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| 1 | Paleogene-Neogene stratigraphic realm and sedimentary sequence of the Qinghai-Tibet Plateau and their response to uplift of the plateau显示文摘Based on the data of 1:250000 geological mapping completed by CGS and the previous literature of the Cenozoic strata, 98 remnant basins and 5 stratigraphic realms with 13 stratigraphic subrealms have been recognized on the Qinghai-Tibet Plateau and its adjacent area. Through the research of the types of remnant basins, tectonic setting, stratigraphic sequence and sedimentary characteristics, contact relationship between the strata, the formation time and evolution history of sediments, we divided the uplift process and sedimentary response of the Qinghai-Tibet Plateau into 3 stages and 8 sub-stages, namely, subduction-collision uplift stage (65-34 Ma) with three sub-stages, intercontinental convergence and compressive uplift stage (34-13 Ma) with three sub-stages, and intercontinental isostatic adjustment uplift stage (since 13 Ma) with two sub-stages. | ZHANG KeXin WANG GuoCan JI JunLiang LUO ManSheng KOU XiaoHu WANG YueMing XU YaDong CHEN FenNing CHEN RuiMing SONG BoWen ZHANG JianYu LIANG YinPing | 2010 | Science China Earth Sciences2010,53,9: | 49 |
| 2 | Deep water bottom current deposition in the northern South China Sea显示文摘There are some active bottom currents on the northern continental slope of the South China Sea (SCS). Reflection seismic profiles show that the bottom current channels occur in the water depth range of 1000 to 2700 m,extending from the NE to the SW,leading to accumulation of discontinuous drifts with higher sedimentation rates on the eastern side of the channel. The stacking pattern of the layers sug-gests that these drifts propagated southwestward,following the direction of the bottom currents. One sedimentary drift to the southeast of the Dongsha Islands has the highest sedimentation rate of 97cm/ka in the last 12 ka. The sedimentary characteristics of the sediment layers indicate that these bottom currents are most likley caused by the water movement of a branch of the West Pacific Ocean Current,which enters the northern SCS via the Bashi Strait. Once formed,the bottom currents trans-port sediments along the northern slope of SCS southwestward and finally disappear into the central basin of the SCS. Due to the bottom current activity,the deep-sea sedimentary process in the northern SCS is complex. | SHAO Lei LI XueJie GENG JianHua PANG Xiong LEI YongChang QIAO PeiJun WANG LiaoLiang WANG HongBin | 2007 | Science China Earth Sciences2007,50,7: | 43 |
| 3 | 西昆仑-塔西南坳陷晚古生代以来的沉积构造演化显示文摘自柯克亚深层油气勘探取得突破以来,塔西南坳陷一直受到各类地质学家的广泛关注,有关该盆地的形成和演化历史及其油气资源评价近年来更是成为人们的研究热点。本文在总结前人资料的基础上,探讨塔西南和西昆仑地区自晚古生代以来所经历的构造及沉积格架的演变过程,对塔西南坳陷性质及其演化阶段划分所存在的争议进行了归纳,分析了塔西南-西昆仑这一盆山体系形成和演化中的构造变形和沉积记录。总体来说,根据现有沉积和构造变形资料,中生代之前西昆仑和塔西南坳陷分别处于同一构造背景下的不同沉积单元;二者之间盆山体系的形成主要自晚侏罗世-早白垩世,中-上新世是造盆造山作用机制发生重大转折的时期,或者说早更新世末的构造运动基本上奠定了西昆仑-塔里木盆地南缘现今的盆-山构造格架。 | 方爱民 马建英 王世刚 赵越 胡健民 | 2009 | 岩石学报2009,25,12: | 40 |
| 4 | 江西井冈山地区早古生代沉积岩的地球化学特征及其对沉积环境的制约显示文摘本文研究的井冈山地区位于华夏地块中部,在早古生代寒武纪-奥陶纪时期沉积了巨厚的泥砂质韵律岩层夹碳酸盐岩和含碳岩层。它们具有较高的SiO_2(53.12%~86.37%,平均为70.16%)和Al_2O_3含量(5.43%~22.70%,平均为13.54%),高的Al_2O_3/(CaO+Na_2O)(1.36~174.6,平均为45.5)与K_2O/Na_2O比值(1.0~64.7,平均为20.4)以及低的TiO_2(0.30%~0.95%,平均为0.62%)和CaO含量(0.05%~6.05%,平均为0.63%)。它们具有与上地壳相似的微量元素和稀土元素组成,即富集大离子亲石元素和轻稀土元素,铕负异常明显。它们的主量元素、微量元素和稀土元素特征显示其沉积环境主要为被动大陆边缘浅海环境,物源区被剥蚀物质以上地壳成分为主。根据研究区内早古生代沉积物中没有蛇绿岩和火山岩、Ce异常较弱、有机碳的δ^(13)C_(org)值较低(-30.2‰~-25.4‰)、以及在沉积物中普遍发育的浅海沉积标志,如波痕、荷重模、泥砾、小型斜层理、含腕足类和腹足类等生物化石的灰岩透镜体等,认为研究区在早古生代时期不是洋盆,而是浅海-半深海或陆壳海槽,是由成冰纪时期的裂解事件,使原先的华南地块被肢解成许多次级块体(如武夷、赣中南、云开等)、各块体间成为浅海盆地的结果。 | 沈渭洲 舒良树 向磊 张芳荣 王博 | 2009 | 岩石学报2009,25,10: | 33 |
