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The Middle and Late Holocene climate change in Bohai Bay revealed by diatom proxy

Journal of Oceanology and Limnology 2024年第5期42卷 1493-1506页

作者： Zhiwen SHANG Jianfen LI Fu WANG Hong WANG Tianjin Centre China Geological SurveyTianjin 300170China Key laboratory of Coastal Geo-environment China Geological SurveyTianjin 300170China Tianjin Key laboratory of Coast geological Processes and Environmental Safety Tianjin 300170China

A total of 98 samples from two boreholes in shallow sea area and two oyster reefs in adjacent coastal plain in the northwestern coast of Bohai Bay were collected for diatom analyses and species *** ratio of the marine species Thalassionema nitzschioides to the intertidal-coastal species complex Cyclotella striata/stylorum serves as a novel proxy for assessing the strength of marine *** data,corrected for the local residence time effect,facilitated the construction of a diatom proxy-based marine influence curve for the study *** curve delineates the dynamics of marine influence and their correlations with paleo-climate fluctuations and the East Asian monsoon variability,as well as their role in chenier *** include:(1)eight periods of intensified marine influence have been documented since 7000 a BP in the study *** peak of each period,as determined by the diatom proxy,corresponds closely to the warm climatic phases and stronger East Asian summer monsoons,suggesting that the peaks marine influence indicate typically the periods of climatic warmth and monsoon activity intensification in the region;(2)a strong correlation exists between the development of cheniers and marine influence,and chenier formation began with the increasing marine influence and terminated at the end of warm periods as marine influence *** climatic changes in the coastal area,as indicated by the diatom proxy,hold significant potential for future related research endeavors.

关键词： Bohai Bay diatom diatom-based marine influence curve paleo-climate Holocene

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Characteristics of Paleontological Communities in Surface Sediments of the Southern South china Sea and Their Paleoclimatic and Paleoenvironmental Significance

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Journal of Earth Science 2024年第1期35卷 144-154页

作者： Jing Zhao Li Zhang Xiaoyan Wang Jinglian Ge Min Xu Wei Chen Mao Luo Qianyong Liang Qiuhua Yu Shuaibing Luo Wenkun Qie Key laboratory of Marine Mineral Resoures Ministry of Natural ResourcesGuangzhou Marine Geological SurveyChina Geological SurveyGuangzhou 511458China National Engineering Research Center for Gas Hydrate Exploration and Development Guangzhou 511458China State Key laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China

Understanding the spatial and temporal distribution of different paleontological communities in the southern South china Sea(SCS)is fundamental to explore its paleoclimatic and paleoenvironmental *** this study,foraminifera,pollen and diatoms from 100 surface sediment samples covering 40000 km^(2) of sea floor in the southern SCS were comprehensively investigated in terms of their assemblage and *** results showed the existence of abundant foraminifera and pollen in most of the samples,although diatom communities were relatively *** were dominated by ***,***,***,while diatoms were characterized by ***,*** and ***,indicating a typical tropical marine *** pollen assemblages showed a better reflection of montane rainforest,tropical rainforest and *** spatial differences among foraminifera assemblages may indicate the effect of water depth and a warmer environment in the southeast part of the study area,while the spatial patterns of diatom and pollen assemblages imply the influence of coastal *** study also noted that the compositions of paleontological communities in the SCS can vary significantly in a short distance,and synthesized studies on multiple biological groups are needed to reconstruct the Quaternary climate and the oceanographic environment.

关键词： southern South china Sea sediments foraminifera diatom pollen

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Multistate transition and coupled solid-liquid modeling of motion process of long-runout landslide

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2694-2714页

作者： Yang Gao Yueping Yin Bin Li Han Zhang Weile Wu Haoyuan Gao Institute of Geomechanics Chinese Academy of Geological SciencesChina Geological SurveyBeijing100081China Key laboratory of Active Tectonics and geological Safety Ministry of Natural ResourcesBeijing100081China china Institute of geological Environment Monitoring China Geological SurveyBeijing100081China School of geological Engineering and Geomatics Chang’an UniversityXi’an710054China

