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New material of Coniopteris simplex from the Middle Jurassic of the Ordos Basin,Inner Mongolia,china and implications on its spatio-temporal distribution and paleogeography

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Journal of Palaeogeography 2024年第2期13卷 199-211页

作者： Yun-Feng Li Chang-Lu Zhang Fei Liang Xiao Tan Fan-Hao Gong Chun-Lin Sun Tao Li Yu-Ling Na Research Center of Paleontology and Stratigraphy Jilin UniversityChangchun 130026Jilin ProvinceChina College of Earth Sciences Jilin UniversityChangchun 130061Jilin ProvinceChina College of Paleontology Shenyang Normal UniversityShenyang 110034Liaoning ProvinceChina Key Lab of Evolution of Past Life in NE Asia Ministry of Natural ResourcesShenyang Normal UniversityShenyang 110034Liaoning ProvinceChina Shenyang Center of geological survey China Geological SurveyShenyang 110034Liaoning ProvinceChina

Coniopteris simplex is a common component in many Jurassic ***,due to morphological variations in sterile fronds and incomplete preservation of reproductive organs,its classification has been controversial for a long ***,we present new material collected from the Middle Jurassic Yan’an Formation in the Ordos Basin,Inner *** new material reveals important morphological characters,including hemi-dimorphic fronds,two forms of sterile pinnae,short-stalked sori and sporangia on fertile fronds,annulus of sporangium composed of about 30 cells,in situ rounded triangular spores with protruded suture,and the lips of trilete laesura encircled by one or two rows of small *** on these observations,we emended the diagnosis of this common *** spatio-temporal distribution of Coniopteris simplex shows that the iconic species was restricted to the paleolatitudes ranging from 19.5°N to 48.9°N in the Northern Hemisphere during the Early—Late Jurassic,mainly distributed in the tropical to paratropical zones,and the paleolongitude ranging from 9.6°E to 129.3°E,which may be limited by the opening of the Viking Corridor and the splitting of the Central Atlantic Ocean.

关键词： Coniopteris simplex Yan'an Formation Middle Jurassic Inner Mongolia Paleogeography

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Ore Geology,H-O-C Isotopes and 40Ar-39Ar Dating of the Wutonggou Iron Deposit,Eastern Tianshan,NW china:Implications for the Source,Timing,and Genesis of Hydrothermal Mineralization in a Sedimentary Iron Deposit

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Journal of Earth Science 2024年第4期35卷 1170-1185页

作者： Chun-Long Wang Yi-Tian Wang State Key laboratory of geological Processes and Mineral Resources Collaborative Innovation Center for Exploration of Strategic Mineral ResourcesSchool of Earth ResourcesChina University of GeosciencesWuhan430074China MNR Key laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing100037China

The Wutonggou iron deposit is located in the well-known iron metallogenic belt in the eastern Tianshan,NW china,and has been regarded as a sedimentary iron *** hydrothermal overprinting could play indispensable roles in the formation of high-grade iron ores in sedimentary iron deposits,previous studies mainly focused on sedimentary-related iron mineralization,while the nature and contribution of hydrothermal fluids are poorly ***,an integrated study of ore geology,H-O-C isotopes and^(40)Ar-^(39)Ar dating,is conducted on the Wutonggou deposit,in order to reveal the features,source,and timing of hydrothermal *** studied deposit includes two mining sections namely the Jianshan and ***δ^(18)O values of early magnetite from the Jianshan section range from+3.0‰to+5.8‰that nearly consistent with classic magmatic magnetite,while increase to 6.3‰-8.0‰in the late *** from the two sections shows comparable H-O isotopic compositions and identical fractionation trends,and is plotted in or periphery to the primary magmatic water *** from the two sections are broadly similar in carbon and oxygen isotopic compositions,and siderite from the Wutonggou section is plotted in the same ***,comparable stable isotopic compositions and evolution trends indicate similar magmatic fluids contributed hydrothermal iron mineralization in the two mining ***,water-rock interactions of varying degrees generated distinct mineralization styles in the Jianshan and Wutonggou sections,and caused the isotopic fractionation in late *** extracted from a hydrothermal siderite ore yielded a^(40)Ar-^(39)Ar plateau age of 299.5±2.0 Ma,indicates the timing of hydrothermal iron mineralization is corresponding to the emplacement of vicinity *** together,the hydrothermal mineralization in the Wutonggou iron deposit was the product of remobilization and upgrading of early sedimentary iron ores,a

