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Detrital Composition of Lower-Middle Jurassic Sandstones from Huangshi,Hubei:Implication for Provenance Types and Geotectonics 被引量:2
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作者 杨江海 杜远生 +1 位作者 覃永军 白雪峰 《Journal of Earth Science》 SCIE CAS CSCD 2009年第5期784-796,共13页
The detrital modes of the sandstones from the south basin of Dabie(大别) orogenic belt during the Early-Middle Jurassic are complex due to multiple supplying.Detrital compositions of medium-coarse sandstones from th... The detrital modes of the sandstones from the south basin of Dabie(大别) orogenic belt during the Early-Middle Jurassic are complex due to multiple supplying.Detrital compositions of medium-coarse sandstones from the Lower-Middle Jurassic,Huangshi(黄石),show three main provenances:recycled ororgen,volcanic arc(arc orogen),and continental block on the bases of the Dickinson discriminating diagrams of modal composition and analysis of sandstone petrofacies.Combined with sparse published paleocurrent data,geotectonic setting of the study area,and the unpublished detrital zircon age data,the positions of the main provenances are inferred as follows:coastal orogenic belt(COB) in the East China provided detritus as the recycled orogen provenance;Dabie orogenic belt(DOB) to the north was the source of volcanic arc(arc orogen) materials;and the continental block clasts were likely from the uplift of the Yangtze basement(UYB)(Jiangnan(江南) uplift).Six sedimentary cycles are recognized in the studied section,one in Wuchang(武昌) Formation,and five in Huajiahu(花家湖) Formation.During the deposition,the three main provenances play different roles.The quantitative petrofacies analysis revealed distinct changes of the effect from each source,that is,61.9%(Cycle Ⅰ)→54.5%(Cycle Ⅲ)→50%(Cycle Ⅳ)→57.9%(Cycle Ⅴ)→14.3%(Cycle Ⅵ),14.3%(Cycle Ⅰ)→21.2%( Cycle Ⅲ)→40%(Cycle Ⅳ)→36.8%(Cycle Ⅴ)→14.3%(Cycle Ⅵ),and 23.8%(Cycle Ⅰ)→24.2%(Cycle Ⅲ)→10%(Cycle Ⅳ)→5.3%(Cycle Ⅴ)→71.4%(Cycle Ⅵ) from COB,DOB,and UYB,respectively.The results show that(1) COB behaved in considerable activation during the EarlyJurassic but weakened in the Middle Jurassic;(2) the vigorous tectonic uplift of DOB initiated in Middle Jurassic;and(3) UYB was in stabilization basically from the Early to Middle Jurassic. 展开更多
关键词 Dabie orogenic belt lower-middle jurassic provenance analysis geotec-tonics.
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Hydrocarbon Generation Characteristics of Coal-measure Source Rocks and their Contribution to Natural Gas:A Case Study of Middle and Lower Jurassic Targets from the Southern Junggar Basin Margin 被引量:1
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作者 YU Miao GAO Gang +6 位作者 LIU Miao MA Wanyun TIAN Anqi FAN Keting GUO Liulinbo HE Dan ZHANG Youjin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第5期1270-1284,共15页
In order to study the hydrocarbon generation(HCGE)characteristics of coal-bearing basins,the coal-measure source rocks of the Middle Jurassic-Lower Jurassic(MLJ)of the piedmont thrust belt in the southern margin of th... In order to study the hydrocarbon generation(HCGE)characteristics of coal-bearing basins,the coal-measure source rocks of the Middle Jurassic-Lower Jurassic(MLJ)of the piedmont thrust belt in the southern margin of the Junggar Basin in Northwest China are taken as research objects.More than 60 MLJ samples were collected from outcrops and wells.Total organic carbon(TOC),rock pyrolysis(Rock-Eval),organic petrological,vitrinite reflectance(%Ro),and hydrous pyrolysis were performed to analyze the relevant samples.The pyrolysis gases and liquid products were measured,and then the chemical composition,as well as carbon isotopes of the gases,were analyzed.The results indicate that the MLJ source rocks have the capacity for large-scale gas generation.In addition,for coal-measure source rocks,the heavier the carbon isotope of kerogen(δ^(13)C_(kerogen)),the lower the liquid hydrocarbon and hydrocarbon gas yield,and the easier it is to produce non-hydrocarbon gas.It is worth noting that when theδ^(13)C_(kerogen)in organic matter(OM)is relatively heavier,the fractionation of its products may become weaker in the evolutionary process.The vital contribution of the MLJ source rock to natural gas resources in the study area was further confirmed by comparing it with the Jurassic source gas. 展开更多
关键词 upstream natural resources/energy coal-bearing basins source rock hydrous pyrolysis carbon isotope jurassic Xinjiang province
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High-resolution CT-scan data reveals the tooth replacement pattern of the Late Jurassic tyrannosauroid Guanlong wucaii (Dinosauria, Theropoda)