| 5 | Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau显示文摘Geological mapping data (1:250000) in the Qinghai-Tibet Plateau and its adjacent regions reveal the sediment sequences, distribution and tectonic evolution of the 92 Tertiary remnant basins. Southern Tibet and the Yecheng area in Xinjiang, located at southern and northwestern margins of the Qinghai-Tibet Plateau, respectively, were parts of the Neo-Tethys remnant sea in the Paleogene. In southern Tibet, both the subabyssal and abyssal sequences occur at the Gyangze, Saga, Guoyala, and Sangmai areas. The deep-water facies successions outcrop in the west, whereas the shallow-water facies sequences in the east, indicating the east to the west retreat of the Neo-Tethys Ocean. The retreat of the Neo-Tethys Ocean in the east was contributed to the earlier tectonic uplift of the eastern Qinghai-Tibet Plateau. The uplift process of the Plateau from the Late Cretaceous to Pliocene is described as follows: During the Late Cretaceous, tectonic uplift of the Qinghai-Tibet Plateau occurred in the northeastern part and the configuration of the Qinghai-Tibet Plateau was characterized by rise in the northeast and depression in the west. In the Paleocene-Eocene interval, the Tengchong-Baingoin and Kuyake-Golmud areas experienced local tectonic uplifting, the West Kunlun uplift zone broadened easterly, the Qilian uplift zone broadened southerly, and the Songpan-Garzê uplift zone shrank easterly. The Oligocene configuration of the Qinghai-Tibet Plateau was characterized by mountain chains rising along its margins and sedimentary basins in the central part because of tectonic uplifts of the Gangdisê and the Himalaya blocks. Meanwhile, the Kunlun-Altyn-Qilian uplift zones have also broadened southerly and northerly. In contrast, the great uplift zones of the Gangdisê, the Himalaya, the Karakorum, and the Kunlun blocks characterize the paleogeographic contours of the Qinghai-Tibet Plateau during the Miocene-Pliocene. Additionally, the thermochronological data on tectonic uplift events in southern Tibet, West Kunlun Mountains, Altyn Tagh, eastern Tibet, and western Sichuan all suggest that the most intense deformation occurred at 13-8 Ma and since 5 Ma, respectively, corresponding to two great uplift periods in Neogene. As a result, turnover of paleogeographic configuration of the Qinghai-Tibet Plateau occurred during the Neogene, experiencing a change from high contours in the east in the pre-Oligocene to high contours in the west at the end-Pliocene. The uplift of the Qinghai-Tibet Plateau during the Cenozoic was episodic, and the uplifts of various blocks within the Plateau were spatially and chronologically different. | ZHANG KeXin WANG GuoCan CAO Kai LIU Chao XIANG ShuYuan HONG HanLie KOU XiaoHu XU YaDong CHEN FenNing MENG YanNing CHEN RuiMing | 2008 | Science China Earth Sciences2008,51,11: | 31 |
| 6 | Hydrogen isotope composition of natural gases from the Tarim Basin and its indication of depositional environments of the source rocks显示文摘By measuring carbon and hydrogen isotope compositions for C1, C2 and C3 of 74 gas samples, natural gases from the Tarim Basin can be divided into six groups on the basis of their origins: (1) coal-type gas derived from coal measures; (2) coal-type gas generated from the T-J lacustrine mudstones; (3) oil-type gas derived from the Cambrian and low Ordovician marine source rocks; (4) oil-type gas from the source rocks deposited in the marine-transitional facies; (5) mixing gas between gas derived from the Carboniferous transitional source rocks and the Mesozoic humic gas, and (6) mixing gases of thermal genetic gas and little deep gas in the Southwest depression of the Tarim Basin. The δ D values of methane in natural gases originating from different type kerogens are affected by both palaeo-environments of the source rock formation (kerogen types) and thermal maturity, with sedimentary environment (kerogen type) as the main controlling factor. Under the similar thermal maturity, the hydrogen isotope composition of methane is more enriched in deuterium in marine environments than lacustrine one. With the increase of thermal maturity and the increase of carbon atomic numbers of gaseous alkanes, the hydrogen isotopes become enriched in deuterium. The δ D values of ethane and propane (δ D2, δ D3) are controlled mainly by thermal maturity and to a lesser degree by sedimentary environment of the source rock formation. The partial reversal of hydrogen isotopes for gaseous alkanes would be related to the microbial oxidation, mixing of sapropelic and humic gases and / or mixing of gases from similar kerogen sources with various thermal maturities. In the oil-type gas, the sulfate reduction reaction would result in the reversed order of δ D1 and δ D2 (e.g. δ D1>δ D2). | LIU QuanYou DAI JinXing LI Jian ZHOU QingHua | 2008 | Science China Earth Sciences2008,51,2: | 28 |
