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1.
Study of the Emplacement Mechanism of the Fenghuangshan Granite Pluton and Related Cu-Au Mineralization in Tongling, Anhui Province 总被引：4，自引：2，他引：2
WU Ganguo ZHANG D LI Dongxu ZHANG Xiangxin SHAO Yongjun ZANG Wenshuan WANG QunfengKey Laboratory of Lithospheric Tectonics Exploration China University of Geosciences 《《地质学报》英文版》2004,78(2):492-502
The Fenghuangshan Pluton is located in the Tongling polymineral-cluster district in the middle-lower section of the Yangtze metallogenic belt. In tectonic terms, it is in the middle of the Guichi-Fanchang faulted fold bundle of the lower Yangtze Platform fold belt between the Dabie Orogenic Belt and the Jiangnan Massif. Analyses of the structural deformation characteristics of both the contact zone and the interior of the pluton are used to explain its emplacement mechanism. The foliation and lineation of the pluton, consisting of the oriented distribution of dark minerals and xenoliths, mainly concentrate along the margin of the pluton. Toward the center of the pluton, the foliation structure becomes weak, showing intense compression formation at the margin, and reflecting the conformable intrusion of the pluton. The relatively gentle lineation is evidence of a rotatory emplacement mechanism. Relatively steep marginal foliation reflects compression expanding. Affected by the thermal power of the pluton, 相似文献
2.
The Late Precambrian Luoquan Formation occurring on the southern margin of the North China platform is of important significance for the study of the tectonics, palaeogeography, palaeoclimatology and regional stratigraphy of the North China and Yangtze platforms. The origin of diamictites of the formation has long been a subject of controversy. Recently a certain type of cross bedding structure has been recognized in the massive diamictite. Analysis of the process of deposition indicates that the structure was formed by the basal melt-out process of the glacier and, to some extent, its form is the manifestation of the primary structure of basal debris-rich glacial ice. The discovery of this sedimentary structure is inducive to the understanding and reconstruction of the features and environmental conditions for the development of the glaciers in the Luoquan Glacial Epoch. 相似文献
3.
Chen Baoren Liu Shuyun Earth Sciences Dept. Nanjing University Nanjing Jiangsu China Jin Peikang Geological Dept. Tulane University New Orleans LA U.S.A. Dong Shouyu Hebei Province Seismological Bureau Shijiazhuang Hebei China 《《地质学报》英文版》1993,67(4)
The fluctuation of most of the hydrograph in the deep aqueous system records the fluid pulsation in lithosphere and variation of the earth's crust. Many observations have verified that groundwater is an ideal information carrier of the crust. In this paper, the series of input (precipitation, air pressure, Earth tide etc.) and output (water level, artesian flow) of the deep aqueous system are studied by using the spectrum analysis and system theory. The application concepts of transfer function and the spectral structure of the hydrograph enrich the knowledge of the deep aqueous system. Two typical spectral structures of the hydrograph of the deep aqueous system are obtained by comparing with many water-bearing systems of the Jizhong depression. One is from well Ma-17 and the other is from the well Xinze-5. Finally, the physical models of forming the spectrum of the hydrograph are constructed on the basis of the spectrum research on the deep aqueous system. 相似文献
4.
