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Provenance of the Lower Jurassic pyroclastic sediments in the Zigui Basin:Implication for crustal thickening in the eastern Qinling orogenic belt

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Science China earth sciences 2024年第1期67卷 196-207页

作者： Rong CHAI Jianghai YANG Yuansheng DU Chengshan WANG school of earth sciences and resources China University of Geosciences(Beijing)Beijing 100023China school of earth sciences China University of Geosciences(Wuhan)Wuhan 430074China Chinese Academy of Geological sciences Beijing 100037China

The Late Triassic witnessed significant collisional orogenic events in the Qinling orogenic belt,accompanied by magma underplating and tectonic *** processes potentially resulted in substantial crustal thickening and uplift of the Qinling ***,due to the absence of igneous rock records from this period in the eastern section of the Qinling orogen,the changes in crustal thickness during this orogenic process have not been thoroughly investigated.A series of foreland basins emerged during the Early Mesozoic to the south of the East Qinling orogenic *** basins have preserved clastic sedimentary rocks derived from the uplift and erosion of the orogenic *** sedimentary records serve as crucial records to reconstruct the evolutionary history of the Qinling *** further clarify the collisional orogenic process of the Qinling orogenic belt,this study conducted in situ volcanic lithic fragment geochemistry,detrital zircon U-Pb chronology and trace element composition analysis on the sandstones of the Lower Jurassic Tongzhuyuan Formation in the Zigui *** results suggest that the sandstones,which exhibit a significant abundance of volcanic lithic fragments,has a characteristic detrital zircon age group of 250–200 Ma,indicating a major provenance from the Triassic volcanic *** with regional correlation and paleocurrent analysis,the detrital zircon U-Pb age data show that the source area of volcanic rocks should be in the Qinling orogenic belt to the north of the *** interpretation is further supported by the Triassic granitic rocks exposed in the western part of the orogenic belt,representing the magmatism during the Triassic collisional orogenesis in the Qinling *** on the co-varying relationships between present-day crust thickness with the chemical compositions of granite rocks and zircons,the La/Yb ratio of volcanic lithic fragments in the Tongzhuyuan Formation and the Eu/Eu*ratio of detrital zircon

关键词： Qinling orogenic belt Zigui Basin Late Triassic Detrital zircons Crustal thickening

The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul B.Wignall David P.G.Bond school of earth & Environment University of Leeds school of Environmental sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Zircon Hf Isotope Mapping for Understanding Crustal Architecture and Its Controls on Mineralization during Early Cretaceous in the Southern Great Xing'an Range,NE China

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Journal of earth Science 2024年第1期35卷 41-50页

作者： Feng Yuan Huanan Liu Shengjin Zhao Mingjing Fan State Key Laboratory of Geological Processes and Mineral resources Collaborative Innovation Center for Exploration of Strategic Mineral ResourcesSchool of Earth ResourcesChina University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral resources School of Earth Sciences and ResourcesChina University of GeosciencesBeijing100083China No.10 Institute of Geological Exploration Inner Mongolia Bureau of Geology and Mineral ResourcesChifeng 024000China Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China

Voluminous Early Cretaceous granitoids and associated large-scale ore deposits are distributed within the southern Great Xing'an Range(SGXR),NE *** on previously published geochronology and zircon Hf-isotope data,Hf isotope mapping is undertaken to improve our understanding of crustal architecture and its controls on ore *** ore-related Early Cretaceous granitoids were sourced predominantly from juvenile crust,with the involvement of variable proportions of ancient crustal *** crustal architecture,as inferred from Hf isotopic contour maps,indicates two distinct Hf isotopic domains in SGXR,including(1)a higher-ε_(Hf)(+7 to+11)juvenile crust containing minor ancient crustal material,and(2)a lower-ε_(Hf)(+2 to+6)juvenile crust containing a greater proportion of ancient crustal *** Hf isotopic maps identify links between crustal architecture and regional *** deposits and other deposits with significant Cu production are restricted mainly to the higher-ε_(Hf)juvenile crustal regions in the northern and eastern *** dominated by other metals(e.g.,Mo,Sn,W,Pb,Zn,and Ag)occur mainly in the lower-ε_(Hf)juvenile crustal regions in the southern and western *** between juvenile crust-derived melts and ancient crustal components played an important role on the distribution of various ore metals.

关键词： Hf isotope mapping crustal architecture large-scale Early Cretaceous granitoids distribution of ore deposits southern Great Xing'an Range zircon

A synthesis of the Cretaceous wildfire record related to atmospheric oxygen levels?