| 7 | Late Triassic sedimentary records in the northern Tethyan Himalaya:Tectonic link with Greater India显示文摘The Upper Triassic flysch sediments(Nieru Formation and Langjiexue Group)exposed in the Eastern Tethyan Himalayan Sequence are crucial for unraveling the controversial paleogeography and paleotectonics of the Himalayan orogen.This work reports new detrital zircon U-Pb ages and whole-rock geochemical data for clastic rocks from flysch strata in the Shannan area.The mineral modal composition data suggest that these units were mainly sourced from recycled orogen provenances.The chemical compositions of the sandstones in the strata are similar to the chemical composition of upper continental crust.These rocks have relatively low Chemical Index of Alteration values(with an average of 62)and Index of Compositional Variability values(0.69),indicating that they experienced weak weathering and were mainly derived from a mature source.The geochemical compositions of the Upper Triassic strata are similar to those of graywackes from continental island arcs and are indicative of an acidicintermediate igneous source.Furthermore,hornblende and feldspar experienced decomposition in the provenance,and the sediment became enriched in zircon and monazite during sediment transport.The detrital zircons in the strata feature two main age peaks at 225-275 Ma and 500-600 Ma,nearly continuous Paleoproterozoic to Neoproterozoic ages,and a broad inconspicuous cluster in the Tonian-Stenian(800-1200 Ma).The detrital zircons from the Upper Triassic sandstones in the study area lack peaks at 300-325 Ma(characteristic of the Lhasa block)and 1150-1200 Ma(characteristic of the Lhasa and West Australia blocks).Therefore,neither the Lhasa block nor the West Australia blocks likely acted as the main provenance of the Upper Triassic strata.Newly discovered Permian-Triassic basalt and mafic dikes in the Himalayas could have provided the 225-275 Ma detrital zircons.Therefore,Indian and Himalayan units were the main provenances of the flysch strata.The Tethyan Himalaya was part of the northern passive margin and was not an exotic terrane separated from India during the Permian to Early Cretaceous.This evidence suggests that the Neo-Tethyan ocean opened prior to the Late Triassic and that the Upper Triassic deposits were derived from continental crustal fragments adjacent to the northern passive continental margin of Greater India. | Huawen Cao Yong Huang Guangming Li Linkui Zhang Jianyang Wu Lei Dong Zuowen Dai Liu Lu | 2018 | Geoscience Frontiers2018,9,1: | 27 |
| 8 | The characteristics and recognition of internal-tide and internal-wave deposits显示文摘Internal-tide and internal-wave deposits are a new and important type of deep-water traction-current deposits. Based on an analysis of documented internal-tide and internal-wave deposits, five facies types can be recognized: ( ⅰ ) bidirectional cross-laminated sandstone facies, ( ⅱ ) unidirectional cross-bedded and cross-laminated sandstone facies, ( ⅲ ) rhythmic alternating sandstone facies and mudstone, ( Ⅳ ) flaser, wavy and lenticular bedded foraminiferal limestone facies, ( Ⅴ ) sandy oolitic limestone facies with flaser, wavy and lenticular bedding and epsilon cross bedding, which formed in submarine channel, unchannelized continental slope and plateau environments respectively. Accoding to the available data and knowledge,three sedimentation models are built; some discriminating characteristics of internal-tide and internal-wave deposits, and the distinction between them and contourites and turbidites are summed up. | He, YB Gao, ZZ | 1999 | Chinese Science Bulletin1999,44,7: | 23 |
