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On the siltation of the middle Yangtze River

Science china Earth Sciences 2004年第5期47卷 463-480页

作者： YIN Hongfu1, CHEN Guojin2, LI Chang抋n1 & WEI Yuan3.1. School of Earth Sciences, china University of Geosciences, Wuhan 43.074, china 2. Hydrogeological Team, Hubei Bureau of Geology and Mineral Resources, Jingzhou 43.100, china 3. geological survey of jiangxi province, nanchang 3302.1, china china Univ Geosci Sch Earth Sci Wuhan 430074 Peoples R China Hubei Bur Geol & Mineral Resources Hydrogeol Team Jinzhou 434100 Peoples R China Geol survey jiangxi province Nanchang 3300201 Peoples R China

About 5.2×108 t/a of silts from the upper reach of the Yangtze River are transported through Yichang into the middle Yangtze River. The middle Yangtze itself and its tributaries yield ca. 0.8×108 t silts annually. Of this total 6×108 t/a input of silts, ca. 1.2×108 t/a are deposited within the river artery and lakes, while ca 4.83.108 t/a are at first transported into the lower reach through Datong, and then either deposited along the river and the Yangtze Delta, or output into the sea. Along the middle Yangtze River silting generally exceeds scouring, but the spatial and temporal distributions of scour-and-fill, as well as its distribution in the river valley transections, are uneven. Along the Yichang-Chenglingji and Jiujiang-Datong Segments of the middle Yangtze, scouring exceeds or equals silting. Silting mainly occurs along the Luoshan-Wuhan-Huangshi Segments with Wuhan as the pivotal point, as well as in the Dongting and Poyang Lakes. Even in these silting-dominated areas, there are times and parts of segments that scouring prevails. As to the transections, generally the river channel of main stream is scouring-dominated, forming V-shaped sections to a depth of 203. m or more, whereas the floodplains and bar islands are silting-dominated, forming wide and relatively high flats, which are often artificially transformed into protected embankments. Because the Jingjiang Levee separates the Jianghan Plain from Yangtze to the south, little has been deposited in that plain except a few sediments from the Han River—a tributary of the middle Yangtze. This factor plus the tectonic sag of that plain has made the altitude of plain surface several meters lower than that of the levee in most of the areas. Sil-tation along the Luoshan-Wuhan-Huangshi Segments has resulted in the elevation of flood level in this and upstream segments. River channel scouring plus floodplain silting have caused the transections of the middle Yangtze valley typically with deep channel and height

关键词： the middle Yangtze, scour-and-fill, siltation, silt utilization.

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Age of Yingfeng rapakivi granite pluton on the north flank of Qaidam and its geological significance

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Science china Earth Sciences 2004年第4期47卷 357-365页

作者： XIAO Qinghui1,2, LU Xinxiang1,3. WANG Fei4, SUN Yangui5, WEI Xiangdong3.& XING Zuoyun6 1. Division of Granite Geology, china geological survey, Yichang 443.03. china 2. Information Center of Ministry of Land and Resources, Beijing 100812, china 3. geological survey of Henan province and Institute of geological Research of Henan province, Zhengzhou 450053. china 4. geological Institute, china Seismological Bureau, Beijing 100029, china 5. geological survey Institute of Qinghai province, Xining 81003., china 6. china University of Geosciences, Wuhan 43.074, china Division of Granite Geology China Geological Survey Yichang 443003 China Information Center of Ministry of Land and Resources Beijing 100812 China geological survey of Henan province and Institute of geological Research of Henan province Zhengzhou 450053 China geological Institute China Seismological Bureau Beijing 100029 China geological survey Institute of Qinghai province Xining 810032 China china University of Geosciences Wuhan 430074 China

The Yingfeng rapakivi granite on the north flank of Qaidam is a newly discovered Proterozoic rapakivi pluton in china, which was found after the discovery of Shachang rapakivi in Miyun County, Beijing and Kuandian rapakivi in Jilin province. Yingfeng rapakivi pluton is ex-posed on the north side of the suture belt between Qinling-Kunlun orogenic belt and North china plate. U-Pb zircon isotopic dating and Ar-Ar isotopic dating of both hornblende and K-feldspar from the Yingfeng rapakivi granite have been conducted. The results show that the age of (1776±3.)Ma at the upper intercept in Concorde diagram represents the age of formation of the plu-ton, whereas the age of (526 281) Ma at the lower intercept and Ar-Ar mineral dating of horn-blende and K-feldspar correspond to the age of a later event affecting the pluton, suggesting that Yingfeng pluton has ever been affected by strong regional Caledonian-Hercynian tectonic movement after its formation. The discovery of middle Proterozoic Yingfeng rapakivi granite pro-vides a petrologic evidence for the timing of cratonization of both the continental crust basement in western china and the basement of the North china plate and for a rifting event taking place in the mid-Proterozoic, suggesting that an amalgamation of ancient china continents had ever happened during the L liang Movement?between the early Proterozoic and the mid-Proterozoic.