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作者 KE Yi-Hui PEI Rui XU Xing 《古脊椎动物学报(中英文)》 CSCD 北大核心 2024年第3期225-244,共20页
The Tyrannosauridae,which is characterized by specialized pachydont dentition and putative bone-cracking predatory strategies,is one of the most extensively studied theropod lineages.Although tooth replacement pattern... The Tyrannosauridae,which is characterized by specialized pachydont dentition and putative bone-cracking predatory strategies,is one of the most extensively studied theropod lineages.Although tooth replacement patterns,crucial for understanding feeding behaviors,have been thoroughly studied in this group,studies on non-tyrannosaurid tyrannosauroids are relatively scarce.This study utilizes high-resolution CT data to investigate the tooth replacement pattern in two specimens of Guanlong wucaii,a Late Jurassic tyrannosauroid,and provides insights into the evolution of tooth replacement across Tyrannosauroidea.Second-generation replacement teeth,a rarity observed mainly in giant predatory theropods(e.g.some tyrannosaurids),were detected in the dentary dentition of the juvenile Guanlong.Zahnreihen reconstructions display a consistent cephalad alternating tooth replacement pattern in the maxilla and the dentary of both of the examined individuals,with Z-spacing values exceeding 2.0.As Guanlong grows,the Z-spacing value in the maxillary dentition increases,resembling the ontogenetic changes documented in the Tyrannosauridae.Additionally,like Tarbosaurus,Guanlong also displays a discontinuity between the tooth replacement waves at the premaxilla-maxilla boundary.This study thus demonstrates that some tyrannosaurid-like tooth replacement patterns were acquired before the origin of the Tyrannosauridae. 展开更多
关键词 Late jurassic Tyrannosauroidea tooth replacement 3D reconstruction
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The Upper Jurassic sediments,Marib-Shabwa Basin,Yemen:Lithofacies aspects and sequence stratigraphic analysis
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作者 Mohammed Albaroot Mohamed M.Elhossainy +2 位作者 Nabil M.Al-Areeq Emad A.Abdullah Abdelhamid M.Salman 《Energy Geoscience》 EI 2024年第1期342-357,共16页
The present study is devoted to understanding the evolution of the Upper Jurassic Sab'atayn Formation in the Marib-Shabwa Basin,Yemen,through a sequence stratigraphic analysis based on integrating datasets of sedi... The present study is devoted to understanding the evolution of the Upper Jurassic Sab'atayn Formation in the Marib-Shabwa Basin,Yemen,through a sequence stratigraphic analysis based on integrating datasets of sedimentology,seismic sections,and well logs.The Sab'atayn Formation(Tithonian age)is represented by a series of clastic and evaporites that were deposited under fluvio-deltaic to prodeltaic settings.It is divided into four members including Yah(at the base),upwards to Seen,Alif,and Safir at the top.Two third-order depositional sequences were determined for the Tithonian succession which were separated by three sequence boundaries.These sequences were classified into their systems tracts signifying several sedimentation patterns of progradational,aggradational,and retrogradational parasequence sets.The first depositional sequence corresponds to the early-middle Tithonian Yah and Seen units that can be classified into lowstand,transgressive,and highstand systems tracts.The second sequence comprises the late Tithonian Alif unit that can be subdivided into transgressive and highstand systems tracts.The sandy deposits of the Alif Member(highstand deposits)represent the most productive hydrocarbon reservoir in the basin.The Upper Jurassic sediments in the study area were resulted from a combination of eustatic and tectonic effects. 展开更多
关键词 Sequence stratigraphy Sandstone reservoir Well logs Upper jurassic Marib-Shabwa Basin Yemen
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Whole petroleum system in Jurassic coal measures of Taibei Sag in Tuha Basin,NW China
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作者 ZHI Dongming LI Jianzhong +6 位作者 YANG Fan CHEN Xuan WU Chao WANG Bo ZHANG Hua HU Jun JIN Jikun 《Petroleum Exploration and Development》 SCIE 2024年第3期519-534,共16页
