检索结果-南通市图书馆

Crustal Motion Characteristics in the Eastern Margin of the Tibetan Plateau and Adjacent Regions after the Wenchuan Earthquake

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2015年第5期89卷 1690-1701页

作者： TANG Wenqing ZHANG Qingzhi PAN Zhongxi LI Jun YANG Cheng Chengdu institute of geology and mineral resources

The Wenchuan earthquake has altered the crustal motion characteristics in the eastern margin of the Tibetan Plateau and adjacent *** discontinuous GPS survey data for 2008–2012, the velocity field for the Eurasia reference framework has been obtained, and the general trend of contemporary crustal motion after the occurrence of the Wenchuan earthquake has been *** addition, using the velocity field, the block movement velocity has been estimated by least-squares ***, the properties and displacement rates of main faults have been obtained from the differences in velocity vectors of the blocks on both sides of the *** results reveal that there are no obvious changes in the general characteristics of crustal motion in this area after the Wenchuan *** earthquake mainly changed the rate of the movement of the Chuan-Qing block and caused variation in the movement direction of the South China *** effect of the earthquake on faults is mainly reflected in variations in fault displacement velocity; there is no fundamental change in the properties of fault *** displacement rates of the Xianshuihe fault decreased by 3–4 mm/a, the Longmenshan fault increased by 9–10 mm/a, and the northern segment of the Anninghe fault increased by approximately 9 mm/***, the displacement rates of the Minjiang, Xueshan, Huya, Longquanshan, and Xinjin faults increased by 2–3 mm/*** implies that the effects of the Wenchuan earthquake on crustal movement can mainly be observed in the Chuan-Qing, South China, and N-Chuan-Dian blocks and their internal faults, as well as the Xianshuihe and Longmenshan faults and the northern section of the Anninghe *** reason for this is that the Wenchuan earthquake disturbed the kinematic and dynamic balance in the region.

关键词： eastern margin of the Tibetan Plateau and adjacent regions GPS measurements crustal motion characteristics Wenchuan earthquake block movement fault activity

Reconstruction of the Triassic Tectonic Lithofacies Paleogeography in Qiangtang Region, Northern Qinghai-Tibet Plateau, China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2013年第2期87卷 378-394页

作者： ZHU Tongxing FENG Xintao WANG Xiaofei ZHOU Mingkui Chengdu institute of geology and mineral resources

The Triassic petrostratigraphic system and chronologic stratigraphic sketch have been updated and perfected in the Qiangtang area, Qinghai-Tibet Plateau based on the integrated 1：250000 regional geological survey and the latest research progeny. The first finished 1：3000000 Triassic tectonic lithofacies paleogeographic maps in the Qiangtang area shows that the Triassic tectonic unit in the Qiangtang area can been divided into three parts from north to south： northern Qiangtang block; Longmucuo-Shuanghu suture zone; and southern Qiangtang block. The early-middle Triassic tectonic paleogeography in the Qiangtang area is divides into three sub- units： northern Qiangtang passive continental marginal basin （NQPB）, Longmucuo- Shuanghu residual basin （LSRB） and southern Qiangtang residual basin （SQRB）. The NQPB can be subdivided into four paleogeography units： The Tanggula-Zangxiahe shallow and bathyal sea; The Wangquanhe- Yingshuiquan carbonate platform; The Rejuechaka-Jiangaidarina littoral- shallow sea; and Qiangtang central uplift. The above units of The NQPB possess EW trend, geomorphology high in the south and low in the north, the seawater depth northward. The basinal paleo-current direction is unidirectional, and basinal tectonic subsidence center is in accord with the depo-center, located in the Tanggula-Zangxiahe belt, north of the basin. The sedimentation and tectonic evolution of the NQPB are characterized with passive continental marginal basin. The Qiangtang central orogenic denuded area （ancient land） may be as a sedimentary materials source of the NQPB. SQRB can be divided into two units： Duoma carbonate platform and southern Qiangtang neritic-deep sea. The late Triassic tectonic paleogeography in the Qiangtang area is the framework of the ＂archipelagic-sea＂ as a whole, and it may be divided into three sub-units： northern Qiangtang back- arc foreland basin（NQFB）, Longmucuo-Shuanghu residual basin（LSRB） and southern Qiangtang marginal-sea basin（SQMB）. Ther

关键词： Triassic sedimentary facies tectonic paleogeography Qiangtang region Qinghai-Tibet