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Journal of Palaeogeography 2024年第1期13卷 149-164页

作者： Da-Wei Lü Wen-Xu Du Zhi-Hui Zhang Yuan Gao Tian-Tian Wang Jin-Cheng Xu Ao-Cong Zhang Cheng-Shan Wang Shandong Provincial Key Laboratory of Depositional Mineralization and Sedimentary Minerals College of Earth Sciences and EngineeringShandong University of Science and TechnologyQingdao 266590Shandong ProvinceChina school of earth sciences and resources China University of GeosciencesBejing 100083China Institute of earth sciences China University of Geosciences(Bejing)Beijing 100083China

The Cretaceous was a significant greenhouse period in earth's history with higher atmospheric CO_(2) levels and temperatures than today. Although evidence of combustion has been widely described from the Cretaceous deposits, our understanding of the spatiotemporal diversification pattern and process of the Cretaceous wildfires is still limited. In this study, we comprehensively synthesize a total of 271 published Cretaceous wildfire occurrences based on the by-products of burning, including fossil charcoal, pyrogenic inertinite(fossil charcoal in coal), and pyrogenic polycyclic aromatic hydrocarbons(PAHs). Spatially, the dataset shows a distinctive distribution of reported wildfire evidence characterized by high concentration in the middle latitudinal areas of the Northern Hemisphere(30°N-60°N) over the Cretaceous. Temporally, an overall increasing trend of the reported wildfire data from the Early Cretaceous to the Late Cretaceous is coincident with higher atmospheric O_(2) levels. However, the spatial and temporal patterns may result from many types of factors, such as taphonomy, preservation, and researcher biases, instead of a real picture of the Cretaceous wildfire evolution. To better understand the spatiotemporal diversification of the Cretaceous wildfire, more investigations on the record of wildfire occurrences during this period would be necessary in the future.

关键词： Wildfire Cretaceous Atmospheric oxygen Taphonomy Charcoal

Effect of Iron on the Stability of Rhodochrosite at the Topmost Lower Mantle Conditions

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Journal of earth Science 2024年第2期35卷 504-513页

作者： Tianlei Zhai Fei Qin Shengxuan Huang Shan Qin Yu Gong Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of EducationSchool of Earth and Space SciencesPeking UniversityBeijing100871China school of earth sciences and resources China University of GeosciencesBeijing100083China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China

Carbonates are viewed as the principal oxidized carbon carriers during subduction,and thus the stability of subducted carbonates has significant implications for the deep carbon *** we investigate the high pressure-temperature behaviors of rhodochrosite in the presence of iron up to∼34 GPa by in-situ X-ray diffraction and ex-situ Raman *** relatively low temperature below∼1500 K,MnCO_(3)breaks down into MnO and CO_(2).Upon heating to∼1800 K,however,the MnCO_(3)-Fe^(0)reactions occur with the formation of Mn_(3)O_(4),Fe^(O)and reduced carbon.A'three-stage'reaction mechanism is proposed to understand the kinetics of the carbon-iron-manganese redox *** results suggest that Fe^(0)can serve as a reductant to greatly affect the stability of rhodochrosite,which implies that the effect of Fe-metal should be seriously considered for the high pressure-temperature behaviors of other predominant carbonates at earth's mantle conditions,particularly at depths greater than∼250 km.

关键词： deep carbon cycle rhodochrosite reduced mantle diamond formation high pressure tectonics geochemistry

Identification of carbonates with high positive carbon isotope excursion from the Liaohe Group in the northeastern North China Craton and implications for the Lomagundi-Jatuli Event

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Science China earth sciences 2024年第9期67卷 2824-2844页

作者： Hongyu WANG Shuanhong ZHANG Sen WANG Linghao KONG Yue ZHAO Qiqi ZHANG Sen GAO Guohui HU Institute of Geomechanics Chinese Academy of Geological Sciences Key Laboratory of Paleomagnetism and Tectonic Reconstruction Ministry of Natural Resources SinoProbe Laboratory Chinese Academy of Geological Sciences school of earth Science and Mineral resources China University of Geosciences

The Great Oxidation Event（GOE） during the early Paleoproterozoic represents the first significant buildup in earth's atmospheric oxygen and resulted in a series of significant changes in the earth's surface environment. Among them is the 2.22（or 2.33）–2.06 Ga Lomagundi-Jatuli Event（LJE）, which is globally, the largest magnitude and longest duration, marine carbonate positive carbon isotope excursion(δ13CV-PDB>10‰) known. This event has attracted the attention of scholars all over the world. However, except for a high positive carbon isotope excursion(δ13CV-PDB>10‰) recently identified from marine carbonate rocks within the Daposhan Formation in the lower Fanhe Group（or the Sanchazi Group） in the Longgang Block in the northeast North China Craton（NCC）, Paleoproterozoic carbonates in the NCC are characterized by a low-amplitude positive carbon isotope excursion(δ13CV-PDB10‰） of marine carbonate rocks occurred at about 2.15 *** comparisons of different s

关键词： Lomagundi-Jatuli Event (LJE) Great Oxidation Event (GOE) Carbon-oxygen isotopes Liaohe Group Marine carbonate Jiao-Liao-Ji Belt North China Craton

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The genesis and resource potential of gold deposits in the Liaodong Peninsula

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Science China earth sciences 2024年第3期67卷 657-672页