关键词： iron deposits H-O-C isotopes 40Ar-39Ar dating sedimentary iron deposits Wutonggou iron deposit eastern Tianshan

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Novel method for identifying the stages of discharge underwater based on impedance change characteristic

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Plasma Science and Technology 2024年第4期26卷 133-145页

作者：高崇康忠健龚大建张扬王玉芳孙一鸣 Department of New Energy China University of PetroleumQingdao 266580People’s Republic of China Shanghai Ruida Fengzhi Science and Technology Corporation Shanghai 201703People’s Republic of China china National Petroleum Group General Research Institute of Engineering and Technology Corporation Beijing 100029People’s Republic of China Oil and Gas Resource survey Center China Geological SurveyBeijing 100083People’s Republic of China

It is difficult to determine the discharge stages in a fixed time of repetitive discharge underwater due to the arc formation process being susceptible to external environmental influences. This paper proposes a novel underwater discharge stage identification method based on the Strong Tracking Filter(STF) and impedance change characteristics. The time-varying equivalent circuit model of the discharge underwater is established based on the plasma theory analysis of the impedance change characteristics and mechanism of the discharge process. The STF is used to reduce the randomness of the impedance of repeated discharges underwater, and then the universal identification resistance data is obtained. Based on the resistance variation characteristics of the discriminating resistance of the pre-breakdown, main, and oscillatory discharge stages, the threshold values for determining the discharge stage are obtained. These include the threshold values for the resistance variation rate(K) and the moment(t).Experimental and error analysis results demonstrate the efficacy of this innovative method in discharge stage determination, with a maximum mean square deviation of Scrless than 1.761.

关键词： discharge underwater discharge stage identification impedance characteristics strong tracking filter

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geological reservoir and resource potential(10^(13)m^(3))of gas hydrates in the South china Sea

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china Geology 2024年第3期7卷 422-444页

作者： Pi-bo Su Wei Wei Yun-bao Sun Yao-yao Lü Huai Cheng Wei-feng Han Wei Zhang Jin-qiang Liang National Engineering Research Center for Gas Hydrate Exploration and Development Guangzhou 511458China Sanya Institute of South china Sea Geology Guangzhou Marine Geological SurveySanya 572025China Central laboratory of geological Sciences Research Institute of Petroleum Exploration and DevelopmentLangfang 065007China Qingdao Institute of Marine Geology Qingdao 266237China laboratory for Marine Mineral Resources Qingdao Marine Science and Technology CenterQingdao 266237China

A detailed understanding of the distribution and potential of natural gas hydrate(NGHs)resources is crucial to fostering the industrialization of those resources in the South china Sea,where NGHs are *** this study,this study analyzed the applicability of resource evaluation methods,including the volumetric,genesis,and analogy methods,and estimated NGHs resource potential in the South china Sea by using scientific resource evaluation methods based on the factors controlling the geological accumulation and the reservoir characteristics of ***,this study compared the evaluation results of NGHs resource evaluations in representative worldwise sea areas via rational *** results of this study are as follows:(1)The gas hydrate accumulation in the South china Sea is characterized by multiple sources of gas supply,multi-channel migration,and extensive accumulation,which are significantly different from those of oil and gas and other unconventional resources.(2)The evaluation of gas hydrate resources in the South china Sea is a highly targeted,stratified,and multidisciplinary evaluation of geological resources under the framework of a multi-type gas hydrate resource evaluation system and focuses on the comprehensive utilization of multi-source heterogeneous data.(3)Global NGHs resources is n×10^(15)m^(3),while the NGHs resources in the South china Sea are estimated to be 10^(13)m^(3),which is comparable to the abundance of typical marine NGHs deposits in other parts of the *** the South china Sea,the NGHs resources have a broad prospect and provide a substantial resource base for production tests and industrialization of NGHs.