Chemical and Isotopic Characteristics of the Water and Suspended Particulate Materials in the Yangtze River and Their Geological and Environmental Implications

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2014年第1期88卷 276-360页

作者： DING Tiping GAO Jianfei TIAN Shihong SHI Guoyu CHEN Feng WANG Chengyu LUO Xurong HAN Dan MLR Key Laboratory of Metallogeny and mineral Assessment Institute of Mineral Resources CAGS Open Research Laboratory of isotope geology Hydrological Bureau CWRC

The chemical and isotopic characteristics of the water and suspended particulate materials（SPM） in the Yangtze River were investigated on the samples collected from 25 hydrological monitoring stations in the mainsteam and 13 hydrological monitoring stations in the major tributaries during 2003 to 2007. The water samples show a large variation in both δD（ 30‰ to 112‰） and δ18O（ 3.8‰ to 15.4‰） values. Both δD and δ18O values show a decrease from the river head to the Jinsha Jiang section and then increase downstream to the river mouth. It is found that the oxygen and hydrogen isotopic compositions of the Yangtze water are controlled by meteoric precipitation, evaporation, ice（and snow） melting and dam building. The Yangtze SPM concentrations show a large variation and are well corresponded to the spatial and temporal changes of flow speed, runoff and SPM supply, which are affected by the slope of the river bed, local precipitation rate, weathering intensity, erosion condition and anthropogenic activity. The Yangtze SPM consists of clay minerals, clastic silicate and carbonate minerals, heavy minerals, iron hydroxide and organic compounds. From the upper to lower reaches, the clay and clastic silicate components in SPM increase gradually, but the carbonate components decrease gradually, which may reflect changes of climate and weathering intensity in the drainage area. Compared to those of the upper crust rocks, the Yangtze SPM has lower contents of SiO2, CaO, K2 O and Na2 O and higher contents of TFe2 O3 and trace metals of Co, Ni, Cu, Zn, Pb and Cd. The ΣREE in the Yangtze SPM is also slightly higher than that of the upper crust. From the upper to lower reaches, the CaO and MgO contents in SPM decrease gradually, but the SiO2 content increases gradually, corresponding to the increase of clay minerals and decrease of the carbonates. The δ30SiSPM values（ 1.1‰ to 0.3‰） of the Yangtze SPM are similar to those of the average shale, but lower than those of the granite rock

关键词： Yangtze River stable isotopes water chemistry Suspended Particulate Materials(SPM) hydrology environmental implication

Aoyitake plagiogranite in western Tarim Block, NW China: Age, geochemistry, petrogenesis and its tectonic implications

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2006年第11期49卷 1121-1134页

作者： ZHANG Chuanlin1,2, YU Haifeng3, YE Haimin2, ZHAO Yu2 & ZHANG Dongsheng4 1. Key Laboratory of isotope Geochronology and Geochemistry, Guangzhou institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2. Nanjing institute of geology and mineral resources, Nanjing 210016, China 3. Tianjin institute of geology and mineral resources, Tianjin 300170, China 4. The 2nd Regional Geological Investigation Party, Xinjiang Bureau of geology and mineral resources, Changji 831100, China Key Laboratory of isotope Geochronology and Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou China Nanjing institute of geology and mineral resources Nanjing China Tianjin institute of geology and mineral resources Tianjin China The 2nd Regional Geological Investigation Party Xinjiang Bureau of Geology and Mineral Resources Changji China

SHRIMPP U-Pb zircon age and geochemical and Nd isotopic data are reported for the Aoyitake plagiogranite in western Tarim Block, NW China. The plagiogranite intruded the Middle Pro- terozoic and Lower Carboniferous with an exposure area of ca. 60 km2 and crystallized at 330.7±4.8 Ma. Rock types mainly include tonalite, trondhjemite and minor amounts of diorite and quartz-diorite. Feldspars in the rocks are dominated by oligoclase-andesine, and minor perthite observed locally. The granites are sodic with Na/K ratios (molar) between 4 and 87. Total REE (50-220 ppm) show a clear positive correlation with SiO2. There is no LRRE/HREE fractionation (LaN/YbN=0.5-1.5), me- dium negative Eu anomalies (δ Eu=0.3-0.6), high Y content and low Sr/Y ratio (~1.0). These granites exhibit relatively juvenile Nd T2DM model ages of 470 to 580 Ma and positive εNd(331 Ma) values of 6.23 to 7.65. The aforementioned characteristics are similar to those of ocean island or ocean ridge plagiogranites. However, the regional geology, especially its scale, precludes that the plagiogranite pluton was derived directly from fractionational crystallization of mantle-derived basaltic magma. We interpreted that the primary magma of the pluton might be tonalitic in composition generated by ca. 50% partial melting of the juvenile basaltic crust. The primary magma experienced intensive frac- tionational crystallization, and intruded into the middle to upper crusts to form the granite pluton. In combination with the previous regional geological data, it is concluded that the plagiogranite pluton was emplaced within the Tarim Block in respond to the Carboniferous continental rifting along the Tianshan orogenic belt.