| 9 | Natural gas origins of large and medium-scale gas fields in China sedimentary basins显示文摘China sedimentary basins present abundant natural gas resource thanks to its unique geological settings.Marine highly-matured hydrocarbon source rocks,widespread coal-measure strata and low temperature Quaternary saline strata,etc.,indicate the wide foreground of China natural gas resources. Up to now,most of the petroliferous basins have been discovered to have wholesale natural gas accumulation from Precambrian,Paleozoic,Mesozoic to Cenozoic in the east,the central,the west and the coast of China.These large and medium-scale gas reservoirs are mainly composed of hydrocarbon gas with big dry coefficient,tiny non-hydrocarbon,wide carbon isotope distribution and varying origin types,the hydrocarbon gas includes coal-formed gas,oil-formed gas,biogenic gas and inorganic gas, etc.Coal-formed gas is the main type of China natural gas resources,in particular several explored large-scale gas fields(>100 billion cubic meter)of Kela 2,Sulige and Daniudi,etc.,they all belong to coal-formed gas fields or the gas fields consisting mostly of coal-formed gas.Oil-formed gas is also abundant in China marine basins,for example marine natural gas of Sichuan Basin generated from crude oil cracking gas.Primary and secondary biogenic gas fields were discovered respectively in the Qaidam Basin and Western Slope of Songliao Basin.In addition,inorganic gases are mainly distributed in the eastern China,in particular the Songliao Basin with abundant carbon dioxide accumulation,indicating that the eastern China present large exploration potential of inorganic gas. | ZHANG ShuiChang &ZHU GuangYou Research Center of Research Institutes of PetroChina Exploration and Development,Beijing 100083,China | 2008 | Science China Earth Sciences2008,51,S1: | 21 |
| 10 | Lithofacies and sedimentary characteristics of the Silurian Longmaxi Shale in the southeastern Sichuan Basin,China显示文摘The Silurian Longmaxi Shale (SLS) is the target for shale gas exploration and exploitation in the southeastern Sichuan Basin.Based on detailed description of cores and outcrops,analysis of Gamma Ray (GR) logs,thin sections and mineralogical data,the SLS can be subdivided into six lithofacies:(1) clayey shale,(2) siliceous calcareous shale,(3) siliceous dolomitic shale,(4) silty-clayey interlaminated shale,(5) muddy siltstone,and (6) graptolite shale.Three facies associations are recognized in the study area,i.e.,inner shelf,outer shelf,and bathyal plain (including turbidite) facies.Outer shelf and bathyal plain facies dominate the lower interval of the SLS,while inner shelf facies dominates the upper part of the SLS.The thickness of the black shale in the northern part of the study area is the greatest,where siliceous calcareous shale,siliceous dolomitic shale,and graptolite shale are predominant.These three kinds of shale are rich in total organic carbon (TOC) content and brittle minerals,which is favourable for the accumulation of shale gas and its future exploitation. | Jiang Zaixing Guo Ling Liang Chao | 2013 | Journal of Palaeogeography2013,2,3: | 21 |
| 11 | Comprehensive geochemical identification of highly evolved marine carbonate rocks as hydrocarbon-source rocks as exemplified by the Ordos Basin显示文摘This study reversed the developing environments of hydrocarbon-source rocks in the Ordos Basin and evaluated carbonate rocks as hydrocarbon-source rocks and their distributions on account of the fact that China’s marine carbonate rocks as hydrocarbon-source rocks are character- ized by intensive thermal evolution and relatively low abundance of organic matter, by taking the Lower Paleozoic of the Ordos Basin for example and in light of the calculated enrichment coefficients of trace elements, the REE distribution patterns, the mathematical statistics analysis of elements and carbon isotopes and their three-dimensional diagrammatization in combination with the necessary organic parameters. As for the Ordos Basin, TOC=0.2% is an important boundary value. Studies have shown that in the strata where TOC is greater than 0.2%, Ba is highly enriched with positive δ 13Ccarb shifts and δ 13Corg less than ?28‰, reflecting a thigh paleo-productivity, high burial amounts of organic matter, relatively good hydrocarbon-generating potentiality and intensive REE fractionation. All these indicated