Based on the latest results of near-source exploration in the Middle and Lower Jurassic of the Tuha Basin,a new understanding of the source rocks,reservoir conditions,and source-reservoir-cap rock combinations of the ... Based on the latest results of near-source exploration in the Middle and Lower Jurassic of the Tuha Basin,a new understanding of the source rocks,reservoir conditions,and source-reservoir-cap rock combinations of the Jurassic Shuixigou Group in the Taibei Sag is established using the concept of the whole petroleum system,and the coal-measure whole petroleum system is analyzed thoroughly.The results are obtained in three aspects.First,the coal-measure source rocks of the Badaowan Formation and Xishanyao Formation and the argillaceous source rocks of the Sangonghe Formation in the Shuixigou Group exhibit the characteristics of long-term hydrocarbon generation,multiple hydrocarbon generation peaks,and simultaneous oil and gas generation,providing sufficient oil and gas sources for the whole petroleum system in the Jurassic coal-bearing basin.Second,multi-phase shallow braided river delta–shallow lacustrine deposits contribute multiple types of reservoirs,e.g.sandstone,tight sandstone,shale and coal rock,in slope and depression areas,providing effective storage space for the petroleum reservoir formation in coal-measure strata.Third,three phases of hydrocarbon charging and structural evolution,as well as effective configuration of multiple types of reservoirs,result in the sequential accumulation of conventional-unconventional hydrocarbons.From high structural positions to depression,there are conventional structural and structural-lithological reservoirs far from the source,low-saturation structural-lithological reservoirs near the source,and tight sandstone gas,coal rock gas and shale oil accumulations within the source.Typically,the tight sandstone gas and coal rock gas are the key options for further exploration,and the shale oil and gas in the depression area is worth of more attention.The new understanding of the whole petroleum system in the coal measures could further enrich and improve the geological theory of the whole petroleum system,and provide new ideas for the overall exploration of oil and gas resources in the Tuha Basin. 展开更多
关键词 Tuha Basin Taibei Sag Middle and Lower jurassic whole petroleum system coal measure tight oil and gas coal rock gas shale oil
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Two Jurassic Mammaliaforms from China Shed Light on Mammalian Evolution
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《Bulletin of the Chinese Academy of Sciences》 2024年第2期126-128,共3页
Mammaliaforms are extinct and extant organisms that are closely related to mammals.Studying mammaliaforms helps scientists understand the evolutionary processes that led to various mammalian features.In two consecutiv... Mammaliaforms are extinct and extant organisms that are closely related to mammals.Studying mammaliaforms helps scientists understand the evolutionary processes that led to various mammalian features.In two consecutive studies in Nature,Dr.MAO Fangyuan and Dr.ZHANG Chi from the Institute of Vertebrate Paleontology and Paleoanthropology(IVPP)of the Chinese Academy of Sciences(CAS),together with colleagues from Australia and the United States. 展开更多
关键词 MAMMALIA MAMMALIAN jurassic
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Hydrocarbon Potential of the Triassic-Jurassic Sediments in Southeast Sulawesi, Indonesia, Based on Lithofacies and Geochemical Analysis
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作者 Muhammad Sulhuzair Burhanuddin Shun Chiyonobu +3 位作者 Takuto Ando Anggi Yusriani Ratna Husain Suryawan Asfar 《Open Journal of Geology》 CAS 2024年第8期723-745,共23页
Triassic-Jurassic carbonates widely distributed in Eastern Indonesia are believed as oils source rock. The Mesozoic Tokala Formation exhibit source rock potential, as evidenced by high contents of organic matter. Rece... Triassic-Jurassic carbonates widely distributed in Eastern Indonesia are believed as oils source rock. The Mesozoic Tokala Formation exhibit source rock potential, as evidenced by high contents of organic matter. Recent exploration has been conducted in southeastern Sulawesi, targeting the Mesozoic intervals. Therefore, in this study, we attempted to determine source rock potential of Tokala Formation outcropped in southeastern Sulawesi area and its capability to generate hydrocarbon. Five distinct lithofacies were delineated, emphasizing lithological and mineralogical features: foraminifera wackestone (FW), lime mudstone (LM), massive bioturbated calcareous-argillaceous shale (MBCAS), weakly laminated argillaceous-calcareous shale (WLACS), and strongly laminated calcareous-argillaceous shale (SLCAS). Subsequent analyses showed that carbonate-rich samples (FW and LM facies, >50% CaO) had poor source rock potential. Conversely, shale facies with moderate carbonate content (WLACS, MBCAS, and SLCAS, 15% - 50% CaO) had good to excellent source rock characteristics, qualifying them as preferable source rock. In addition, levels of SiO2 and Al2O3 should not be neglected, as these constituents play important roles in clay mineral adsorption. Laminated shale facies with moderate CaO content tended to be more promising as source rock than bioturbated facies. The shale facies of Tokala Formation indicate prospective source rock horizon. 展开更多