The recognition,repetition and prediction of the post-failure motion process of long-runout landslides are key scientific problems in the prevention and mitigation of geological *** this study,a new numerical method involving LPF3D based on a multialgorithm and multiconstitutive model was proposed to simulate long-runout landslides with high precision and *** following results were obtained:(a)The motion process of landslides showed a steric effect with mobility,including gradual disintegration and *** sliding mass can be divided into three states(dense,dilute and ultradilute)in the motion process,which can be solved by three dynamic regimes(friction,collision,and inertial);(b)Coupling simulation between the solid grain and liquid phases was achieved,focusing on drag force influences;(c)Different algorithms and constitutive models were employed in phase-state *** volume fraction is an important indicator to distinguish different state types and solid‒liquid *** flume experimental results were favorably validated against long-runout landslide case data;and(d)In this method,matched dynamic numerical modeling was developed to better capture the realistic motion process of long-runout landslides,and the advantages of continuum media and discrete media were combined to improve the computational accuracy and *** new method can reflect the realistic physical and mechanical processes in long-runout landslide motion and provide a suitable method for risk assessment and pre-failure prediction.

关键词： Long-runout landslide Multistate transition Mixed solid‒liquid flow Post-failure process Numerical simulation

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First Record of Middle Eocene Elephant Ancestors’Footprints in the Gonjo Basin,East Tibet Plateau

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Journal of Earth Science 2024年第4期35卷 1224-1235页

作者： Asma Tahir Huazhou Yao Junaid Khan Yangui Li He Zhao Yue Yu Tang Yuan Institute of geological survey China University of GeosciencesWuhan430074China Wuhan Center China Geological SurveyWuhan430205China State Key laboratory of geological Processes and Mineral Resources Wuhan430078China Chengdu Center China Geological SurveyChengdu610081China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

It is the first time that the fossil footprints of a group of Middle Eocene elephant ancestors have been discovered in the Gonjo Basin,East Tibet *** Gonjo Formation is attributed to the Middle Eocene Epoch(U-Pb age=44.7±1.2 Ma)and consists mainly of purplish-red,medium-to coarse-grained sandstones,siltstones interbedded with mudstones,and conglomerates with sedimentary structures like ripple marks,rip-up clasts,and trough-cross bedding,suggesting fluvial-lacustrine *** group of fossil footprints has a characteristic oval-concave shape,and the toe impressions are *** fossil footprints are overstepped with a pockmarked texture resembling Proboscipeda *** than 165 fossil footprints of the group are relatively well-preserved with different diameters,which is evidence of highly social behavior and trackmakers of different ages,including calves,juveniles,adolescents,and *** size frequency of the fossil footprints enabled us to deduce the body mass,shoulder height,and hip-height distribution of the trackmakers that crossed the East Tibet Plateau 44.7 Ma *** trackmakers comprised an estimated average hip-height of 111.8 cm,an average shoulder height of 172.8 cm for males/155.9 cm for females,and an average body mass of approximately 1218.1 kg for males/907.8 kg for *** abundance of fossil footprints reveals that in the Middle Eocene Epoch,the environment was extraordinarily conducive for the elephant ancestors to live in the East Tibet region.

关键词： Proboscipeda enigmatica East Tibet Plateau Gonjo Formation fossil footprints fluvial-lacustrine

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Middle Devonian ostracods from Jiwozhai patch reef(Dushan,Guizhou Province,South china):Biostratigraphic and palaeoecological implication

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Journal of Palaeogeography 2024年第3期13卷 581-593页

作者： Jun-Jun Song Jia-Yuan Huang Wen Guo Kun Liang Yu-Cong Sun Zhi-Hong Wang Wen-Kun Qie State Key laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008Jiangsu ProvinceChina Hubei Key laboratory of Paleontology and geological Environment Evolution Wuhan Center of China Geological SurveyWuhan 430205Hubei ProvinceChina University of Chinese Academy of Sciences NanjingNanjing 211135Jiangsu ProvinceChina

The Middle Devonian ostracods from the Jiwozhai patch reef in Dushan, Guizhou Province, South china were described for the first time in this study. Twenty-nine species belonging to 20 genera were identified and figured, including a new species named Wangshangkia jiwozhaiensis sp. nov. The ostracod fauna in the Jiwozhai patch reef represents a Givetian age. The ostracod assemblage belongs to the smooth-podocopid association, which is also ecologically equivalent to the Eifelian Mega-Assemblage Ⅲ. This association is indicative of shallow open-marine environments. The Jiwozhai patch reef fauna is primarily comprised of suspension feeders, including filter-feeding ostracods, corals, brachiopods and bryozoans. Ostracods from the Jiwozhai patch reef were compared to the ostracod faunas from Laurentia-Baltica at generic level, which reveals limited faunal exchanges between South china and Laurentia-Baltica during the Middle Devonian.

