧的哈拉哈塘凹陷和草湖凹陷,其中草湖凹陷两次供油气,而其他两个凹陷三次供油气,流体运移方向的研究有助于认识油气的分布规律,对确定勘探的有利区带和目标具有重要意义。 相似文献
978.
在前寒武纪变质基底和造山带中,由于多期热-构造事件的影响,以及透入性片理和构造岩的发育,造成变质深成侵入体,构造岩和表壳岩鉴别的困难,。即使表壳岩系统也因强烈的变形而不能够完全运用叠置地层学的方法进行地层划分和对比,因而事件地质学的思路和方法的应用颇为广泛。地质事件是地史演化过程中,不同于正常地质历史发展的突发性,或灾变性,或具有特殊意义的地质记录,在正确识别地质事件的性质和特征的基础上,需建立地质事件的序列,事件序列的建立包括两个步骤,首先要在野外翔实的工作基础上建立地质事件的相对序列,然后在此基础上运用多元同位素测年方法标定主要或特征地质事件的时代,建立地质事件的年代格架。地质事件群或组合则是成因上有联系,空间上相匹配,时间上有先后的一组地质事件,它比单独的一个事件更深刻地反映地质历史演化的过程和特点,正确归并和界定地质事件群在研究区域地质演化特征或进行大区域间的地质对比时具有十分重要意义。 相似文献
979.
980.
GONG Yiming Faculty of Earth Science China University of Geosciences Wuhan LI Baohua Laboratory of Marine Geology Tongji University Shanghai WU Yi Guangxi Institute of Geology Nanning 《《地质学报》英文版》2001,75(4):354-363
Four hierarchical cyclothems, superbundlesets, bundlesets, bundles and laminae, have been identified from the Devonian Frasnian-Famennian carbonate strata in Guangxi, South China. Their hierarchical structures, ratio relationships and sequence in conodont zones are continuous and stable and can be traced across different facies zones and sedimentary basins. Our data show that hierarchically organized superbundlesets, bundlesets, bundles and laminae correspond to the long eccentricity, eccentricity, obliquity or precession and sub-Milankovitch cycles respectively. Their periods were 400,000, 100,000, 33,333, 16,667 and 8,000-17,000 a, respectively. The ratios of long eccentricity to eccentricity, eccentricity to obliquity, and eccentricity to precession in the Devonian are 1:4, 1:3 and 1:6 respectively. Using these hierarchical Milankovitch cyclothems, chronostratigraphical division and correlation can be realized at a resolution of 100 ka or 10 ka at the Frasnian-Famennian transition. The time intervals 相似文献