关键词： Reservoir characteristics Natural gas hydrates Gas migration Resource potential Resource evaluation methods Hierarchical evaluation system Volumetric method South china Sea Clean energy exploration engineering

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Delineating homogeneous domains of fractured rocks using topological manifolds and deep learning

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 2996-3013页

作者： Yongqiang Liu Jianping Chen Fujun Zhou Jiewei Zhan Wanglai Xu Jianhua Yan College of Construction Engineering Jilin UniversityChangchun130026China china Railway First survey and Design Institute Group Co. Ltd.Xi’an710043China College of geological Engineering and Geomatics Chang’an UniversityXi’an710054China

Determining homogeneous domains statistically is helpful for engineering geological modeling and rock mass stability *** this text,a technique that can integrate lithology,geotechnical and structural information is proposed to delineate homogeneous *** technique is then applied to a high and steep slope along a ***,geological and geotechnical domains were described based on lithology,faults,and shear ***,topological manifolds were used to eliminate the incompatibility between orientations and other parameters(*** length and roughness)so that the data concerning various properties of each discontinuity can be matched and characterized in the same Euclidean ***,the influence of implicit combined effect in between parameter sequences on the homogeneous domains could be *** learning technique was employed to quantify abstract features of the characterization images of discontinuity properties,and to assess the similarity of rock mass *** results show that the technique can effectively distinguish structural variations and outperform conventional *** can handle multisource engineering geological information and multiple discontinuity *** technique can also minimize the interference of human factors and delineate homogeneous domains based on orientations or multi-parameter with arbitrary distributions to satisfy different engineering requirements.

关键词： Homogeneous domain geological domain Geotechnical domain Structural domain Topological manifold Deep learning

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Petrogenesis of Oligocene Granitoids and its Implications on Beryllium Mineralization at Pagele, Nianqingtanggula Mountain(Central Tibet)

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Acta Geologica Sinica(English Edition) 2024年第5期98卷 1202-1225页

作者： ZHANG Linyuan YANG Zhusen HOU Zengqian WU Changda LIU Chang XU Peiyan XIE Lankui Institute of Geology Chinese Academy of Geological Sciences School of Earth and Space Sciences Peking University Institute of Mineral Resources Chinese Academy of Geological Sciences School of Earth Sciences and Resources China University of Geosciences Institute of Geology and Mineral Resources Chengdu Center China Geological Survey

The newly discovered Oligocene granitoids（33.1–28.7 Ma） at Pagele are magmatic rocks related to beryllium mineralization during the India–Asia late-collisional stage. This discovery provides an ideal example to study the latecollisional orogeny and beryllium prospecting in the Lhasa terrane. The Oligocene granitoids include porphyritic granodiorite, Stage Ⅰ, Ⅱ and Ⅲ granites, and granitic pegmatite. Geochemical analysis shows that the porphyritic granodiorite is characterized by high SiO2, K2O, total ΣREE contents, and（La/Yb）N ratios; while the latter two by higher SiO2, lower ΣREE and（La/Yb）N ratios. Notably, the granitic pegmatite has extremely high Y/Ho, low K/Rb and Zr/Hf, and distinct REE tetrad effect（1.14–1.21）. This study suggests that the porphyritic granodiorite may be derived from partial melting of beryllium-rich materials composed of Lhasa ancient crust（70%–80%） and enriched Lhasa lithospheric mantle（20%–30%） under the tearing subduction of Indian slab. The three-stage granites and granitic pegmatite, which contain higher beryllium contents or beryls, were likely generated by highly fractionation of the porphyritic granodioritic magma or other homologous magma. Considering the possible genetic and spatial link between Indian slab tear and rifts, we suggest that highly-fractionated granites in rifting systems represent important Be prospecting targets in the Lhasa terrane.

