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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

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Geochemical significance of the Paleogene soda-deposits bearing strata in Biyang Depression,Henan Province

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Science China Earth Sciences 2015年第10期58卷 129-137页

作者： YANG JiangHai YI ChengLong du yuansheng ZHANG ZongHeng YAN JiaXin State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Geological Exploration Institute of Henan Henan Provincial Bureau of Geo-exploration and Mineral Development

The Biyang Depression, lying in the eastern Nanxiang Basin, has a dustpan-shape with faults developed to the southwest and southeast. The Paleogene Hetaoyuan Formation in this depression hosts one of the oldest soda-deposits, the Anpeng deposit. These sodium carbonate-bearing strata consist of lutites, muddy dolomites, and bedded soda-deposits, which are dominated by nahcolite with little trona, mirabilite, and halite. In the top Unit 3 and lower Unit 2 of Hetaoyuan Formation where the sodium carbonates are concentrated, dolomitic shale, muddy carbonate, and sodium carbonate can be separated based on their distinct A1203, TiO〉 Na20, MgO＋CaO, and LOI （loss on ignition） contents. By using Na20/（MgO＋CaO） ratio as an indicator for the relative concentration of Na carbonates to Mg-Ca carbonates, the muddy dolomites can be classified into two groups. One group with Na20/（MgO＋CaO）〈0.6 exhibits a positive correlation between this ratio and AI203＋TiO2 content, an proxy for ter- rigenous clastic input and the other group with Na20/（MgO＋CaO）〉0.6 presents a negative correlation. As the clastic propor- tion decreases, the former indicates that it tends to form pure Mg-Ca carbonates reflecting evaporation less than or equal to re- plenishment for the lake water in a relative humid climate, and the latter reveals a trend to form sodium carbonates with lake water＇s evaporation more than replenishment in a relatively dry climate. From muddy dolomite to sodium carbonate samples, with Na20/（MgO＋CaO） ratio increasing, the A1 normalized Zr, Ti, La, K, Rb, and Ba tend to be enriched and the post-Archean Average Shale （PAAS） normalized positive Eu anomaly becomes more obvious. Integrated with the high B contents and the report of searlesite in the bedded sodium carbonates and the regional extensional tectonic regime, the above geochemical characteristics were interpreted to signify hydrothermal contribution to forming these soda-deposits through the deep fault systems of basin margins.

关键词： sodium carbonate-bearing strata nahcolite evaporation and concentration hydrothermal activity

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U-Pb geochronology of hydrothermal zircon from the Mesoproterozoic Gaoyuzhuang Formation on the northern margin of the North China Block and its geological implications

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Science China Earth Sciences 2011年第11期54卷 1675-1685页

作者： GUO Hua du yuansheng YANG JiangHai GUO Liang Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences Wuhan 430074 China State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China

This paper reports LA-ICP-MS zircon U-Pb ages and REE compositions on detrital zircons （Type 1） and hydrothermal zircons （Type 2） from low-metasedimentary rocks in the Mesoproterozoic Gaoyuzhuang Formation, Pingquan area, Hebei Province that provide important constraints on the tectonic evolution along the northern margin of the North China Block. The detrital zircons are characterized by an oscillatory magmatic core, surrounded by a narrow structureless rim in CL images. They yield 2~7pb/2~tpb ages ranging from 1703 to 2543 Ma with two age peaks at 2473 and 1794 Ma, which is consistent with the Neoarchean and Paleoproterozoic tectono-thermal events recorded in the NCB basement, indicating that the source of the detritus was locally derived. By contrast, the hydrothermal ones are euhedral, sector zoning or internally structureless. They have relatively higher U and Th contents and Th/U ratios （U=139-2918 ppm, Th=35-1327 ppm, Th/U （average） =0.78 vs. U=15-1044 ppm, Th=8-341 ppm, Th/U （average） =0.57 for detrital zircons）. Moreover, they are also enriched in REEs relative to detrital zircons and show a lower positive Ce anomaly （ZREE = 659-2418 ppm vs. 231-611 ppm for detrital zircon; Ce/Ce＊=2-13 vs. 33-174 for detrital zircons）, similar to known hydrothermal zircons derived from many locations. These characteristics, combined with our field petrographic observations, indicate that the hydrothermal zircons possibly formed from a low temperature aqueous fluid. Twelve concordant or near-concordant analyses on hydrothermal zircons yield weighted mean 206pb/238U ages of 325-327 Ma, which provide unambiguous evidence that the northern NCB underwent late Paleozoic low temperature hydrothermal modification. This timing of this hydrothermal event is compatible with that of the late Paleozoic magmatic and metamorphic-deformational events occurred on the northern margin of the NCB, it appears likely that the hydrothermal activity resulted from southward subduction of the Paleo-