关键词： rapakivi, U-Pb dating, Ar-Ar dating, Kunlun-Qinling orogenic belt.

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REE Geochemistry in the Weathered Crust of Granites, Longnan Area,jiangxi province

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Acta Geologica Sinica(English Edition) 1990年第2期64卷 193-209,237页

作者： Wu Chengyu Huang Dianhao Guo Zhongxun Institute of Mineral Deposits, Chinese Academy of geological Sciences, Beijing geological survey Party of South {3., {3. Bureau of Geology and Mineral Resources, Ganzhou, {3. jiangxi BUR GEOL & MINERAL RESOURCES GEOL SURVEY PARTY S JIANGXIGANZHOUPEOPLES R CHINA

Warm and humid climate and gentle hilly topography have provided favourable conditions for the devel-opment of the weathering crust of the granite intrusions in the Longnan area, jiangxi province. REE is mostlyconcentrated in an adsorption state in clay in the wholly weathered zone. The rare-earth minerals enriched inthe parent rocks provided the source material for the REE enrichment. Exchangeable REE accounts for48-86%. Extraction experiments and stable isotopic study of clay minerals suggest that the downward infiltra-tion of meteoric water and increasing gradient of pH values have played an important role in the enrichment ofREE during the progressive weathering. Slight fractionation of individual REE can not change their distribu-tion patterns in the profiles. which are inherited from the parent rocks.

关键词： REE Geochemistry in the Weathered Crust of Granites Longnan Area,jiangxi province

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A new species of Macrocnemus (Reptilia: Protorosauria) from the Middle Triassic of southwestern china and its palaeogeographical implication

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Science china Earth Sciences 2007年第11期50卷 1601-1605页

作者： LI Chun1, ZHAO LiJun2 & WANG LiTing3.1 Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, china 2 Zhejiang Museum of Nature History, Hangzhou 3.0012, china 3.geological {3. of Guizhou province, Guiyang 550005, china 1. Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing 100044 China 2. Zhejiang Museum of Nature History Hangzhou 310012 China 3. geological survey of Guizhou province Guiyang 550005 China

A new species of the terrestrial protorosaur Macrocnemus is briefly described and named Macrocne-mus fuyuanensis sp. nov. The specimen was found from the marine Triassic of Yunnan province, southwestern china. It differs from the type species M. bassanii in having the following characters: (1) 17 or 18 dorsal vertebrae; (2) relatively long humerus; and (3. femur longer than tibia. M. fuyuanensis is the only record of the genus outside Monte San Giorgio area and the first definite terrestrial reptile found from the marine Triassic of china. The age of the fossil-bearing Zhuganpo Member of the Falang Formation is believed to be the Ladinian based on associated vertebrate fauna. The existence of Mac-rocnemus in the limestone suggests the presence of a terrestrial ecosystem which probably originated from the Anisian and well developed in the Ladinian in this region. The island system along the north-coast of Tethyan during the Triassic was probably an important route for the exchanges of reptiles, especially the terrestrial reptiles between the west and east.

关键词： Protorosauria,Middle Triassic,Ladinian,Yunnan,terrestrial reptile

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Carbon isotope composition of the Lower Triassic marine carbonates, Lower Yangtze Region, South china

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Science china Earth Sciences 2006年第3期49卷 225-241页

作者： ZUO Jingxun1,2, TONG Jinnan3. QIU Haiou4 & ZHAO Laishi3.1. Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, china 2. Henan Institute of geological survey, Zhengzhou 450007, china 3. State Key Laboratory of geological Processes and Mineral Resources at china University of Geosciences, Wuhan 43.074, china 4. Faculty of Material Sciences and Chemical Engineering, china University of Geosciences, Wuhan 43.074, china 1. Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China 2. Henan Institute of geological survey Zhengzhou 450007 China 3. State Key Laboratory of geological Processes and Mineral Resources at china University of Geosciences Wuhan 430074 China 4. Faculty of Material Sciences and Chemical Engineering China University of Geosciences Wuhan 430074 China