关键词 Source Rock Triassic-jurassic Source Rock Lithofacies Southeastern Sulawesi Tokala Formation
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A New Genus of Mesoserphidae (Hymenoptera: Proctotrupoidea) from the Upper Jurassic of Northeast China 被引量:5
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作者 张海春 张俊峰 《Entomotaxonomia》 CSCD 2000年第4期279-282,共4页
The genus Beipiaoserphus gen. nov. is established and referred to Mesoserphidae with Beipiaoserphus elegans sp. nov. as its type species. The type specimens were collected from the lower part of the Upper Jura... The genus Beipiaoserphus gen. nov. is established and referred to Mesoserphidae with Beipiaoserphus elegans sp. nov. as its type species. The type specimens were collected from the lower part of the Upper Jurassic Yixian Formation at Huangbanjigou Village near Shangyuan Town, Beipiao, Liaoning Province, China and are housed at Nanjing Institute of Geology and Palaeontology, Academia Sinica, Nanjing. 展开更多
关键词 HYMENOPTERA Mesoserphidae new genus new species Upper jurassic Yixian Formation Northeast ChiH
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A NEW SPECIES OF OMEISAURUS FROM THE MIDDLE JURASSIC OF ZIGONG,SICHUAN 被引量:4
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作者 江山 李飞 +1 位作者 彭光照 叶勇 《古脊椎动物学报》 CSCD 北大核心 2011年第2期185-194,共10页
记述了产自四川自贡大山铺中侏罗世峨眉龙属一新种——焦氏峨眉龙(Omeisaurusjiaoisp.nov.)。新种为大型蜥脚类恐龙,以如下特征区别于其他蜥脚类:前、中部背椎为典型的后凹型,后部背椎为双平型,背椎神经棘呈高大棒状,不分叉;尾... 记述了产自四川自贡大山铺中侏罗世峨眉龙属一新种——焦氏峨眉龙(Omeisaurusjiaoisp.nov.)。新种为大型蜥脚类恐龙,以如下特征区别于其他蜥脚类:前、中部背椎为典型的后凹型,后部背椎为双平型,背椎神经棘呈高大棒状,不分叉;尾椎为弱双凹型,第一尾椎不具扇形尾肋;第一脉弧短小且与第一尾椎关联;锁骨长大;肱骨和股骨细长而圆实;肱骨与股骨长度之比为0.83,尺骨与肱骨长度之比为0.72,胫骨与股骨长度之比为0.63。 展开更多
关键词 四川自贡大山铺 中侏罗世 蜥脚类 峨眉龙
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Middle Jurassic Sporo-pollen Assemblages in Northern Turpan Depression, Xinjiang, Northwest China 被引量:2
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作者 尹凤娟 张子福 《Acta Botanica Sinica》 CSCD 2002年第4期488-495,共8页
Eighty-one species of fossil spores and pollen assigned to 52 genera are found from the Middle Jurassic Xishanyao, Sanjianfang and Qiketai Formations of boreholes Le 1, Mi 1, Shan 1 and Dun 1 in the northern Turpan De... Eighty-one species of fossil spores and pollen assigned to 52 genera are found from the Middle Jurassic Xishanyao, Sanjianfang and Qiketai Formations of boreholes Le 1, Mi 1, Shan 1 and Dun 1 in the northern Turpan Depression, Xinjiang, northwest China. Three assemblages have been proposed as: Cyathidites-Psophosphaera-Cycadopites assemblage, Cyathidites-Quadraceculina-Classopollis assemblage and Cyathidites-Callialasporites-Classopollis assemblage obtained from the Xishanyao Formation, the Sanjianfang Formation and Qiketai Formation respectively. Based on the sporo-pollen assemblage features and con-elation, their geological ages are regarded as of Middle Jurassic, probably Aalenian to Bathonian. The results of the study indicate that the vegetation of early Middle Jurassic in this region consisted mainly of Gymnospermae of Ginkgoaceae of Cycadales, Podocarpaceae, Pinaceae and Pteridophyta of Cyatheacene, Osmundaceae, Lycopodiaceae and Dicksoniaceae, etc. They reflect a warm-moist subtropic climate. To the middle-late Middle Jurassic, Cheirolepidaceae was dominant in the vegetation, which indicates that the climate was in the trend of becoming dry. 展开更多
关键词 spore and pollen climate Middle jurassic northwest China
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Coal petrology and genesis of Jurassic coal in the Ordos Basin,China 被引量:4
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作者 Weihua Ao Wenhui Huang +7 位作者 Chengmin Weng Xiuling Xiao Dameng Liu Xiuyi Tang Ping Chen Zhigen Zhao Huan Wan Robert B.Finkelman 《Geoscience Frontiers》 CAS 2012年第1期85-95,共11页
Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high... Multiple sets of thick coal beds characterized by simple structure and shallow burial depth were developed in the Early and Middle Jurassic strata of the Ordos Basin, northwestern China. The huge reserves of this high quality coal have a high commercial value. We studied the coal's petrologic characteristics and its maceral distribution to determine the maceral's contribution to generation of oil and gas. The results show that the Jurassic coals in the Ordos Basin have special petrological features because of the Basin's unique depo- sitional environment which was mainly a series of high-stand swamps in the upper fluvial system. These petro- graphic features are a result of the development of typical inland lakes where some sand bodies were formed by migrating rivers. After burial, the peat continued to undergo oxidizing conditions, this process generated extensive higher inertinite contents in the coals and the vitrinite components were altered to semi-vitrinite. The macroscopic petrographic types of these Jurassic coals are mainly semi-dull coal, dull coal, semilustrous and lustrous coal. The proportions of semi-dull coal and dull coal are higher in the basin margins, especially in the area near the northern margin. The numbers of semilustrous and lustrous coals increase southwards and towards the central basin. This situation indicates that different coal-forming swamp environments have major controlling effects on the coal components. Another observation is that in the Ordos' coal sequences, especially in the lower part, some sandstone beds are thick, up to 20 m with a coarse grain size. The higher fusinite content in the macerals accompanies a higher semi-vitrinite content with more complete and regular plant cell structure. The fusinite structure is clear and well preserved. After burial, the lithology of the roof and floor rocks can continue to affect the evolution of coal petrology. The sand bodies in the roof and floor exhibit good physical conditions so that pore water can maintain a long-term state of oxidation, circulation and connection to the coal. So coal components remain in an oxidation environment for a long time. Conversely, in the basin center, lacustrine facies developed and peat was rapidly covered by mudstone after burial and subsequent coal beds rapidly entered a reducing environment. As a result, abundant gelatification occurred and the vitrinite content increased. E^inite often accumulated in a specific position in the coal bed. Although the average exinite content is not high on the whole, it does significantly contribute to the total hydrocarbon generation. The exinite content has been underestimated, especially the amorphous bituminous fluid and its importance is emphasized here. The reason is that the fluid flows easily into fusinite which has strong rigidity, or flows into some fissures, where it is commonly neglected. 展开更多
关键词 lower-middle jurassicCoal-formingenvironment Coal maceral Ordos Basin
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Xingxueanthus: An Enigmatic Jurassic Seed Plant and Its Implications for the Origin of Angiospermy 被引量:13
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作者 WANG Xin WANG Shijun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2010年第1期47-55,共9页
The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non-convincing or misdated. The applications o... The origin of angiosperms has been tantalizing botanists for centuries. Despite the efforts of palaeobotanists, most of the pre-Cretaceous angiosperms are regarded either non-convincing or misdated. The applications of SEM and LM (light microscope) enable us to recognize a coalified fossil plant, Xingxueanthus sinensis gen. et sp. nov., from the Haifanggou Formation (Middle Jurassic, 〉160 Ma) in western Liaoning, China. Xingxueanthus is an "inflorescence" with more than 20 female units spirally arranged. Each female unit is situated in the axii of a bract. The female unit is composed of an ovule-container and a style-like projection at the top. There is a vertical column bearing several ovules in the ovule-container. The general morphology and the internal structure of Xingxueanthus distinguish itself from any known fossil and extant gymnosperms, and its structures are more comparable to those of angiosperms. Xingxueanthus, if taken as a gymnosperm, would represent a new class, demonstrate an evolutionarily advanced status of ovule-protection in gymnosperms never seen before, and provide new insights into the origin of angiospermy. Alternatively, if taken as an angiosperm, together with Schmeissneria, it would increase the diversity of Jurassic angiosperms, which has been underestimated for a long time, and suggest a much earlier origin of angiospermy than currently accepted. 展开更多
关键词 ANGIOSPERM FLOWER ORIGIN LIAONING jurassic
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Quantitative Analysis of Paleoatmospheric CO2 Level Based on Stomatal Characters of Fossil Ginkgo from Jurassic to Cretaceous in China 被引量:22