We investigated the weathering-pedogenesis of carbonate rocks and its environmental effects in subtropical regions of China. The investigation demonstrated that the weathering- pedogenesis of carbonate rocks is the process of a joint action of corrosion and illuviation and metasomatism in subtropical region. It is characterized by multi-stage, multi-path and multi-style. With the persisting development of weathering-pedogenesis of carbonate rocks, metasomatic pedogenesis progressively became the main process of the weathering-pedogenesis and the dominant style of formation of minerals. And it proceeds through the whole process of evolution of the weathering-pedogenesis of carbonate rocks. The stage evolution of weathering-pedogenesis of carbonate rocks and the fractionation evolution of newly produced minerals are characterized by obvious vertically zoning structures and the rules of gradation of elements geochemical characteristics in the carbonate rocks weathering profiles. The geochemical process of weathering-pedogenesis of carbonate rocks can be divided into three geochemical evolution stages, i.e., the Ca, Mg-depletion and Si, Al-enrichment stage; the Fe, Mn enrichment stage and the Si-depletion and Al-enrichment stage in the subtropical regions. Consistent with the three geochemical evolution stages, the sequence of formation and evolution of minerals can be divided into the clay mineral stage; the Fe, Mn oxide and the gibbsite stage. The influence of weathering-pedogenesis of carbonate rocks on the chemical forms of heavy elements is mainly affected via newly produced components and minerals in the process of weathering-pedogenesis, e.g., iron oxide minerals and organic matters. The important mechanism for the mobilization, transport and pollution of F and As is affected the selective adsorption and desorption of F and As on the surface of iron oxide minerals in the subtropical karst zones, i.e., the selective adsorption and desorption on mineral surfaces of newly produced minerals in the process of weath 相似文献
5.
It has been over a hundred years since the birth of research on Chinese geosciences history, which was accompanied by the continuous progress of Chinese geosciences. For hundreds of years, it has grown out of nothing to brilliant performance by several generations of Chinese geologists committing their hearts and minds with the spirit of exert and strive without stop to promote the process of China's industrialization and to produce the significant impact on serving the society. The study of Chinese geosciences history reflects objectively and historically the history of geosciences in China, which has recorded, analyzed and evaluated the dynamic process sitting in the background and clue of the history of Chinese geosciences development. The study of the history of geological science has roughly experienced two stages in China. The first stage is the study of individual researchers. It spanned approximately 70 years from the early 20th century to the end of the 1970s. The research contents were mainly based on the evolution of geological organizations, the development and utilization of individual mineral species, the history of deposit discovery and the research of geological characters. The main representatives are Zhang Hongzhao, Ding Wenjiang, Weng Wenhao and Li Siguang, Ye Liangfu, Huang Jiqing, Yang Zhongjian, Xie Jiarong, Gao Zhenxi, Wang Bingzhang and etc. The most prominent feature of this period is the accumulation of a very valuable document for the study of the history of China's geological history and lays a foundation for the exchange of geological science between China and foreign countries. The second stage is organized group study. It took around 60 years from the 1920s to 1980s. It includes the history of Chinese geology, the history of geological organizations, the history of geological disciplines, the history of geological education, the history of geological philosophy, the history of Chinese and foreign geological science communication, the history of geologists and etc. The most chief feature of this stage is the birth of academic research institute―the establishment of the Commission on the History of Geology of the Geological Society of China. 相似文献
6.
Relationship between the Malan Loess and the Salawusu Formation in the Salawusu River Area,Ordos,and Their Geological Ages 总被引：3，自引：0，他引：3
In the middle and lower reaches of the Salawusu River. the Salawusu Formation regarded traditionallyas fluvio-lacustrine deposits actually includes a series of strata which mainly consist of eolian sandy depositsnamed as "Chengchuan Formation" by the authors. The eolian sand of the Chengchuan Formation and theMalan loess distributed in the upper reaches of the Salawusu River are deposits of sand and loess faciesformed by wind action during the same period. The relationship of the Chengchuan Formation and theMalan Loess with the Salawusu Formation which is really of fluvio-lacustrine deposits is that the formertwo superpose the latter. This can be demonstrated by the difference of the extinct species proportion of thefaunas in different strata. In this area. the Salawusu formed during the early period of Late Pleistocene.while the Malan Loess and the Chengchuan Formation deposited during the late period of the LatePleistocene. 相似文献
7.