关键词： beryllium mineralization central Lhasa subterrane enriched Lhasa lithospheric mantle Lhasa ancient crust Oligocene granitoids

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Sedimentary evolution and mangrove dynamics in Dongzhai Harbor， Hainan Island since the Late Pleistocene

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Journal of Earth Science 2024年

作者： Xueyan Yan Yamin Deng Xianzhong Ke Kang Peng Xianjun Xie Yiqun Gan Qinghua Li geological survey， china University of Geosciences School of Environmental Studies， china University of Geosciences Wuhan Center of china geological survey (Central South china Innovation Center for Geosciences) Basin Water Environmental Research Department， Changjiang River Scientific Research Institute

Mangrove wetlands are a vital component of the blue carbon ecosystem， which is of great significance to coastal ecosystems and the global carbon balance. However， mangrove forests worldwide face a combination of natural and anthropogenic threats. This study employs high-resolution sedimentology， geochemistry， and pollen analysis to reveal the sedimentary evolution and vegetation succession in the mangrove wetland of Dongzhai Harbor， Hainan Island. By utilizing multiple proxies， including14C chronology， δ13C， C/N， and the chemical index of alteration （CIA）， we identified three distinct stages in the sedimentary records spanning from the Late Pleistocene to the modern age. Prior to the last glaciation， during the Late Pleistocene， the study area exhibited marine carbonate facies， with an abundance of marine-derived organic matter. During the low sea-level stage of last glaciation， the strata in the cored location were exposed. Following the last glaciation， the study area gradually transitioned into intertidal settings in response to fluctuating sea levels. Since the Middle Holocene or even earlier， sedimentary organic matter continued to accumulate as terrestrial C3 vegetation and mangrove forests established， persisted， and developed. This period witnessed the formation of the current estuarine environment. Simultaneously， the pioneering mangrove species， probably represented by Avicennia， might be initially established， followed by Rhizophora， Bruguiera and Ceriops communities， ultimately being replaced by Kandelia obovata to date. These findings not only fill the gap in the study of paleo-mangroves in china but also contribute valuable knowledge to the global reconstruction of paleo-mangroves， providing crucial reference for the conservation of mangroves and prediction of their responses in the context of climate change.

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Airblast evolution initiated by Wangjiayan landslides in the M_(s)8.0 Wenchuan earthquake and its destructive capacity analysis

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china Geology 2024年第2期7卷 237-247页

作者： Yu-feng Wang Qian-gong Cheng Qi Zhu Department of geological Engineering Southwest Jiaotong UniversityChengdu 610031China Sichuan Highway Planning SurveyDesign and Research Institute LtdChengdu 610041China

Airblasts,as one common phenomenon accompanied by rapid movements of landslides or rock/snow avalanches,commonly result in catastrophic damages and are attracting more and more scientific *** quantitatively analyze the intensity of airblast initiated by landslides,the Wangjiayan landslide,occurred in the Wenchuan earthquake,is selected here with the landslide propagation and airblast evolution being studied using FLUENT by introducing the Voellmy rheological *** results reveal that:(1)For the Wangjiayan landslide,its whole travelling duration is only 12 s with its maximum velocity reaching 36 m/s at t=10 s;(2)corresponding to the landslide propagation,the maximum velocity,28 m/s,of the airblast initiated by the landslide also appears at t=10 s with its maximum pressure reaching594.8 Pa,which is equivalent to violent storm;(3)under the attack of airblast,the load suffered by buildings in the airblast zone increases to 1300 Pa at t=9.4 s and sharply decreased to-7000 Pa as the rapid decrease of the velocity of the sliding mass at t=10 s,which is seriously unfavorable for buildings and might be the key reason for the destructive collapse of buildings in the airblast zone of the Wangjiayan landslide.

关键词： Landslide Voellmy rheological law 3D FLUENT simulation Airblast Intensity Building destructive collapse Wenchuan earthquake geological hazards survey engineering

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New Benthic Fossils from the Late Ediacaran Strata of Southwestern china

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 311-323页

作者： LIU Junping LI Ming TANG Feng ZHAO Jiangtai SONG Sicun ZHOU Ying SONG Xiaohan REN Liudong School of Earth Science and Resources China University of GeosciencesBeijing 10083China Yunnan Institute of geological survey Kunming 650216China Chinese Academy of geological Sciences Beijing 10037China Key laboratory for Stratigraphy and Paleontology MNRCBeijing 10037China School of Earth Science and Engineering Nanjing UniversityNanjing 210093China Department of Earth Sciences University College LondonLondon WC1E 6BTU.K. CAS and Shandong Province Key laboratory of Experimental Marine Biology Center for Ocean Mega-ScienceInstitute of OceanologyChinese Academy of SciencesQingdaoShandong 266071China Institute of Geology Chinese Academy of Geological SciencesBeijing 10037China