关键词： Ostracods Givetian Jiwozhai patch reef Dushan Palaeoecology

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A New Discovery of Mineralization as Subseafloor Hydrothermal Replacement in the Duddar Super-Large SEDEX Lead-Zinc Deposit in Pakistan

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Journal of Earth Science 2024年第3期35卷 1075-1078页

作者： Huishan Zhang Yucai Song Jianing Sun Jun Hong Yasir Shaheen Khalil Yanguang Li Haidi Zhang Zhihua Wang MNR Key laboratory for the Study of Focused Magmatism and Giant Ore Deposits Xi’an Center of Geological SurveyChina Geological SurveyXi’an 710054China Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Chengdu Center of geological survey China Geological SurveyChengdu 610081China china Huaye Group Co. LtdBeijing 100037China geological survey of Pakistan Islamabad 44000Pakistan

0 INTRODUCTION Sedimentary exhalative(SEDEX)lead-zinc deposit was traditionally considered as a result of submarine hydrothermal exhalation,including exhalative plume and brine pool models(Izanloo et al.,2022;Spinks et al.,2021;Maghfouri et al.,2020;Sangster,2020,2018;Huang et al.,2019;Rajabi et al.,2015;Goodfellow and Lydon,2007;Large et al.,2005,2001;Peng et al.,2000;Goodfellow et al.,1993;Figures 1a,1b).However,recognition of mineralization as subseafloor hydrothermal replacement in a few SEDEX deposits has challenged the traditional consideration(Magnall et al.,2023,2021,2020a,b;Hayward et al.,2021;Figure 1c).Researchers come to believe that subseafloor replacement rather than submarine exhalation is a dominant process for SEDEX mineralization,but this needs to be examined through more case studies.

关键词： submarine mineralization seafloor

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Ordovician integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

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Science china Earth Sciences 2024年第4期67卷 971-1004页

作者： Xiang FANG Yong Yi ZHEN Guangxu WANG Xin WEI Zhongyang CHEN Yan LIANG Xuejin WU Wenjie LI Chao LI Renbin ZHAN Yuandong ZHANG State Key laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China geological survey of New South Wales W.B.Clarke Geoscience CentreNSW 2753Australia University of Chinese Academy of Sciences Beijing 100049China

The Ordovician rocks on the Qinghai-Tibetan Plateau represent the oldest non-metamorphic strata,and are critical to understanding the history of regional geology and biotic evolution of the entire *** of Floian,Darriwilian,Sandbian,Katian and Hirnantian are represented in the plateau with a hiatus of variable duration occurring underneath the basal Ordovician across the *** stratigraphical regions,including the Himalaya,Gangdise-Zayu,Qiangtang-Qamdo,Songpan-Garze,and Karakoram-Kunlun-Altun,are differentiated for the Ordovician strata,which are correlated with their equivalents in the Sibumasu,Indochina,Qaidam-Qilian,Tarim-Tianshan,and the Yangtze(western margin)stratigraphical *** the QinghaiTibetan Plateau,graptolites,conodonts,and cephalopods are the most common and useful fossils for the Ordovician *** Ordovician biotas of the Qinghai-Tibetan Plateau bear some distinguishable palaeobiogeographical signatures,among which the cephalopods are characterized by the flourishing actinocerids of North china affinity in the Early-Middle Ordovician,and by the thriving lituitids and orthocerids of South china affinity in the Middle-Late *** occurrences and their palaeobiogeographical evolution provide critical evidence bearing on the reconstruction of the geological history of the Qinghai-Tibetan Plateau and surrounding terranes in northeastern *** stratigraphical successions of the Cambrian-Ordovician transition in the Himalaya and Lhasa and nearby Sibumasu terranes were significantly affected by the Kurgiakh Orogeny,which resulted in the extensive unconformity between the Ordovician and the underlying rocks in most areas of the Qinghai-Tibetan *** southern Xizang,a warm-water biota of Middle Ordovician age was recovered from oolitic limestones,suggesting a likely palaeogeographical location in low-latitudes near the *** the Himalaya and Sibumasu regions,the Upper Ordovician was typified by t