KOU Linlin DONG Xiaopeng LI Zhenhong CUI Jiawei MA Zhaoying LI Hailong 《《地质学报》英文版》2022,96(6):1917-1931
Daluo Mountains lie at front of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau, and are the landform boundary zone between the active Tibetan Plateau and the stable North China Craton. Studying of the late Cenozoic uplift evolution of Daluo Mountains is important for understanding the expansion mechanism of the northeastern margin of the Tibetan Plateau and its influence on the western North China Craton. In this study, the late Cenozoic uplift of Daluo Mountains is constructed from the development of the late Cenozoic alluvial fan around Daluo Mountains. The entire sedimentary sequence and framework of the fan was revealed by the newly obtained drilling core data. The cosmogenic nuclide, optically stimulated luminescence, and detrital zircon U-Pb dating results provide new evidences for discussion about the initial timing of the late Cenozoic uplift of Daluo Mountains and the key stages of uplift during the Pleistocene. The late Cenozoic alluvial fan at front of Daluo Mountains overlies a set of fluvial-facies strata; therefore, development of the alluvial-fan marks the start of late Cenozoic uplift of Daluo Mountains. The timing of this event can be constrained to ~4.64 Ma. Two extensive gravel layers (dated to ca. 0.76–0.6 Ma and ~0.05 Ma) developed during the Pleistocene, indicating two episodes of considerable uplift. This study provides a new time scale for the uplift and expansion of the arcuate tectonic belt at the northeastern margin of the Tibetan Plateau. 相似文献
8.
Tao Weiping 《《地质学报》英文版》1988,62(4):407-421
The Chinese continent is a component part of the present Eurasian plate. The history of its geologicaldevelopment is a process of the convergence of palaeo-plates. the oceanward migration of volcanic belts andvolcanic island-arcs, and the accompanying growth of the intracontinental rifts in the later stage. So theChinese continent abounds in nonmetal resources. Based on the plate-tectonic settings in which those depos-its were formed, the nonmetallic deposits can be generally classified into those related to the sutures andophiolites. those related to the volcanic island-arcs. those related to the back-arc epicontinental sea. those re-lated to the intracontinental rifts and those within the plate interior. They all show certain characteristicregularities of distribution. The evolutionary process of the Chinese continent is so complicated that somenonmetallic deposits have various origins and are characterized by multi-stage mineralization. multiplicityof types and superimposition of mineralization. All these are of great significance in deepening the under-standing of the formation and modes of occurrence of the nonmetallic deposits and in prospecting for min-eral resources. 相似文献
9.
TAN Jingjing HUANG Diying REN Dong 《《地质学报》英文版》2007,81(5):688-696
Three new fossil species of the genus Mesocupes of fossil cupedids,M.angustilabialis sp. nov.,M.latilabialis sp.nov.and M.collaris sp.nov.,are described from the Jiulongshan Formation of Inner Mongolia,China.These new species are the first three records of fossil Mesocupes in China as well as the oldest ones in the world now.This finding also extends the geographical distribution of this genus from Central to East Asia.In addition,based on the ratio of the length of the last to the penultimate abdominal ventrites of new beetles distinctly lower than that of the species from the Karabastau Formation,the age of Daohugou fossil-bearing beds might be older than that of Karatau assemblage and consequently of Middle Jurassic. 相似文献
10.