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作者 SUN Bainian XIAO Liang +4 位作者 XIE Sanping DENG Shenghui WANG Yongdong JIA Hui Susan Tumer 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第6期931-939,共9页
A better theoretical and practical understanding of the linkage between paleo-CO2 and climate during geological history is important to enhance the sustainable development of modern human society. Development in plant... A better theoretical and practical understanding of the linkage between paleo-CO2 and climate during geological history is important to enhance the sustainable development of modern human society. Development in plant physiology since the 1980s has led to the realization that fossil plants can serve as a proxy for paleoatmosphere and paleobiosphere. As a relict gymnosperm with evolutionary stasis, Ginkgo is well suited for paleoenvironmental reconstruction. This paper analyzes fossil Ginkgo species from integrated strata in the north of China using anatomic data of plant physiology. Using stomatal parameters, a trend for the paleo-CO2 level during the Early-Middle Jurassic and the Early Cretaceous was obtained, which is consistent with the estimates by GEOCARB. The trend is also similar to that of Mean Global Surface Temperature in geological time. Compared with three other atmospheric CO2 concentration parameters, the trend of paleo-CO2 level based on the stomatal parameter of the fossil Ginkgo specimens from three contiguous strata is more exact. 展开更多
关键词 jurassic CRETACEOUS fossil Ginkgo stomatal parameter paleoatmospheric CO2
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New Jurassic Fossil True Bugs of the Pachymeridiidae(Hemiptera:Pentatomomorpha)from Northeast China 被引量:9
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作者 YAO Yunzhi CAI Wanzhi REN Dong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第1期35-47,共13页
Four new fossil genera and species of true bugs from the family Pachymeridiidae, Beipiaocoris multifurcus, Bellicoris mirabilis, Nitoculus regiUus, and Viriosinervis stolidus, are described. New specimens were collect... Four new fossil genera and species of true bugs from the family Pachymeridiidae, Beipiaocoris multifurcus, Bellicoris mirabilis, Nitoculus regiUus, and Viriosinervis stolidus, are described. New specimens were collected from the Middle and Upper Jurassic non-marine sedimentary strata from the Jiulongshan and Yixian Formations of northeast China. The species Karatavocoris asiatica Becker-Migdisova, 1963, which was considered to be a member of the family Coreidae is transferred to the Pachymeridiidae. A new map of all known and newly discovered fossil pachymeridiid localities is given. The diagnosis of the family is modified. 展开更多
关键词 HEMIPTERA Pachymeridiidae new genera FOSSIL Late jurassic Yixian Formation Middle jurassic Jiulongshan Formation China
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Jurassic Tectonics of North China:A Synthetic View 被引量:32
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作者 ZHANG Yueqiao DONG Shuwen +1 位作者 ZHAO Yue ZHANG Tian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2008年第2期310-326,共17页
This paper gives a synthetic view on the Jurassic tectonics of North China, with an attempt to propose a framework for the stepwise tectonic evolution history. Jurassic sedimentation, deformation and magmatism in Nort... This paper gives a synthetic view on the Jurassic tectonics of North China, with an attempt to propose a framework for the stepwise tectonic evolution history. Jurassic sedimentation, deformation and magmatism in North China have been divided into three stages. The earliest Jurassic is marked by a period of magmatism quiescence (in 205-190 Ma) and regional uplift, which are considered to be the continuation of the “Indosinian movement” characterized by continent-continent collision between the North and South China blocks. The Early to Middle Jurassic (in 190-170 Ma) was predominated by weak lithospheric extension expressed by mantle-derived plutonism and volcanism along the Yanshan belt and alongside the Tan-Lu fault zone, normal faulting and graben formation along the Yinshan- Yanshan tectonic belt, depression and resuming of coal-bearing sedimentation in vast regions of the North China block (NCB). The Middle to Late Jurassic stage started at 165y.5 Ma and ended up before 136 Ma; it was dominated by intensive intraplate deformation resulting from multi-directional compressions. Two major deformation events have been identified. One is