关键词： Ordovician Chronostratigraphy Lithostratigraphy Biostratigraphy Palaeobiogeography Qinghai-Tibetan Plateau

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Timing and Tectonic Setting of the Gaoaobei TungstenMolybdenum Deposit in Nanling Range, South china

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Journal of Earth Science 2024年第3期35卷 890-904页

作者： Jianfeng Li Kemeng Ma Youyue Lu Jianming Fu Shunbo Cheng Yuan Li Chuanbiao Li College of Geographical Science Liaoning Normal UniversityDalian 116029China Wuhan Center of geological survey China Geological SurveyWuhan 430205China Granite Diagenesis and Mineralization Geology Research Center China Geological SurveyWuhan 430205China Mineral Resources survey Institute of Hunan Province Changsha 410083China

The Gaoaobei tungsten-molybdenum deposit is a newly discovered large-scale quartzvein-type deposit in the Nanling metallogenic belt in South *** ore bodies are hosted in the Indosinian granites and the Cambrian Xiangnan Group slates and are controlled by NWW-oriented faults,which are obviously different from the“five-story building”model in southern Jiangxi *** magmatic rocks in the study area are dominated by medium-to coarse-grained biotite monzogranite,with a few NW-oriented fine-grained granite *** medium-to coarse-grained biotite monzogranite and fine-grained granite dykes have zircon U-Pb ages of 229.4±1.9 Ma(MSWD=1.5)and 164.9±3.3 Ma(MSWD=0.75),respectively,corresponding to the Indosinian and Yanshanian *** monzogranites have higher contents of FeO,CaO,K2O,P2O5,and TiO2,while the granite dykes have slightly higher contents of SiO2,Al2O3,MnO,and *** A/CNK values are 1.11-1.75 and 1.19-2.25,and the contents of CIPW normative corundum are 1.71%-6.66%and 2.41%-9.50%,suggesting both the monzogranites and granite dykes are S-type *** total amount of rare earth elements in the monzogranites(from 84.7 ppm to 129 ppm)is slightly lower than that in the granite dykes(from 128 ppm to 133 ppm).The Eu/Eu*values range from 0.12 to 0.30 in monzogranites and from 0.0011 to 0.0013 in granite dykes,indicating the fine-grained granites underwent more intense fractional *** monzogranite and granite dykes have high 87Sr/86Sri values of 0.7169-0.7193 and 0.72825-0.72880,lowεNd(t)values ranging from-10.2 to-9.6 and from-11.5 to-11.4,and TDM2 ages of 1835-1785 and 1957-1946 Ma,*** isotope data indicate their origin from the remelting of the Paleoproterozoic crustal *** with regional geology,it is concluded that the medium-to coarse-grained biotite monzogranite was formed in a post-collisional extensional *** addition,40Ar-39Ar dating of the greisen type tungsten-molybdenum ore gave

关键词： zircon U-Pb age 40Ar-39Ar age geochemistry tungsten molybdenum deposit Gaoaobei Nanling Range.

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Petrogenesis and Tectonic Implications of the Early Triassic Nianzi Adakitic Granite Unit in the Yanshan Fold and Thrust Belt:New Constraints from U-Pb Geochronology and Sr-Nd-Hf Isotopes

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 50-66页

作者： ZHANG Huijun WU Chu HE Fubing WANG Biren CUI Yubin LIU Zhenghua YOU Shina DONG Jing Development and Research Center of the china geological survey Beijing 100037China Beijing Institute of the geological survey Beijing 100095China Institute of Disaster Prevention LangfangHebei 065201China