关键词： hydrothermal zircon detrital zircon zircon geochronology late Paleozoic North China Block Central Asian Orogenicbelt

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Soft-sediment Deformation Structures Related to Earthquake from the Devonian of the Eastern North Qilian *** Its Tectonic Significance

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Acta Geologica Sinica(English Edition) 2008年第6期82卷 1185-1193页

作者： du yuansheng XU Yajun YANG Jianghai Key Laboratory of Biogeology and Environmental Geology of Education Ministry Wuhan 430074 Faculty of Earth Sciences China University of Geosciences Wuhan 430074

Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin triggered a intense earthquake, and formed seismites and earthquake-related soft-sediment deformation. The soft-sediment deformation structures of Devonian in the eastern North Qilian Mts. consist of seismo-cracks, sandstone dykes, syn-depositional faults, microfoids （micro-corrugated lamination）, fluidized veins, load casts, flame structures, pillow structures and brecciation. The seismo-cracks, syn-depositional faults and microfolds are cracks, faults and folds formed directly by oscillation of earthquake. The seismic dykes formed by sediment instilling into seismic cracks. Fluidized veins were made by instilling into the seismo-fissures of the fluidized sands. The load casts, flame structures and pillow structures were formed by sinking and instilling caused from oscillation of earthquake along the face between sandy and muddy beds. The brecciation resulted from the oscillation of earthquake and cracking of sedimentary layers. The seismites and soft-sediment deformations in Devonian triggered the earthquake related to tectonic activities during the orogeny and uplift of North Qilian Mts.

关键词： North Qilian Mts. seismites soft-sediment deformation Devonian tectonics

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Sedimentary geochemistry and provenance of the Lower and Middle Devonian Laojunshan Formation,the North Qilian Orogenic Belt

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Science China Earth Sciences 2010年第3期53卷 356-367页

作者： XU YaJun du yuansheng YANG JiangHai HUANG Hu Key Laboratory of Biogeology and Environmental Geology of China Education Ministry China University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China

The Laojunshan Formation is a suite of molasse formed during the rapid uplift of the North Qilian Orogenic Belt (NQOB). Forty-one samples of sandstone have been collected from the Sunan and Minle sections in the western sector and the Gulang and Jingyuan sections in the eastern sector of the NQOB belt. Geochemical analyses of those samples indicated: 1) The MgO+Fe2O3T and Al2O3/SiO2 values are higher, and K2O/Na2O ratios are lower in the western sector than those in the eastern sector. 2) All of them are depleted in Nb and Ta elements. The samples from the western sector are depleted in Rb element and enriched with Sc, Co, Ni, V, and Cr elements in the Upper Crust-normalized patterns. However, those from the eastern sector are depleted in Sr without enrichments of Sc, Co, Ni, V, and Cr. 3) All of the samples display a right-inclined REE pattern af- ter Chondrite-normalized REE pattern. But LaN/YbN and Eu/Eu* ratios of the samples from the western sector are lower than those of the samples from the eastern sector. These geochemical characteristics suggest the prominent input of mafic clast with minor granitic rocks into the Sunan area, felsic clast into the Gulang and Jingyuan area, and both mafic and felsic clast into the Minle area. The angular shapes of gravels imply that these ill-sorted sediments were deposited near their sources without recy- cling. Geochemical features above also demonstrated that no major chemical weathering occurred for the western provenance, but deposits in the eastern sector resulted from low or middle degree chemical weathering. Evidences combining tectonic discriminations and comparisons with potential provenances revealed that sediments in the Sunan area were derived mainly from the North Qilian Continental arc, whereas sediments in the Minle, Gulang, and Jingyuan areas were derived not only from the North Qilian Continental arc but also from the basement of the Middle Qilian block. Integrated with the characteristics of development of

关键词： North Qilian Orogenic Belt (NQOB) Laojunshan Formation sedimentary geochemistry provenance orogeny

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Lower Carboniferous carbon isotope stratigraphy in South China: Implications for the Late Paleozoic glaciation