关键词： western Tarim, Aoyitake plagiogranite, age, geochemistry, tectonic implications.

Analytical Model for the Palaeoenvironmental Evolution of the Nihewan Beds

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1期65卷 77-86页

作者： Yue Jun Wen Qizhong Tianjin institute of geology and mineral resources institute of Geochemistry, Academia Sinica Tianjin institute of geology and mineral resources China

In this paper, the evolutional characteristics of palaeoclimate and oxidation-reduction conditions as well asacidity-alkalinity environment are discussed by means of the step-regression, cluster, optimal partitioning andcorrelation analyses of CaCO_3, C / P_2O_5, Fe^(2+) / Fe^(3+), pH and Eh values, taking the Xiaodukou section in theNihewan basin as an example. The CaCO_3, C / P_2O_5 and pH were calculated respectively using the optimalpartitioning method. Thus five cold zones and six warm zones as well as five reduction and six oxidation zoneswere distinguished. Then the inductive method was used to produce four numerical groups: 8.10, 8.3-8.4,8.6-8.7 and 8.9-8,97. The above-mentioned results are respectively based on CaCO_3 content, C/P_2O_5 andpH values. From Fig. 3, Tables 1 and 2 it can be seen that the Nihewan Beds were formed mainly under a re-duction and slightly alkaline environment of cold climate, with pH values of 8.3-8.4. Fig. 3 shows that bed 35is approximately near the boundary between the Brunhes and Matuyama polarity epochs, 0.73 Ma in age; bed26 is roughly near the Jaramillo event (base), 0.97 Ma in age; bed 18 coincides roughly with themagnetostratigraphic boundary of 2.00 Ma (?). Bed 13 may be the Pleistocene-Pliocene boundary, 2.48 Ma inage. Thus geochemical zones Ⅰ, Ⅱ, Ⅲ and Ⅳ include respectively cold zones 1; 2 and 3; 4; and 5.

关键词： Analytical Model for the Palaeoenvironmental Evolution of the Nihewan Beds

Minerogenetic Model for Two Types of Fluorite Deposits in Southeastern China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1992年第1期66卷 75-88页

作者： Li Changjiang Jiang Xuliang Zhejiang institute of geology and mineral resources, Hangzhou Liu Linqun Zhejiang institute of geology and mineral resources Hangzhou

On the basis of the studies of field geology, strontium, hydrogen and oxygen isotopes and REEgeochemistry, coupled with the dating of mineralization, the authors suggest a minerogenetic model of circula-tion and drawing of Late Cretaceous geothermal waters for the fluorite deposits in southeastern China. Thismodel includes two types of mechanism: 1) the leaching-out and drawing through deep circulation of thegeothermal water, and 2) the leaching-out and drawing through shallow circulation of the water. The fluoritemineralization of Mesozoic volcanic rock terrain is related mainly to the former mechanism, with the mineraliz-ing material coming chiefly from the Precambrian metamorphic rocks of the basement underlying the hostrocks; while that of Yanshanian granite terrain is associated with the latter mechanism, with the mineralizingmaterial derived primarily from the host granites and sedimentary rocks.