The Nianzi granite unit,which includes the Nianzi,Xiaolianghou and Xiawopu granitic intrusions,is a significant component of the northern part of the North china Craton(NCC)and is situated in the Yanshan fold and thrust belt(YFTB).However,there is still debate regarding the tectonic evolutionary history of the YFTB during the late Permian to Triassic period,specifically regarding the timing of subduction and collision between the NCC and the Paleo-Asian *** Nianzi granite unit exhibits unique petrological,geochronological and geochemical signatures that shed light on the tectonic evolutionary history of the *** study presents detailed petrology,whole-rock geochemistry,together with Sr-Nd isotopic,zircon U-Pb dating and Lu-Hf isotopic data of the granites within the Nianzi granite *** findings demonstrate that the granites primarily consist of subhedral K-feldspar,plagioclase,quartz,minor biotite and hornblende,with accessory titanite,apatite,magnetite and *** U-Pb dating indicates that the Xiaolianghou granite was emplaced at 247.5±0.62 ***,the adakitic characteristics of the Nianzi,Xiawopu and Xiaolianghou granitic intrusions,such as high Sr and Ba contents and high ratios of Sr/Y and(La/Yb)N,combined with negative Sr-Nd and Lu-Hf isotopes(87Sr/86Sr)i=0.705681–0.7057433,εNd(t)=−21.98 to−20.97,zirconεHf(t)=−20.26 to−9.92,as well as the I-type granite features of high SiO_(2),Na_(2)O and K_(2)O/Na_(2)O ratios,enriched Rb,K,Sr and Ba,along with depleted Th,U,Nb,Ta,P and Ti,suggest that the Nianzi granitic unit was mainly derived from the partial melting of a thickened lower crust containing hydrous,calc-alkaline to high-K calc-alkaline,mafic to intermediate metamorphic *** light of these parameters,we further integrate our data with previous studies and conclude that the Nianzi granitic unit was generated in a post-collisional extensional environment during the Early Triassic.

关键词： tectonic evolution zircon geochronology Sr-Nd-Hf isotopes Nianzi granite unit Yanshan fold and thrust belt

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Quaternary Activity Characteristics and Regional Tectonic Significance of the Jiulong Fault in Jiujiang,Jiangxi Province,china

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Journal of Earth Science 2024年第4期35卷 1107-1117页

作者： Xin Qi Yuyong Jiao Qinghua Li Bin Li Faculty of Engineering China University of GeosciencesWuhan430074China Wuhan Center China Geological SurveyWuhan430205China Institute of geological survey China University of GeosciencesWuhan430074China

Obtaining geological and landform dislocation features,as well as the measured stratigraphic activity age,provides direct evidence to evaluate fault activity,which is more difficult to do in areas with low tectonic activity,such as eastern and central china.A detailed investigation of the fault activity,trenching,drilling joint geological profile,geological survey,and chronological analysis were used to obtain the spatial geometry,fault kinematics,and activity chronology of the Jiulong *** conclusions are as follows:(1)The Jiulong fault was a fracture zone composed of four branch faults,with a width of around 30–40 m and good extendibility,while the maximum surface rupture length was 373 m.(2)The Jiulong fault has many strata dislocations,and the dislocation distance decreased from bottom to top,demonstrating synsedimentary structure characteristics,with a maximum stratigraphic dislocation distance of 18.2 m.(3)Preliminary analysis suggested the Jiulong fault as a secondary fracture of the Xiangfan-Guangji fault zone and provided evidence of the southeastward extension of the Xiangfan-Guangji fault.A preliminary hypothesis purported the Xiangfan-Guangji fault as the seismogenic fault of the Ms 5.0 magnitude earthquake in 1911.(4)According to OSL and ESR dating analyses,the upper breakpoint of the Jiulong fault cuts into the Late Pleistocene Xingang Formation(Qp3x)strata,and the latest active age of the Jiulong fault was 57.6 *** chronology analysis confirmed an active fault from the Late Pleistocene and identified a weak tectonic in Jiujiang Province,which represents the largest active fault outcrop uncovered in the area so *** study provides evidence and research materials for the evaluation of fault activity and seismic stability in this region.

关键词： active fault regional tectonic earthquakes seismic intensity tectonics

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