that the settlement rates are low and the geological conditions are good for the preservation of organic matter, hence favoring the development of hydrocarbon-source rocks. The Klimory and Wulalik formations show certain regularities in those aspects and, therefore, they can be regarded as the potential effective hydrocarbon-source rocks. In the strata where total TOC is less than 0.2%, the contents of Ba are low, δ 13Ccarb values are mostly negative, and δ 13Corg values range from ?24‰― ?28‰, demonstrating low burial amounts of organic matter, poor potentialities of hydrocarbon gen- eration, weak REE fractionation and rapid settlement rates. These facts showed that most of the hy- drocarbon-source rocks were formed in shallow-water, high-energy oxidizing environments, thus un- favoring the development of hydrocarbon-source rocks. It is feasible to make use of the geochemical method to comprehensively assess the highly evolved marine carbonates rocks as potential hydro- carbon-source rocks and their distributions. | Tenger | 2006 | Science China Earth Sciences2006,49,4: | 20 |
| 12 | Tectonic uplift and sedimentary evolution of the Jiuxi Basin in the northern margin of the Tibetan Plateau since 13 Ma BP显示文摘Sediments shed from the northern margin of the Tibetan Plateau, the Qilian Mountains, are widely deposited in the foreland basin, the Jiuxi Basin, archiving plenty of information about the mountain surface uplift and erosion history. The Laojunmiao section, 1960 m thick, representing the upper sequence of the Cenozoic basin sediments, is paleomagnetically dated to about 13-0 Ma BP. Detailed sedimentary study of this sequence has revealed five sedimentary fades associations which determine four stages of sedimentary environment evolution. They are: (I) the half-deep lake system before 12.18 Ma BP, (Ⅱ) the shallow lake system between 12.18 and 8.26 Ma BP, (Ⅲ) the fan delta dominated sedimentary system in dry climate between 8.26 and 6.57 Ma BP, and (IV) alluvial fan system since 6.57 Ma BP. The associated mountain erosion and uplift are suggested to have experienced three phases, that is, tectonic stable (13-8.26 Ma BP), gradual uplift (8.26-<4.96 Ma BP), and rapid intermittent uplift (>3.66-0 Ma BP). | 宋春晖 方小敏 李吉均 高军平 赵志军 范马洁 | 2001 | Science China Earth Sciences2001,44,S1: | 20 |
| 13 | Sedimentary geochemistry of the Cambrian-Ordovician cherts: Implication on archipelagic ocean of North Qilian orogenic belt显示文摘The Caledonian North Qilian orogenic belt lies between the North China plate and the Qaidam mi-croplates, and resulted from the collision among the Qaidam microplate, mid-Qilian block and the North China plate. The orogen initiated from the rifting of the Late Proterozoic Rodinia, and then it experi-enced stages of Cambrian rift basin and Ordovician archipelagic oceanic basin, and foreland basin during Silurian to Early-Middle Devonian. The average ratios of Al/(Al+Fe+Mn), Al/(Al+Fe), δ Ce, Lan/Ybn and Lan/Cen from cherts of Cambrian Heicigou Formation are 0.797, 0.627, 1.114, 0.994 and 1.034 re-spectively. In the NAS standardized REE distribution pattern, the cherts from Xiangqianshan is slightly HREE enriched, and the cherts from Ganluci and Shiqingdong are plane. All of these features indicated that Cambrian cherts of the Heicigou Formation originated from a continental margin rift background. On the contrary, the average ratios of Al/(Al+Fe+Mn), Al/(Al+Fe), δ Ce, Lan/Ybn, Lan/Cen of the Ordovician chert from Dakecha, Cuijiadun, Shihuigou, Laohushan, Heicigou, Maomaoshan, Bianmagou, Da-chadaban, Baiquanmen, Jiugequan and Angzanggou, are respectively 0.72, 0.58, 0.99, 1.09 and 0.96 respectively. Their NAS standardized REE distribution patterns of most Ordovician cherts are plane mode or slightly HREE enriched. The REE distribution pattern of few samples of cherts are slightly LREE enriched. Characteristics of sedimentary geochemistry and tectonic evolution demonstrated that the Cambrian-Ordovician cherts, associated with rift, oceanic, island arc and back-arc volcanic rocks, was not formed in a typical abyssal oceanic basin or mid-oceanic ridge. On the contrary, they formed in a deepwater basin of continental margin or a archipelagic ocean tectonic setting. Several Early Paleo-zoic ophiolite belts in North Qilian and adjacent periphery Qaidam microplate imply that an archipelagic ocean during Ordovician existed in the east of Pro-Tethys. | DU YuanSheng1,2, ZHU Jie1, GU SongZhu1, 2, XU YaJun1 & YANG JiangHai1 1 Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China 2 Key Laboratory of Biogeology and Environment Geology of Education Ministry, Wuhan 430074, China | 2007 | Science China Earth Sciences2007,50,11: | 17 |