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Science China Earth Sciences 2011年第1期54卷 84-92页

作者： QIE WenKun ZHANG XiongHua du yuansheng ZHANG Yang State Key Laboratory of Geological Process and Mineral Resources China University of Geosciences Wuhan 430074 China Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences Wuhan 430074 China

Studies on carbon isotopes of bulk carbonates from Longan and Baping sections of Lower Carboniferous in Guangxi of China show that the stable carbon isotope compositions in carbonate rocks of the isolated platform and deep slope facies were resistant to the influence of early meteoric diagenesis and late burial diagenesis. Three major positive carbon isotope excursions have been recognized in Lower Carboniferous in South China. The first major positive δ3C shift of 4.19‰ occurred in the middle part of Siphonodella isosticha-upper Siphonodella crenulata zone （Tournaisian）; the second with an amplitude of 4.65‰ occurred near the Tournaisian/Visean boundary; and the third of 2.23‰ in the lower part of Gnathodus bollandensis zone. The three positive shifts of δ3C can be correlated with global carbon isotope excursions and are consistent with the fall in global sea level, indicating that abundant organic carbon burial, lowering of atmospheric CO2, and glaciation may have occurred during these time intervals.

关键词： Carboniferous glaciation carbon isotope Guangxi South China

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黔北—滇东二叠纪锰矿主要成矿规律与成矿区带划分

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矿产综合利用 2024年第1期45卷 62-72页

作者：刘志臣周琦杨瑞东杜远生陈登肖林贵州大学资源与环境工程学院贵州贵阳550003 贵州省地矿局一0二地质大队贵州遵义563003 自然资源部基岩区矿产资源勘查工程技术创新中心贵州贵阳550003 贵州省战略矿床智慧勘查重点实验室贵州贵阳550003 中国地质大学地球科学学院湖北武汉430074

这是一篇地球科学领域的论文。锰矿为我国十分紧缺的战略矿产之一。黔北-滇东地区是我国二叠纪锰矿最典型的分布区,在全球晚古生代也较为少见,该区锰矿资源丰富,找矿潜力巨大,称为“遵义式锰矿”。研究表明,该区锰矿产于二叠纪茅口晚期... 详细信息

这是一篇地球科学领域的论文。锰矿为我国十分紧缺的战略矿产之一。黔北-滇东地区是我国二叠纪锰矿最典型的分布区,在全球晚古生代也较为少见,该区锰矿资源丰富,找矿潜力巨大,称为“遵义式锰矿”。研究表明,该区锰矿产于二叠纪茅口晚期,分布严格受黔北裂谷盆地控制,锰矿在地堑盆地中心喷溢沉积成矿,在地垒区则无锰矿分布,矿体空间展布方向与盆地展布方向基本一致。其中,黔北遵义-黔西地区锰矿在空间上分布于盆地相区,并可分为中心相、过渡相、边缘相等三个锰矿相带,进一步指示了锰矿具体成矿位置,显示了锰矿受盆地中心控制非常明显的特点。在划分的遵义-宣威锰矿成矿带的基础上,详细划分出遵义-黔西锰矿成矿亚带中深溪—八里、龙坪—兴隆、团溪—尚稽、黔西4个锰矿矿集区,以及水城-宣威锰矿成矿亚带中水城—纳雍、格学2个锰矿矿集区。该研究成果对寻找黔北—滇东二叠纪隐伏锰矿床,开展成矿预测,具有重要的意义。

关键词：地球科学二叠纪锰矿成矿规律成矿区带黔北—滇东

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New Zircon U-Pb Age of the Babu Ophiolites in Southeast Yunnan,China and Constrains of Plate Subduction Time

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Acta Geologica Sinica(English Edition) 2017年第3期91卷 1151-1152页

作者： HUANG Hu du yuansheng YANG Jianghai YU Wenchao State Key Laboratory of Oil/Gas Reservoir Geology and Exploitation Chengdu University of Technology State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Objective The Babu ophiolite in Malipo County of southeastern Yunnan is interpreted as remanant ocean crust and represents a possible branch of Paleo-Tethyan Ocean in South China. It consists mainly of mafic and ultramafic rocks. These rocks are very important to understand the evolution of the Paleo-Tethyan Ocean. However, the Babu ophiolite is still disputed and the mafic and ultramafic rocks have been inferred to be part of the Emeishan large igneous province （LIP） by some researchers. In this paper, we present zircon U-Pb data on the metabasalts in Malipo to reveal the formation time of mafic and ultramafic rocks and their tectonic nature.