marked by stratigraphic unconformity beneath the thick Upper Jurassic molasic series in the foreland zones of the western Ordos thrust-fold belt and along the Yinshan-Yanshan belt; it was predated 160 Ma. The other one is indicated by stratigraphic unconformity at the base of the Lower Cretaceous and predated 135 Ma. During this last stage, two latitudinal tectonic belts, the Yinshan-Yanshan belt in the north and the Qinling-Dabie belt in the south, and the western margin of the Ordos basin were all activated by thrusting; the NCB itself was deformed by the NE to NNE-trending structural system involving thrusting, associated folding and sinistral strike-slip faulting, which were spatially partitioned. Foliated S-type granitic plutons aged 160-150 Ma were massively emplaced in the Jiao-Liao massif east of the Tan-Lu fault zone and indicate important crustal thickening in this part of the NCB. The Jurassic deformation patterns, different tectonic systems and multi-directional contractions in North China recorded far-field effects of synchronous convergences, toward the East Asian continent, of three different plates, the Siberian plate in the north, the paleo-Pacific oceanic plate in the east and the Lhasa block in the southwest. This Middle to Late Jurassic intraplate orogenesis and pervasive shortening deformation preceded lithospheric attenuation and thinning in East China, which most possibly started by the Early Cretaceous around 135 Ma. 展开更多
关键词 jurassic tectonics intraplate deformation North China multi-directional compression
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Radiometric Dating of Ignimbrite from Inner Mongolia Provides no Indication of a Post-Middle Jurassic Age for the Daohugou Beds 被引量:30
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作者 GAO Ke-Qin REN Dong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2006年第1期42-45,共4页
Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of... Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed. 展开更多
关键词 Daohugou beds Inner Mongolia Middle jurassic age dispute radlometric dating
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Middle Jurassic-early Cretaceous radiolarian assemblages of the western Yarlung Zangbo Suture Zone: Implications for the evolution of the Neo-Tethys 被引量:10
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作者 Hanting Zhong Jingen Dai +2 位作者 Chengshan Wang Yalin Li Yushuai Wei 《Geoscience Frontiers》 SCIE CAS CSCD 2017年第5期989-997,共9页
Cherts in the Zhongba melange of the western Yarlung Zangbo Suture Zone(YZSZ) contain well preserved radiolarian assemblages. These radiolarian assemblages indicate that the Zhongba melange has middle Jurassic-early C... Cherts in the Zhongba melange of the western Yarlung Zangbo Suture Zone(YZSZ) contain well preserved radiolarian assemblages. These radiolarian assemblages indicate that the Zhongba melange has middle Jurassic-early Cretaceous remnant, are coeval with those from the central and eastern parts of the YZSZ. Cherts from the Najiu area yield Aalenian to Aptian radiolarians, while cherts interbedded with siliceous mudstones from the Bielongjiala area yield Aptian radiolarians, indicating that terrigenousderived sediments were deposited during early Aptian. The above observations indicate that the entire YZSZ have a similar geochronological framework and thus they underwent similar geological evolution:(1) during the Jurassic, the Neo-Tethys was a wide ocean with pelagic sediments distal from continents;(2) during the Cretaceous(around 130-120 Ma), the Neo-Tethys started to subduct along the southern margin of the Lhasa block, and terrigenous-derived siliceous mudstone began deposition. 展开更多
关键词 RADIOLARIAN chert jurassic Cretaceous Yarlung Zangbo SUTURE Zone
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Jurassic Intra-plate Basaltic Magmatism in Southeast China:Evidence from Geological and Geochemical Characteristics of the Chebu Gabbroite in Southern Jiangxi Province 被引量:12
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作者 XIE Guiqing MAO Jingwen +4 位作者 HU Ruizhong LI Ruiling JIANG Guohao CAO Jinjian ZHAO Junhong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第5期662-672,共11页