| 14 | Distribution and geological significance of 17α(H)-diahopanes from different hydrocarbon source rocks of Yanchang Formation in Ordos Basin显示文摘Based on GC-MS testing data of many saturated hydrocarbon samples, 17α(H)-C30 diahopanes (C30*) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but show remarkable differences in relative abundance among various source rocks. Generally, Chang 7 high-quality source rock (oil shale) developed in deep lake anoxic environment shows lower C30* content, whereas Chang 6-9 dark mudstone developed in shallow to semi-deep lake, sub-oxidizing environment shows relatively high to high C30* value. Particularly, Chang 7 and Chang 9 black mudstones in Zhidan region in the northeast of the lake basin show extremely high C30* value. A comparative analysis was made based on lithology, organic types and various geochemical parameters indicative of redox environment, and the results indicate that environmental factors such as redox settings and lithology are key factors that control the C30* relative abundance, while organic types and maturity may be minor factors. High to extremely high C30* values are indicative of sub-oxidizing environment of fresh-brackish water and shallow to semi-deep lake. Therefore, research on C30* relative content and distribution in lacustrine hydrocarbon source rocks in the Yanchang Formation, especially on the difference in C30* between Chang 7 high-quality source rocks (oil shale) and Chang 6-91 source rocks (dark mudstone), will provide an important approach for classification of Mesozoic lacustrine crudes and detailed oil-source correlation in the basin. | ZHANG WenZheng YANG Hua HOU LiHui LIU Fei | 2009 | Science China Earth Sciences2009,52,7: | 16 |
| 15 | Mesozoic radiolarian chert from the middle sector of the Yarlung Zangbo suture zone,Tibet and its tectonic implications显示文摘Three radiolarian fauna, aged as the Middle-Late Triassic, Late Jurassic-Early Creta- ceous and Cretaceous radiolarian fauna, have been recognised in the radiolarian cherts from the middle sector of the Yarlung Zangbo suture zone, southern Tibet, China. The average contents of SiO2 in the radiolarian cherts of the Middle-Late Triassic and Late Jurassic-Early Cretaceous are 90.24% and 92.58% respectively, with average ratios of Al/(Al+Fe+Mn) as 0.75 and 0.74 respectively, the average ratios of MnO/TiO2 as 0.36 and 1.24, the average ratios of Ce/Ce* as 1.15 and 1.03, and the average ratios of LaN/CeN as 0.85 and 0.93. These geochemical features indicate that both of them are biogenic, deposited in a continental margin basin. The SiO2 content of the Early Cretaceous radiolarian chert is 94.12%, with the ratio of Al/(Al+Fe+Mn) as 0.59, ratio of MnO/TiO2 as 4.30, ratio of Ce/Ce* as 0.60, ratio of LaN/CeN as 1.59, which imply that the chert is biogenic and was deposited in a pelagic basin. The Middle-Late Triassic association of the radiolarian chert and turbidites as well as their geochemical characteristics indicates the existence of a strong rifting marginal basin in the belt of the Yarlung Zangbo River then. The association of radiolarian chert and bedded basalt indicate an initial Tethyan ocean basin in southern Tibet during the Late Jurassic-Early Cretaceous. The early Cretaceous radiolarian chert coexisting with pillow basalt in top of the ophiolite suite represents sediments from the oceanic Tethyan basin. | ZHU Jie1,2, DU Yuansheng1, LIU Zaoxue2, FENG Qinglai1, TIAN Wangxue2, LI Jinping2 & WANG Changping2 1. Faculty of Earth Sciences,China University of Geology, Wuhan 430074, China 2. Hubei Institute of Regional Geology Survey, Wuhan 430034, China | 2006 | Science China Earth Sciences2006,49,4: | 15 |