Studies on three Lower Triassic sections located on the shallow water platform, the deep water slope and in the deep water basin in the Lower Yangtze Region, South china, show the similar trend of carbon isotope evolution. Biostratigraphic correlations among the Lower Triassic sections on the basis of standard conodont zones indicate that three negative shifts occurred in the Griesbachian, the Smithian and the late Spathian stages respectively, and one distinctly positive shift occurred in the early Spathian stage. Trend of carbon isotope evolution of the Lower Triassic reflects some significant changes in the global carbon cycle. Moreover, δ 13. background values are intensively controlled by palaeogeographic environment. In general, δ 13. values from deep-water slope carbonates are lighter than those from carbonate platform and heavier than those from deep-water basin carbonates. The positive carbon isotope excursion may be induced by a significant amount of organic carbon burial in marine sediments and increase in primary productivity. The large negative carbon isotope excursions during the Early Triassic in Lower Yangtze Region are interpreted to relate to volcano eruptions based on tuffaceous claystone interlayers observed near the Permian-Triassic boundary, the Induan- Olenekian boundary and the Lower Triassic-Middle Triassic boundary.

关键词： Lower Triassic, carbon isotope compositions, palaeogeography, volcanic eruptions, Lower Yangtze Region.

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The tectonic settings and seismogenic tectonics of the M5.7 Jiujiang earthquake in 2005,jiangxi province,china

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Science china Earth Sciences 2008年第5期51卷 640-653页

作者： LI ChuanYou1, ZENG XinFu2 & ZHANG JianXi3.1 Institute of Geology, china Earthquake Administration, Beijing 100029, china 2 jiangxi Earthquake Administration, {3. 3.003., china 3.Beijing Earthquake Administration, Beijing 100080, china 1. Institute of Geology China Earthquake Administration Beijing 100029 China 2. jiangxi Earthquake Administration Nanchang 330039 China 3. Beijing Earthquake Administration Beijing 100080 China

The M5.7 Jiujiang earthquake in 2005 was a mid-strong one, stronger than expected to occur in the region. This paper discusses the neo-tectonic settings of this earthquake, and it is thought that the earthquake region is located in the transitional belt, a potential area inducing weak to moderately strong earthquakes, between two large different tectonic units. The results of the reconnaissance work and on-the-spot investigation after earthquake indicate that the occurrence of the M5.7 Jiujiang earth- quake is closely related with the NE-trending fault on the western margin of Ruichang Basin. From its controlling to the landforms and Quaternary depositions, geological profiles, ESR dating, etc., the ac- tivity of the Dingjiashan-Langjunshan fault bounding the basin is discussed. It suggests that this fault displays an active one in Middle Pleistocene by the outcrop. Based on the activity of the fault, and the direction and location of the ground fissures, the isoseismal lines and the nodal plane of the focal mechanism solution, it is inferred that the Dingjiashan-Langjunshan fault is the seismogenic tectonics of the M5.7 Jiujiang earthquake, and the intersection point between this fault and the active NW ones is the possible origin of location of this earthquake. Our study shows that this earthquake is not an event exceeding expectation, and that the active and invisible characteristics of the causative fault are typical in the eastern area of china.

关键词： Jiujiang earthquake tectonic settings Dingjiashan-Langjunshan fault activity seismogenic tectonics

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REE Geochemistry and Mineralization Characteristics of the Zudong and Gnanxi Granites, jiangxi province

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Acta Geologica Sinica(English Edition) 1989年第2期63卷 139-157页

作者： Huang Dianhao, Wu Chengyu Institute of Mineral Deposits, Chinese Academy of geological Sciences, Beijing and Han Jiuzhu Southern jiangxi geological {3. Party, jiangxi Bureau of Geology and Mineral Resources, Ganzhou Zhang Zhong min Institute of Mineral Deposits Chinese Academy of Geological Sciences Beijing China

The Zudong and Guanxi granites are original rocks of the ion adsorption-type HREE and LREE deposits in weathering crust of granites. The ΣREE value and LREE/HREE ratio of the Zudong granite are 264 ppm and 0.81-0.24 respectively, and the average Y/ΣREE ratio is 3..8-54.5%. This is mainly due to magmatic crystallization and evolution and deuteric metasomatism (albitization, muscovitization and fluorite-doveritization). These alterations resulted in endogenic mineralizations of yttrium-group REE fluorine carbonates, silicates and arsenates. The Guanxi granite is characterized by LREE enrichment (the average LREE/HREE ratio is 2.43..