Geochemical and isotopic investigations have been carded out on the Chebu gabbroite in southern Jiangxi Province, southeast China and these results are compared with gabbro bodies along the coast of Fujian Province in... Geochemical and isotopic investigations have been carded out on the Chebu gabbroite in southern Jiangxi Province, southeast China and these results are compared with gabbro bodies along the coast of Fujian Province in order to understand their magma sources and tectonic implications. The Chebu intrusion formed at the beginning of the Middle Jurassic (172~4.3 Ma). These rocks are Ti-rich and Al-poor in major elements, characterized by strong enrichment in large-ion lithophile elements (LILE) and moderate enrichment in high field strength elements (HFSE) and light rare-earth elements CLREE), without pronounced Nb or Ta anomalies. Age-correlated Sr-Nd isotope ratios show moderately high ranges of (^87Sr/^86Sr)i from 0.7065 to 0.7086 and 0.5124 to 0.5125 of (^143Nd/^144Nd)i. The geochemical characteristics of the Chebu gabbroite suggest that it is notably different from island-arc basalt and similar to intra-plate basaltic rocks. By combining interpretations of its geological and geochemical characteristics and the regional geological development history, the Chebu gabbroitic intrusion is thought to be the product of asthenosphere upwelling and rapid lithosphere extension during a transition of tectonic systems in southeast China. The tectonic environment and source characteristics of the intrusion are different from Cretaceous gabbro bodies along the coast of Fujian Province, The former formed in a tectonic environment of rapid intra-plate lithospheric extension and the source characteristics were of a weakly enriched primitive mantle, whereas the latter originated mainly in a volcanic-magmatic arc extensional tectonic environment and the nature of the source was an enriched mantle with more subduct subducted components. 展开更多
关键词 gabbroite geochemical characteristics geodynamics setting jurassic Jiangxi southeast China
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A New Ceratopsian from the Upper Jurassic Houcheng Formation of Hebei, China 被引量:9
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作者 ZHAO Xijin CHENG Zhengwu +1 位作者 XU Xing Peter J. MAKOVICKY 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2006年第4期467-473,共7页
A new ceratopsian taxon Xuanhuaceratops niei gen. et sp. nov. is erected based on four fragmentary specimens collected from the Late Jurassic Houcheng Formation, Hebei Province, China. Xuanhuaceratops shares a number ... A new ceratopsian taxon Xuanhuaceratops niei gen. et sp. nov. is erected based on four fragmentary specimens collected from the Late Jurassic Houcheng Formation, Hebei Province, China. Xuanhuaceratops shares a number of derived features with, and is closely related to, another probable Late Juarassic ceratopsian Chaoyangsaurus youngi, from which it differs in only possessing a single premaxlllary tooth as well as in details of quadrate and scapular morphology. We hypothesize that these two taxa represent a primitive lineage of Ceratopsia that is basal to the psittacosauridneoceratopsian diversity, and propose the name Chaoyangsauridae for it. 展开更多
关键词 Houcheng Formation jurassic Hebei Chaoyangsauridae CERATOPSIA
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Early Jurassic Soft-Sediment Deformation Interpreted as Seismites in the Wuqia Pull-Apart Basin and the Strike-Slip Talas-Ferghana Fault, Xinjiang, China 被引量:15
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作者 QIAO Xiufu GUO Xianpu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2013年第3期730-737,共8页
The early Jurassic soft-sediment deformation occurring within lacustrine sandstone is distributed mainly in the Wuqia region of SW Tianshan Mountains, Xinjiang, western China. Triggered by earthquakes, such deformatio... The early Jurassic soft-sediment deformation occurring within lacustrine sandstone is distributed mainly in the Wuqia region of SW Tianshan Mountains, Xinjiang, western China. Triggered by earthquakes, such deformation was found to occur in three beds overlying the lower Jurassic Kangsu Formation. The main styles of deformation structures comprise load cast, ball-and- pillow, droplet, cusps, homogeneous layer, and liquefied unconformity. The deformation layers reflect a series of three strong earthquakes at the end of early Jurassic in the Wuqia region. The differences of deformation mechanisms undergone might represent the varying magnitudes of the earthquake events. During the early Jurassic, the Wuqia region was located in a pull-apart basin controlled by the significant Talas-Ferghana strike-slip fault in central Asia, which initiated the soft-sediment deformation induced by earthquakes. Our research suggests that the paleoseismic magnitudes could have ranged from Ms 6.5 to 7. 展开更多
关键词 Early jurassic seismicity load droplet liquefied unconformity Talas-Ferghana fault XINJIANG
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