The distribution of frozen soil in our country is very broad, and the area of permafrost alone accounts for 22. 4% of the total land area. As a special kind of soil, frozen soil has many properties that thawing soil does not have due to the influence of ice cement in the soil. Among the many properties of frozen soil, the deformation and strength of frozen soil are the basic problems affecting engineering construction in frozen soil areas. The spherical template indenter test is widely used in the test of the mechanical properties of frozen soil because of its simple test process and relatively accurate test results. Compared with the conventional triaxial test or direct shear test, the test process of the spherical template indenter test is simple and easy to implement, the test period is short, and the sample preparation requirements are low. The advantage of effective cohesion is more significant. Therefore, based on the spherical template indenter test of the frozen soil, this paper estimates the strength and mechanical index of the soil through the indentation depth of the spherical template indenter test, and establishes the relationship between the force of the sample and the indentation depth of the indenter test. The specific test method is as follows:take the water-saturated frozen sandy soil made of different particle size groups(the moisture content of the sample is affected by the particle size in the saturated state)as the research object, study the variation law of the depth of the frozen soil sample pressed into the soil by the spherical indenter with time under the conditions of different fixed loads. By comparing and referring to the frozen sands of each particle size group, the long-term equivalent cohesion of the frozen sands of different particle size groups is summarized. The change law of force(long-term shear strength)with time, and the research method of elastic mechanics to solve space problems, summed up the mutual conversion between the depth St of spherical template indenters pressed into frozen sand samples under different fixed load test conditions relation. The research results show that the long-term shear strength of frozen sand based on the spherical mold test is positively correlated with its particle size. At the same time, since the ice content of frozen soil samples is proportional to its particle size, the long-term shear strength of frozen sand is also proportional to the test. The ice content of the sample increases year-on-year;the long-term shear strength of the frozen sand is related to the maximum contact pressure on the contact surface between the frozen soil and the indenter during the test, which can be expressed as Ct = γq0. The size of the relationship coefficient γ is inversely proportional to the diameter of the spherical indenter. In this paper, the spherical indenter is selected as 22 mm, and γ=3. 82×10-3. By establishing the relationship between the maximum contact pressure q0 and the long-term shear strength Ct When the maximum contact pressure q0 is the same under different fixed loads, the long-term shear strength Ct is also the same. According to this, the depth curve and the freezing depth of the frozen sand pressed into the soil by the spherical indenter over time under different fixed loads can be converted. Long-term shear strength curve of frozen sandy soil with time. It has been verified by experiments that the conversion curve of the depth of the indenter pressed into the soil with time under a fixed load of 7. 0 kg is highly consistent with the measured curve of the depth of the indenter pressed into the soil with time under a fixed load of 5. 1 kg and 7. 0 kg. © 2022 Nanjing Forestry University. All rights reserved. 相似文献
11.
V.I.STAROSTIN O.G.SOROKHTIN 《地学前缘》2004,11(1):225-235
现有的矿产资源分布资料可以说明地球历史中亲铁和亲铜元素成矿的一般规律。铁矿床在元古宙地核分离之后最为发育。除个别显著成矿高峰外 ,金的储量分布与铁类似。亲铁元素矿物的成矿潜力在古元古代也最大 ,以后逐渐降低 ,只是在显生宙 ,因地壳的再循环和古老矿床中矿石物质的活化而再次增大。元素的行为则完全不同 ,在前寒武纪时期它们的活动性为中等。亲铜矿物矿床的总量 ,在显生宙因再循环而达到最高 ,亲铜矿物矿床成矿能力较之亲铁矿物强得多 ,因为硫化物比铁金属氧化物更为活泼。地球演化的旋回性表现为超大陆形成的周期性 ,它与矿产的分布颇为一致。铁矿、亲铁元素和金成矿作用的突然激增 ,显然是在超大陆形成之后 ,并且与其早期裂解的脉动相对应。亲铜元素堆积的高峰期往往与超大陆的形成期相对应。尽管亲铜元素成矿的第三次脉动与中生代古陆 (Mesogea)的形成并不一致 ,但却与劳亚古陆及冈瓦纳古陆的裂解相一致。此种成矿堆积现象可以借助地幔内非稳态化学密度对流所诱发的地壳发展周期性来解释。根据超大陆形成的周期性推断地幔对流巨旋回的主期应为 80 0Ma ,此种周期性亦反映了具原始地幔印记的亲铁、金和亲铜元素的聚集作用过程。因此 ,地球圈层中地幔对流作用的周期性亦显著地控制了包括地幔 相似文献
12.
本文研究了位于鄂皖边境的郯-庐断裂带南段尾端地区的构造变形特征,通过野外实际工作,结合地球物理、遥感资料的分析与应用,对这条巨大平移断裂尾端的变形情况进行了初步的探讨,提出四种位移调整模式,并通过实验研究来认识平移断裂尾端的应力分布状态,以及应力与应变的相互关系。文中还就郯-庐断裂带的南延问题提出了讨论。 相似文献
13.