| 16 | Jurassic sedimentary evolution of southern Junggar Basin:Implication for palaeoclimate changes in northern Xinjiang Uygur Autonomous Region,China显示文摘Junggar Basin,located in northern Xinjiang,presents continuous and multikilometer-thick strata of the Jurassic deposits.The Jurassic was entirely terrestrial fluvial and lacustrine deltaic sedimentation.Eight outcrop sections across the Jurassic strata were measured at a resolution of meters in southern Junggar Basin.Controlling factors of sedimentary evolution and palaeoclimate changes in Junggar Basin during the Jurassic were discussed based on lithology,fossils and tectonic setting.In the Early to Middle Jurassic,the warm and wide Tethys Sea generated a strong monsoonal circulation over the central Asian continent,and provided adequate moisture for Junggar Basin.Coal-bearing strata of the Badaowan,Sangonghe,and Xishanyao Formations were developed under warm and humid palaeoclimate in Junggar Basin.In the late Middle Jurassic,Junggar Basin was in a semi-humid and semi-arid environment due to global warming event.Stratigraphy in the upper part of the Middle Jurassic with less plant fossils became multicolor or reddish from dark color sediments.During the Late Jurassic,collision of Lhasa and Qiangtang Block obstructed monsoon from the Tethys Sea.A major change in climate from semi-humid and semi-arid to arid conditions took place,and reddish strata of the Upper Jurassic were developed across Junggar Basin. | Shun-Li Li Xing-He Yu Cheng-Peng Tan Ronald Steel | 2014 | Journal of Palaeogeography2014,3,2: | 15 |
| 17 | Jurassic sedimentary features and tectonic settings of southeastern China显示文摘Two types of the Jurassic basins are distinguished in SE China based on their geodynamic features: the Late Triassic-Early Jurassic post-orogenic basins and the Middle Jurassic intra-continental extensional basins. The Lower Jurassic sequence shows a change from coarseto fine-grained accumulation, suggesting a gradually deepening depositional environment from river to shore-lake and to deep-water lake. In contrast, the Middle Jurassic accumulation was changed from claystone to conglomerate along the coastal provinces in SE China, indicative of an initial crustal uplift. The Wuyi Mountains have been a paleogeograghic separating zone since the Middle Jurassic. The Late Jurassic strata are absent in most areas of SE China. A large-scale bimodal intra-continental rift-type volcanism occurred during the Middle Jurassic along a 40-60 km wide and 200 km long area in western Fujian and southern Jiangxi provinces, which is most likely the strongest volcanism in SE China since the Cambrian. The SHRIMP zircon U-Pb analyses on the rhyolite from the Dongkeng basin in the southern Jiangxi area yield a concord U-Pb age of 160±0.5 Ma, providing an upper age limit for the bimodal volcanic eruption. The analyses of the basin features indicate a change of the depositional environment during the interval from Middle Triassic to Late Triassic from a shallow-sea to an intra-continent in SE China in response to the strong collision between the Yangtze and North China Blocks. Sedimentary structures record a southward direction of Early Jurassic paleo-currents, reflecting that their source areas were to the north side. We propose that the Wuyi region was uplifted as early as Middle Jurassic, followed by a wide E-W-trending extended depression and bimodal volcanism in the western foot of the Wuyi Mountains. Presumably the uplift of the Wuyi domain changed the Middle Jurassic paleo geographic outline and formed the transformational tectonic regime from compression to extension as a tectonic response to the Pacific plate subduction. | SHU LiangShu WANG Yan SHA JinGeng JIANG ShaoYong YU JinHai WANG YanBin | 2009 | Science China Earth Sciences2009,52,12: | 15 |