关键词： Minerogenetic Model for Two Types of Fluorite Deposits in Southeastern China

METALLOGENETIC MECHANISM OF LIANHUASHAN PORPHYRY TUNGSTEN DEPOSIT

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 1985年第11期28卷 1207-1217页

作者：谭运金 Ministry of geology and mineral resources Yichang institute of geology and mineral resources

This article discusses the metallogenetic mechanism of Lianhuashan porphyry tungsten deposit on the basis of the studies of inclusion, stable isotope, mineralogy and trace *** Lianhuashan porphyry tungsten deposit originated in the hypabyssal to near surface condition. The temperature of alteration and mineralization of this deposit ranges from 150° to 650℃, indicating that the alteration and mineralization have experienced from the latemagmatic stage to the post-magmatic mesothermal *** fO, fSand pH values of metallogenetic liquid of Lianhuashan porphyry tungsten deposit are logfO=—26——42, logfS=—17——7 and pH=4.5—7.5. The ferberite mineralization was formed when logfO=—26——31, pH=4.5—5, while the scheelite and sulfides mineralization was formed when logfO=—38——42, pH=7—7.5.

关键词： METALLOGENETIC MECHANISM OF LIANHUASHAN PORPHYRY TUNGSTEN DEPOSIT OC

Discovery and Significance of Malan Loess on the Piedmont Plain in Pinggu District, Beijing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2014年第5期88卷 1565-1578页

作者： LU Lu ZHAO Yuanyi WANG Xiaoliang ZHAO Xitao YANG Zhenjing WANG Chengmin BI Zhiwei LU Wenhui institute of mineral resources Chinese Academy of Geological Sciences Beijing institute of geology Liaoning institute of geology and mineral resources institute of geology and Geophysics Chinese Academy of Sciences institute of Hydrogeology and Environmental geology Chinese Academy of Geological Sciences No.3 geology and mineral Exploration institute of Gansu Provincial Bureau of geology and mineral

The platforms on both sides of the Malangou River （a lateral ditch of the Qingshui River that is a tributary of the Yongding River） where Malan Village in Zhaitang Town of Mentougou District of Beijing is located are the place of China＇s typical section of the Quaternary Malan loess. During the investigation in the eastern suburbs of Beijing City, the authors not only clarified 5 grades of terraces on the Pinggu piedmont plain, but also found a clayey silt section mixed with a small amount of alluvial-diluvial gravel layers at a height of 15-25 m above the river level near a Fishpond in Xinli Village of Nandule Town. Results of the study of grain size of the section document that the loess mostly is silty soil （0.05--0.005 mm）, and that the grain size probability cumulative curves of the section are dominated by single-peak, coarse-grained segment I and coarse-grained segment II types, reflecting that its depositional environment is similar to eolian phase. Identification results of heavy minerals from the section show that their contents account for 0.01%-0.11%, averaging 0.04%. There are 24 kinds of heavy minerals, most of which are stable heavy minerals, and the clay minerals mostly are illite, which is consistent with the Malan loess on the Loess Plateau. The chemical composition data reflect that the source area of the loess is relatively arid. The six grade classification of sporopollen in the section further shows the subdivision of the history of alternating warm and humid phases in this geological period. The thermoluminescence dating results range from 21.0 ka to 59.2 ka, convincingly demonstrating that the section indeed consists of Malan loess. The above studies provide a new basis for overall understanding of the distribution of the Malan loess at the northeast margin of the North China Plain and its environment change in the Late Pleistocene.

关键词： eolian loess Malan loess formation environment Pinggu

Cretaceous desert cycles, wind direction and hydrologic cycle variations in Ordos Basin: Evidence for Cretaceous climatic unequability

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第8期47卷 727-738页

作者： JIANG Xinsheng PAN Zhongxi XIE Yuan LI Minghui institute of Sedimentary geology Chengdu University of TechnologyChengdu 610059China Chengdu institute of geology and mineral resources CGSChengdu 610082China Chengdu Institute of Geology and Mineral ResourcesCGSChengdu 610082China Chengdu Institute of Geology and Mineral ResourcesCGSChengdu 610082China Chengdu Institute of Geology and Mineral ResourcesCGSChengdu 610082China

Climatic state under greenhouse effect is a currently hot point. Whether greenhouse climate in geological history, especially in Cretaceous, was equable or not has aroused extensive discussion. By analysis on depositional cyclcity, wind direction change and hydrologic cycle variation of Cretaceous desert in the Ordos Basin of China, the unequability of Cretaceous cli-mate is dealt. It is shown that Cretaceous climate was extremely cyclic, not only having long and mid term but also having strong seasonal even instantaneous changes. Therefore, it is sug-gested that Cretaceous climate was not equable.

关键词： Ordos Basin of China,Cretaceous desert cycle,wind direction change,hydrologic cycle variation,Cretaceous climatic unequability.