作者： Rixiang ZHU Jin-Hui YANG Gongwen WANG Qingdong ZENG Guoqiang XUE Tao XU Xinghui LI Peng ZHANG Da LEI Guang ZHU State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China school of earth sciences and resources China University of GeosciencesBeijing 100083China Shenyang Center China Geological SurveyShenyang 110034China school of resources and Environmental Engineering Hefei University of TechnologyHefei 230009China

Plenty of gold deposits related to Late Mesozoic craton destruction are widely distributed in eastern North China Craton. However, significant differences in research degrees, ore-forming characteristics, and proven reserves exist among different regions in the North China Craton. The Liaodong Peninsula has similar regional geological characteristics to those of the Jiaodong Peninsula, with both experiencing craton destruction during Late Mesozoic, but the two areas have substantial differences in terms of gold mineralization and the proven gold resources. Based on regional geology, Mesozoic magmatictectonic evolution and ore geology, combined with integrated geophysical exploration and big data AI resource prediction, in this paper, we propose that the ore-forming materials of Late Mesozoic gold deposits in Liaodong were mainly originated from mantle-derived melts and/or fluids induced by craton destruction. The gold deposits were primarily controlled by NE-NNEtrending faults, mainly classified as fracture-controlled altered rock-type and sulfide-bearing quartz vein-type. Moreover, our study predicts that the Yalu River fault zone and its related secondary faults, as well as the periphery and deeper parts of known goldfields, are the important regions for future gold resource exploration. The Yalu River metallogenic belt has an enormous potential for gold resources, and the Liaodong Peninsula has a potential to add thousands of tons of gold resources.

关键词： Liaodong Peninsula Gold deposit Integrated geophysical exploration Prospecting potential Direction for prospecting breakthroughs

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Druse Calcite Crystals Formed by Mesoproterozoic Paleo-earthquake Activity in the Northern Margin of the North China Craton

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Journal of earth Science 2024年第2期35卷 514-524页

作者： Yueshuang Du Zhiguang Zhou Guosheng Wang Chen Wu Wenchao Xu school of earth sciences and resources China University of GeosciencesBeijing100083China Key Laboratory of Continental Collision and Plateau Uplift Institute of Tibetan Plateau Researchand Center for Excellence in Tibetan Plateau Earth SciencesChinese Academy of SciencesBeijing100101China No.1 Institute of Geological and Mineral resources Survey Henan Bureau of Geo-Exploration&Mineral DevelopmentLuoyang471000China

The Meso-neoproterozoic Bayan Obo rift is located along the northern margin of the North China Craton,and was associated with the break-up of the Columbia *** rift evolution,syn-sedimentary deformation occurred due to tectonic activity and *** events are recorded in the Jianshan Formation of the Bayan Obo Group,Inner Mongolia,as soft sediment deformation structures in the central Bayan Obo *** calcite crystals and collapse breccias in the Jianshan Formation may provide information on the rift *** druse calcite crystals are idiomorphic-columnar in shape and associated with graphite,pyrite,and quartz.δ^(13)C values of the graphite are−20‰,indicative of biogenic deoxygenation and formation in *** druse calcite crystals are inorganic in origin and formed in water at a temperature of 55℃,based on calciteδ^(13)C andδ^(18)O *** calcite grew in paleo-caves containing fault breccias,with heat derived from *** such,the druse calcite crystals are important evidence for seismic *** collapse breccias(i.e.,fault breccias)and other indicators of slip show that displacement occurred from NE to SW,which is different from the paleocurrent direction in the Jianshan *** thickness of the collapse breccia is∼200 m,which represents the height of the fault *** strike of the fault scarp was NE-SW,based on the distribution of the collapse *** Bayan Obo and Yanliao rifts experienced rapid NW-SE extension,and developed similar deformation structures at ca.1.6 Ga related to break-up of the Columbia supercontinent.

关键词： North China Craton druse calcite crystals paleo-earthquake activity collapse breccia Bayan Obo rift Proterozoic

An Advanced Image Processing Technique for Backscatter-Electron Data by Scanning Electron Microscopy for Microscale Rock Exploration

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Journal of earth Science 2024年第1期35卷 301-305页

作者： Zhaoliang Hou Kunfeng Qiu Tong Zhou Yiwei Cai Frontiers Science Center for Deep-time Digital earth China University of GeosciencesBeijing 100083China Department of Geology University of ViennaVienna 1090Austria State Key Laboratory of Geological Processes and Mineral resources School of Earth Sciences and ResourcesChinaUniversity of GeosciencesBeijing 100083China

Backscatter electron analysis from scanning electron microscopes(BSE-SEM)produces high-resolution image data of both rock samples and thin-sections,showing detailed structural and geochemical(mineralogical)*** allows an in-depth exploration of the rock microstructures and the coupled chemical characteristics in the BSE-SEM image to be made using image processing *** image processing is a powerful tool for revealing the more subtle data“hidden”in a picture,it is not a commonly employed method in geoscientific microstructural ***,we briefly introduce the general principles of image processing,and further discuss its application in studying rock microstructures using BSE-SEM image data.

关键词： Image processing rock microstructures electron-based imaging data mining