| 18 | Crustal thicknesses and Poisson's ratios beneath the Chuxiong-Simao Basin in the Southeast Margin of the Tibetan Plateau显示文摘In the Southeast Margin of the Tibetan Plateau, low-velocity sedimentary layers that would significantly affect the accuracy of the H-κ stacking of receiver functions are widely distributed.In this study, we use teleseismic waveform data of 475 events from 97 temporary broadband seismometers deployed by ChinArray Phase I to obtain crustal thicknesses and Poisson's ratios within the Chuxiong-Simao Basin and adjacent area, employing an improved method in which the receiver functions are processed through a resonance-removal filter, and the H-κ stacking is time-corrected.Results show that the crustal thickness ranges from 30 to 55 km in the study area, reaching its thickest value in the northwest and thinning toward southwest, southeast and northeast.The apparent variation of crustal thickness around the Red River Fault supports the view of southeastern escape of the Tibetan Plateau.Relatively thin crustal thickness in the zone between Chuxiong City and the Red River Fault indicates possible uplift of mantle in this area.The positive correlation between crustal thickness and Poisson's ratio is likely to be related to lower crust thickening.Comparison of results obtained from different methods shows that the improved method used in our study can effectively remove the reverberation effect of sedimentary layers. | ZiQi Zhang Yuan Gao | 2019 | Earth and Planetary Physics2019,3,1: | 15 |
| 19 | Magnetic properties of sediments from the Pearl River Delta,South China:Paleoenvironmental implications显示文摘Magnetic parameters and their environmental implications of sediments in a core (PD) from the Pearl River Delta, South China, indicate that ferrimagnetic minerals with low coercivity, such as magnetite, dominate the magnetic properties although small amounts of Fe-sulphides occur. The fraction of Fe-sulphides increases and becomes the dominant minerals determining the magnetic characteristics in grey-black organic-rich clay horizons, indicating an anoxic, sulphate-reducing swamp environment resulting from a marine regression. In the 'Huaban clay' , hard magnetic minerals, such as hematite and goethite, largely control the magnetic properties of the sediments and imply a long period of exposure and weathering. Where magnetite is the main magnetic mineral, its fraction and grain size determine properties such as magnetic susceptibility (κ ) and saturation isothermal remanent magnetization (SIRM). Ratios of SIRM/κ and χarm/SIRM reflect changes in sea level with high SIRM/κ and χarm/SIRM correlating with a smaller magnetic mineral grain size and rising sea level. Based on downcore variations of these environmental magnetic parameters along with sediment characteristics and microfauna, the sedimentary environment of the Pearl River Delta area can be divided into two main cycles of transgression and regression during the late Pleistocene and Holocene with more sub-cycles of sea level fluctuation during each transgression. | Rodney GRAPES | 2008 | Science China Earth Sciences2008,51,1: | 13 |
| 20 | Relations between sedimentary sequence and paleoclimatic changes during last 200 ka in the southern South China Sea显示文摘Core NS-93-5 was taken from the mild slope terrace of the southern South China Sea (SCS), which has preserved the steadiness depositional record of the normal marine environment since late Quaternary. Sedimentary sequence and oxygen isotopic stratigraphy of high resolution in the near 200 ka of the southern SCS has been established. By the comparative analysis with GISP2’s ice core, the depositional record of D/O’s events 1-21 and Heinrich’s events H1-H6 in the southern SCS that reflected the quick climate change in short time scale since the last interglacial stage is revealed, which indicates that in the last 200 ka in the southern SCS and the Arctic area there was tele-connection of paleoclimate and the unstability of the Western Pacific Warm Pool. This note shows that the sedimentary layers order of this sea area classified by color identification and by oxygen isotope stratum has the very good corresponding relation. The color feature of sediment changes along with the climate and the former | Muhong Chen Xia Tu Fan Zheng Wen Yan Xianzan Tang Jun Lu Baogui Wang Miao’an Lu | 2000 | Chinese Science Bulletin2000,45,14: | 12 |