关键词： REE Geochemistry and Mineralization Characteristics of the Zudong and Gnanxi Granites jiangxi province

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Timing and geochemical characters of the Sanchazi magmatic arc in Mianlüe tectonic zone,South Qinling

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Science china Earth Sciences 2004年第4期47卷 317-328页

作者： LI Shuguang1, HOU Zhenhui1, YANG Yongcheng2, SUN Weidong1,1), ZHANG Guowei3. & LI Qiuli1 1. School of Earth and Space Sciences,University of Science and Technology of china ,Hefei 23.026,china 2. Regional geological {3. Team of Shaanxi province,Xianyang 712000, china 3. Department of Geology, Northwest University,Xi抋n 710069, china Present address: Max-Planck-Institut f. Chemie Postfach 3060 55020 Mainz Germany School of Earth and Space Sciences University of Science and Technology of China Hefei 230026 China Regional geological survey Team of Shaanxi province Xianyang 712000 China Department of Geology Northwest University Xi’an 710069 China

The Sanchazi mafic-ultramafic complex in Mianlüe tectonic zone,South Qinling can be subdivided into two blocks,*** paleo-magmatic arc and Zhuangkegou paleo-oceanic crust fragment (ophiolite).The Sanchazi paleo-magmatic arc is mainly composed of ande-site,basaltic and basalt-andesitic gabbro(or diorite),andesitic dyke,plagiogranite and minor ul-tramafric rocks,which have typical geochemical features of island arc volcanic rocks,such as high field strength element(***,Ti)depletions and lower Cr,Ni *** Light rare earth element (LREE) and K enrichments of these rocks and zircon xenocrystals of 900 Ma from plagiogranite suggest that this magmatic arc was developed on the South active continental margin of the South Qinling *** U-Pb age of (3.0±61) Ma for zircons from plagiogranite in-dicates that the Mianlüe paleo-oceanic crust was probably subducted underneath the South Qinling micro-continent in *** is consistent with the formation time (3.9Ma) of the Huwan eclogite originating form oceanic subduction in Dabie Mountains,suggesting that the Mianlüe paleo-ocean probably extended eastward to the Dabie Mountains in *** high-Mg adakitic rocks in Sanchazi paleo-magmatic arc suggest thet the subducted oceanic crust was relatively young (<25Ma) and hot.

关键词： Qinling orogen, magmatic arc, U-Pb zircon age, ophiolite complex.

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Vermicular fossils in the Early Cambrian Xidashan Formation in the Quruqtagh region of Xinjiang, china

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Progress in Natural Science:Materials International 2006年第5期16卷 559-562页

作者： YANG Ruidong, ZHANG Chuanlin, SONG Guoqi and LUO Xinrong (Postgraduate School of Guizhou University, Guiyang 550025, china Nanjing Institute of Geology and Mineral Resources, Nanjing 210016, china geological {3. of No. 3.geological Party, Xinjiang, Kurle 841000, china) [a]Postgraduate School of Guizhou University Guiyang China [b]Nanjing Institute of Geology and Mineral Resources Nanjing China

Large amounts of vermicular fossils and a minor amount of sponge animal fossils have been found in the Early Cambrian Xidashan Formation in the region of Quruqtagh, Xinjiang. Vermicular fossils are generally more than 50 mm long and 0. 3.1. 4 mm wide; their wrinkled lamellae are microfine with 3.10 pieces within the length of every each millimeter. The fossils are considered to be Sabellidites cambriensis Sokolov (1965) . The Xidashan Formation is the highest stratum in which Sabellidites occur, as has been so far reported.

关键词： vermicular fossil Early Cambrian Quruqtagh Xinjiang.

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^(40)Ar/^(3.)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance

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Science china Earth Sciences 2004年第9期47卷 794-803页

作者： ZHANG Yueqiao1, CHEN Wen2, 3.& YANG Nong1 1. Institute of Geomechanics, Chinese Academy of geological Sciences, Beijing 100081, china 2. Institute of Geology, Chinese Academy of geological Sciences, Beijing 10003., china 3. Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, china Institute of Geomechanics Chinese Academy of Geological Sciences Beijing 100081 China Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12-10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 3.0℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.

关键词： Xianshuihe fault zone, Zheduoshan granitic massif, sinistral shear deformation, 40Ar/3.Ar dating, late Cenozoic.

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