中国扬子海盆奥陶纪末期生物集群绝灭事件 总被引：2，自引：1，他引：2
<正> 近年来,奥陶纪末期生物集群绝灭事件的研究,越来越为人们所关注。Raup和Sepkoski(1982)认为,在晚奥陶世大约有22％科的生物绝灭,是显生宙生物集群绝灭5个最大幕之一。这次事件造成了所有海洋无脊椎动物的分异度和丰度的降低。Brenchley(1990)把晚奥陶世绝灭的若干类群的重要变化作了如下概述:阿什极尔中期的38科三叶虫,仅有14科存活到志留纪;在或接近奥陶-志留系界线,有13科腕足类绝灭,27科穿 相似文献
14.
In March and April 1972, 380 gravity stations were established in the T.F.A.I. The data were reduced to Bouguer anomalies of 5 mGal isolines. Qualitative and quantitative interpretation based on the gravity map, on seismic data and on the magnetics and physiography of the area revealed that: The crust of the Gulf of Tadjura and the central part of the T.F.A.I. is strongly oceanized and is the direct continuation of the Sheba Ridge.To the north of the Gulf, at the Dankali Mountains, the crust increases in thickness and most probably contains sialic fragments, indicating the continuation of the Danakil Chains in the T.F.A.I.To the south, the structure is bordered by a continental block, the Aysha Horst. The oceanization is concentrated only in the area of deep injections, marked by gravity maxima, whereas the rest of the area is to be described as sub-continental. The crust is attenuated from south (Aysha Horst) to north (Red Sea), from 30 to 15 km in thickness.The pattern of the gravity anomalies shows clearly liniations only along the coasts of the Gulf of Tadjura and the Straits of Bab el Mandeb. Inland the field breaks up into relative minima and maxima, indicating the fragmentation of the crust and the ‘triple junction’ nature of the area.The tectonic process is that of extension, with normal faults having maximum displacements at the northern border of the Gulf of Tadjura.The uppermost mantle has low velocity and density values due to thermal processes in the expanding zone. The state of the upper-mantle material must be that of partial melting due to high temperatures of the order of 800° to 1,000° C at about 15 km depth. 相似文献
15.
Yu.M. Scheinmann 《Tectonophysics》1973,19(1):21-37
The composition of residual matter after the segregation of the crust from the mantle is calculated. The most probable components of the mantle: garnet-peridotitic, pyrolitic and chondritic, were taken into consideration and the continental, oceanic and olivine-tholeiitic crust segregated from them. The probability of the existence of each of the proposed mantle types may be estimated as based on the obtained residual matter. It is established that the hypothesis of the pyrolitic mantle is the most acceptable.A comparison of the compositions of the continental and oceanic crust makes evident that there exist two types of differentiation processes in the upper mantle. One of them leads to the development of continents, the second of the oceanic areas. In the first case the partial melting in the mantle and the ascent of magma are accompanied by an additional evacuation of silica (?) and especially of potassium. This rise of supplementary light substance embraces the depths as great as 1000 km or more. In the case of oceanic crust such an additional rise of matter is absent since there only partial melting in the mantle takes place and accordingly the depth of the differentiation is much smaller.The differences in the process of the earth's differentiation may be easier explained if the mantle is assumed to be mobile, instead of an immobile mass. It is assumed that a differentiation of the primary matter of the planet takes place near the mantle-core boundary and that the uplift of the much lighter silicate differentiation is in the asthenosphere. On this level the mantle becomes partially melted and the resultant liquid rises into the crust. This liquid is enriched by sialic substances, particularly by potassium and may be by silica.In the regions where the rise of matter from great depth is lacking, continental crust is not formed, and oceanic crust is born.The above comparison leads in particular to the following additional conclusions: the chemical differences of the continental crust and the oceanic crust do not permit the hypotheses of continenta drift, nor of the spreading of the ocean floor and the transformation of the continental crust into oceanic. All these hypotheses become incompatible with the chemical composition of the crust. 相似文献
16.