关键词： Pb ICP MS Th is New Zircon U-Pb Age of the Babu Ophiolites in Southeast Yunnan,China and Constrains of Plate Subduction Time of in

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Growth of a polymetallic nodule from northwestern continental margin of the South China Sea and its response to changes in paleoceanographical environment of the late Cenozoic

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Science China Earth Sciences 2013年第7期56卷 453-463页

作者： ZHANG ZhenGuo du yuansheng WU ChangHang FANG NianQiao YANG ShengXiong LIU Jian SONG ChengBing College of Mining Engineering Hebei United University Faculty of Earth Sciences China University of Geosciences Department of Environment Engineering and Chemistry Luoyang Institute of Technology and Science School of Ocean Sciences China University of Geosciences Guangzhou Marine Geological Survey The Ministry of Land and Resources of China

In the northern South China Sea, the accumulation of enormous quantities of terrigenous sediment during Cenozoic rendered well-developed polymetallic nodules very rare. In this study, we analyzed a polymetallic nodule from the northwestern conti- nental margin of the South China Sea using microscopic mineralogical observation, electron probes, X-ray diffraction （XRD）, ICP-MS, and Be isotope dating. We found the nodule＇s shell layers rich in different types of microstructures, including co- lumnar, laminar, stack-like, petal-like, and porphyritic structures. The major mineral components of the nodule are MnO2. Unlike nodules from the eastern Pacific basin, this nodule has high contents in Fe, Si, A1, and REEs but low contents in Mn, Cu, Co, and Ni. The Mn/Fe ratio is also low and the average REEs content is 1370.4 ppm. There is a strong positive anomaly of Ce; and the Be （beryllium） isotope dating shows the initial time of growth of the nodule to be about 3.29 Ma. The inner compact layer formed from 3.29 Ma to about 1.83 Ma. The laminar and stack-like structures and the low contents of the terri- genous elements such as Fe, Si, REE, and A1 indicate the paleoceanographical environment with weak undersea currents and favorable oxidizing conditions. From 1.83 Ma to 0.73 Ma, the growth rate of the nodule increased by about 3%; the micro- structures formed during this period are stack-like and columnar. The contents of Si and A1 are increased by nearly 10%, indi- cating an increase of terrigenous sediment input in the northern South China Sea. The content of Ce is decreased by about 16% indicating a significant weakening of the oxidizing conditions at the seabed. From 0.73 Ma to 0.69 Ma, the growth rate of the nodule rapidly rose up to 8.27 times that of the nodule＇s average growth rate, and the contents of Fe, A1, and REEs in the layer also increased, forming a loose layer characterized by oolitic, granular, porphyritic, and petal-like structures, indicating the paleocea

关键词： polymetallic nodules growth process late Cenozoic paleoceanographical environment response northwestern conti-nental margin of South China Sea

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New Zircon U-Pb Age of Late Devonian Tuff in Guangxi, South China and the Significance for the Paleo-Tethys Branch Ocean

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Acta Geologica Sinica(English Edition) 2018年第1期92卷 402-403页

作者： HU Lisha du yuansheng XU Yajun WANG Zhiwen WANG Chenghao Collage of Marine Geosciences Key Laboratory of Submarine Geosciences and Prospecting Technology Ocean University of China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology (QNLM) State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Objective The eastern extending range of the Paleo-Tethys Ocean in southwest China has always been focused and controversial. At the beginning of this century some scholars proposed that the Paleo-Tethys Branch Ocean may extend to the Babu-Pingxiang and Cengxi areas along the stouthwestern margin of the South China Block （Cai and Zhang, 2009）. However, the pivotal proof of Late Paleozoic ophoilite and magmatic rocks was absent or sporadical in the Guangxi Zhuang Autonomous Region, resulting in insufficient evidence to support this viewpoint. For the first time this work reported the Late Devonian tuff in the Qinzhou area in the south of the Guangxi Zhuang Autonomous Region and conducted zircon U-Pb dating on it in order to constrain the extension of the Paleo-Tethys Ocean in the South China Block.

关键词： the Paleo-Tethys Branch Ocean New Zircon U-Pb Age of Late Devonian

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