The Jiangchuan Biota from the Jiucheng Member(Mb.)of the Dengying Formation(Fm.),discovered in Jiangchuan,eastern Yunnan,china,is marked by copious macrofossils at the apex of the Ediacaran *** fauna features benthic algae with varied holdfasts and other fossils of indeterminate taxonomic affinity and is compositionally unique compared to the Shibantan and Gaojiashan biotas of the Dengying *** the Miaohe and Wenghui biotas of the Doushantuo Fm.,elsewhere in *** novel benthic saccular macroalgal fossil,named here Houjiashania yuxiensis *** ***.,from the Jiangchuan Biota is based on fossils that are sausage-shaped,elongate,tubular,ranging from 0.3 to 4 cm in length,and up to 0.8 cm in *** terminus is blunt and rounded to an obtuse angle,the other is bent with a spread-out surface resembling a holdfast,suggesting a three-dimensional ***,stipe-shaped outgrowths,likely vestiges of sessile saccular life forms,are prevalent in macroalgal fossils of analogous size and shape,as well as present brown algae Scytosiphonaceae,such as Colpomenia and *** new findings augment the diversity of benthic algae,such as those known from the Early Neoproterozoic Longfengshan Biota in North *** benthic algal macrofossils in the Jiucheng *** to knowledge of Late Ediacaran metaphyte diversification and offer more clues about the evolutionary positioning of primitive *** co-occurrence of numerous planktonic and benthic multicellular algae and planktonic microbes might have facilitated ecologically the more extensive later Cambrian explosion evidenced by the Chengjiang Biota in Yunnan.

关键词： paleophytology benthic saccular algae algal evolution Neoproterozoic Jiucheng Member Jiangchuan Biota Yunnan Province

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Late Cenozoic uplift of the Liupan Mountains:Evidence from the Neogene loess deposits

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Science china Earth Sciences 2024年第5期67卷 1480-1488页

作者： Zhilin HE Yansong QIAO Zhengtang GUO Chaoqin CHEN Long CHEN Yang FU Ye YANG Yanxia LIANG Xinru LIN Guoqiao XIAO Tao ZHAN Key laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China CAS Center for Excellence in Life and Paleoenvironment Beijing 100044China University of Chinese Academy of Sciences Beijing 100049China Institute of Ecological Geology survey and Research of Heilongjiang Province Harbin 150030China School of Geography and Information Engineering China University of GeosciencesWuhan 430078China School of Earth Sciences China University of GeosciencesWuhan 430074China Natural Resources survey Institute of Heilongjiang Province Harbin 150036China

The Liupan Mountains,one of the important mountain ranges in western china,are located on the boundary between the northeastern Tibetan Plateau and the Ordos *** uplift history of the Liupan Mountains remains *** deposits are good tracers of regional tectonic and geomorphic changes,because loess is sensitive to erosion and the formation and preservation of loess requires relatively flat highlands and relatively stable tectonic *** investigated the distribution of Neogene loess deposits on the western piedmont of the Liupan Mountains and examined a near-continuous loess section(Nanping section)on the piedmont alluvial *** of magnetic susceptibility stratigraphy with the QA-ⅠMiocene loess sequence dates this 56-m section covering the interval from~8.1 to 6.2 *** lower boundary age of this section,together with previously reported Zhuanglang red clay(sand-gravel layers with intercalated loess during~9–8 Ma and near-continuous loess during~8–4.8 Ma)and Chaona red clay(~8.1–2.58 Ma),indicates that the Liupan Mountains were uplifted in the late Miocene(~9–8 Ma)and basically formed by~8 Ma,attesting to no intense mountain building since that *** addition,based on the information from the Zhuanglang core and the QA-Ⅰsection,we infer that sizable parts of the Liupan Mountains were uplifted during the late Oligocene–early Miocene and did not experience intense uplift during~22–9 Ma.

关键词： Liupan Mountains Mountain building Neogene Loess Chinese Loess Plateau Late Miocene Late Oligocene–early Miocene

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