水位涨落作用下藕塘滑坡响应特征模型试验研究 总被引：1，自引：0，他引：1
藕塘滑坡是三峡库区结构复杂的巨型古滑坡之一,由多个次级滑体和滑面组成,大坝蓄水运行以来,滑坡出现复活迹象,对周边数千人的生命财产安全构成威胁。为明确藕塘滑坡在库水位涨落作用下的响应特征、变形破坏模式和机制,以物理模型试验为手段,通过制配滑坡模型试验材料,精确控制试验中库水位涨落条件,实现了藕塘滑坡变形失稳过程试验模拟,并从试验角度探讨了藕塘滑坡响应特征和力学机制。得到以下结论:库水涨落速度越快组成滑坡的3个次级滑坡产生的变形越大,库水位下降造成的滑坡变形明显大于库水位上涨和稳定状态;库水位涨落影响主要集中于第一期次滑坡区域,当库水位快速下降时第一期次滑坡坡脚局部发生牵引式崩滑的风险大;第一期次滑坡变形造成其后的第二期和第三期次滑坡稳定性下降,随之发生变形;藕塘滑坡为动水压力型滑坡,滑坡在库水位涨落作用下发生整体沿基岩面滑移破坏的可能性不大,变形失稳模式表现为第一期次滑坡前缘的局部崩滑。试验揭示了该类滑坡在库水位涨落作用下的响应特征和变形破坏机制,可为类似滑坡的研究提供参考。 相似文献
17.
The results of the analysis of long-term radar research of the hailstorms over the central part of the Northern Caucasus are presented. Radar observations which formed the basis of experimental material were carried out continuously from the moment of the first radar echo registration until complete dissipation of the hailstorm. The computerized system of collecting, processing and the analysis of the radar information was used. Time discretization of the radar parameters of the full spatial observation averaged 3 min. Statistical sampling of radar data included 392 hail cells, for each of which the time distributions of the radar parameters both measured and calculated using the computerized system were compiled. Distribution of the hailstorms first radar echo formation zones over the observation region was compiled. Areas with the maximum frequency of the hailstorms first radar echo formation were defined. The hailstorm trajectories were analyzed. Four main types of hail cell trajectories were selected, which included 86 % of the supercells and 64 % of the long-lived multicells. The dynamic parameters of the hail core formation and development were analyzed. The hail storm characteristics of the Northern Caucasus are compared to the hail storms of Mendoza, Argentina, and Alberta, Canada. The bases of the organization of regional hail suppression services which use the rocket technology of cloud seeding are presented. The results of the cloud seeding operations during recent years are shown. 相似文献
18.
用磁性地层学方法讨论西域组的时代 总被引：9，自引：0，他引：9
通过对塔里木盆地及其周缘地区西域组砾岩的野外调查和磁性地层学研究，及相关层位的安山玄武岩同位素年龄测定等综合分析研究表明：西域组上段记录了松山负极性带下段， ２．５－１．６Ｍａ，上界大约位于奥尔都维正极性事件层位，年龄为１．６７－１．７６Ｍａ。上覆高阶地砾岩层及其下火山岩层年龄为１．４－１．６Ｍａ，西域组下段记录了高斯正极性 相似文献
19.
超覆型库岸老滑坡滑床前缘大多发育一砂卵石层,该砂卵石层的强渗透性将影响滑坡渗流场,从而影响滑坡的稳定性.以三峡库区万州中学老滑坡为例,在确定该滑坡中地下水作用模式为承压水含水层作用模式的基础上,假定砂卵石层的4种不同渗透系数,来研究在库水位波动条件下,滑床砂卵石层渗透性对滑坡稳定性的影响.分析表明,超覆型老滑坡砂卵石层的渗透系数不同,滑坡中浸润线也不同,渗透系数越小,浸润线越低,滑坡中地下水相对库水位的滞后效应越明显;库水位上升阶段、高水位运行阶段和下降初期,万州中学老滑坡各级滑坡的稳定性系数随砂卵石层渗透系数k2的增大而减小;库水位稳定在150 m时,老滑坡整体稳定性随k2的增大而增大,k2的变化对次级滑体和三级滑体的稳定性影响不明显.这对于库区老滑坡的复活和监测预警工程有较强的应用价值. 相似文献