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Impact-derived features of the Xiuyan meteorite crater

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Chinese Science Bulletin 2008年第3期53卷 392-395页

作者： CHEN Ming guangzhou institute of geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Up to now,176 meteorite impact craters have been found on the *** these craters,none of them lies in *** Xiuyan crater is located in the Liaodong Peninsula of *** bowl-shaped crater has a diameter of 1.8 km and depth of about 150 *** impact-derived features include planar deformation features(PDFs)in quartz,shatter cones,impact breccia,and radial valleys on the wall of *** is the first confirmed meteorite impact crater in China.

关键词：陨石撞击坑震动变质作用平面变形特征石英

High-resolution sedimentary record of hydrocarbon contaminants in a core from the major reaches of the Pearl River, China

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Chinese Science Bulletin 2000年第S1期45卷 97-104页

作者： MAI Bixian SHENG Guoying LIN Zheng ZHANG Gan MIN Yushun FU Jiamo State Key Laboratory of Organic geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Guangdong Key Laboratory of Environmental Protection and Resources Utilization Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

The concentrations and compositions of hydrocarbon contaminants, and molecular marker indices in modern sediments from a core in the major reaches of the Pearl River were investigated. The sedimentary record of hydrocarbons in the core, in combination with 210Pb-dating, was used to reconstruct the pollution history of hydrocarbon pollutants in the Pearl River in the past 100 years.

关键词： organic contaminants sedimentary record sedimentary core.

Crustal magma oxidation state and endowments in porphyry copper deposits

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Science China Earth Sciences 2025年第1期 226-236页

作者： Yumin AI Massimo CHIARADIA Chao WU Huayong CHEN Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Earth Sciences University of Geneva Guangdong Provincial Key Laboratory of Mineral Physics and Materials

Porphyry copper deposits（PCDs） supply the majority of the world's copper（Cu） as well as significant amounts of molybdenum（Mo） and gold（Au）. The formation of these deposits is controlled by a variety of geological factors, among which the magmatic oxidation is one of the focuses of current research. This study investigates the redox characteristics of arc magmas by analyzing the ratio of vanadium（V） to scandium（Sc） and its correlation with the oxygen fugacity （fO2） of magmas from arcs of various crustal thicknesses globally. We compiled an extensive dataset of published V/Sc values and studied the partition coefficients of Vand Sc between minerals and silicate melts across various magmatic environments. The results demonstrate that fractional crystallization of magnetite markedly reduces V/Sc values of the residual melt. Furthermore, magnesium number（Mg#） at the onset of magnetite fractionation is strongly positively correlated with fO2of the equilibrium magma. Based on this,the oxidation of arc magmas from different crustal thicknesses can be evaluated. The result suggests that magmas generated in crusts thicker than 20 km tend to be more oxidized with increasing crust thickness. This trend is attributed to enhanced intracrustal differentiation processes involving garnet and amphibole, particularly in mature island and continental arcs. In contrast,magmas in thinner arc crusts（<20 km）, which are significantly influenced by subducted slab materials, display higher oxidation states than most of their thicker crust counterparts. These findings suggest that both subduction dynamics and crustal thickness play a vital role in determining the oxidation state of arc magmas and, consequently, their capacity to generate PCDs. Highly oxidized, primitive arc magmas are less favorable for PCD formation due to that they tend to experience magnetite fractionation and thus sulfide saturation in the early stage of magma evolution, a process leading to copper depletion. On the contra

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A review of polybrominated diphenyl ethers and alternative brominated flame retardants in wildlife from China:Levels,trends,and bioaccumulation characteristics

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Journal of Environmental Sciences 2012年第2期24卷 183-194页

作者： Jiangping Wu Ying Zhang Xiaojun Luo Yazhe She Lehuan Yu Shejun Chen Bixian Mai State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China. Graduate University of the Chinese Academy of Sciences Beijing 100049 China

Accelerated industrialization and urbanization,and unregulated disposal of waste of electric and electronic equipment（e-waste） in China have caused environmental pollution of brominated flame retardants（BFRs）.This review summarized the levels,trends,and bioaccumulation characteristics of polybrominated diphenyl ethers（PBDEs） and other potential alternative BFRs including hexabromocyclododecanes（HBCDs）,1,2-bis（2,4,6-dibromophenoxy） ethane（BTBPE） and decabromodiphenylethane（DBDPE） in wildlife from *** levels in wildlife from China were generally higher than those from other parts in Asia,and were comparable to those from Europe but were lower than those from North ***,wildlife from the e-waste recycling sites in South China and East China contained much higher PBDEs compared to other reports around the world,suggesting the heavy contamination of PBDEs in these *** alternative BFRs were also detected in wildlife,revealing that the animals are exposed to these chemicals,in addition to *** trends indicated by levels in marine mammals from South China suggested that PBDE levels increased from the beginning of 1990s to 2000s,but decreased from the middle of 2000s,followed by relatively steady *** contrast,HBCDs were found to be continuously increasing from 1997 to 2007,indicating the increasing usage of HBCDs in China in recent *** to PBDE profiles found in other parts,aquatic species and birds from China contained relatively higher contributions of BDE28 and 209,respectively,suggesting the possible different usage pattern of *** works including keeping monitoring at a reasonable scale and frequency to make sure levels near urban centers indicative of population do not increase are ***,focus effort on e-waste recycling regions to look for impacts and to determine if regulation/controls are resulting in lower environmental contamination,and incorporation of sentinel species in monitoring efforts

关键词： brominated flame retardants polybrominated diphenyl ethers wildlife electronic waste China

Levels of synthetic musk fragrances in human milk from three cities in the Yangtze River Delta in Eastern China

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Journal of Environmental Sciences 2011年第6期23卷 983-990页

作者： Xiaolan Zhang Gaofeng Liang Xiangying Zeng Jing Zhou Guoying Sheng Jiamo Fu institute of Environmental Pollution and Health School of Environmental and Chemical Engineering Shanghai University Shanghai 200444 China State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China

Synthetic musks are used as additives in many household *** absorption into the human body,they accumulate and their concentrations in human milk reflect both the mother and her infant＇s exposure *** of four synthetic musks,musk xylene（1-tert-butyl-2,6-dimethyl-2,4,6-trinitrobenzene,MX）,musk ketone（4-tert-butyl-2,6-dimethyl-3,5-dinitroacetophenone,MK）,1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]-2-benzopyran（HHCB） and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4tetrahydronaphthalene（AHTN）,were determined in human milk samples collected from Shanghai,Wuxi,and Shaoxing in Eastern *** four synthetic musks were found in most samples analyzed,with HHCB the dominant component followed by *** median（mean） values for HHCB,AHTN,MX and MK concentrations were 63（82）,5（12）,17（24） and 4（9） ng/g lipid weight,*** data suggested the total synthetic musk contamination was low,and the distribution percentage was HHCB 〉 MX 〉 AHTN ≈ *** relative high ratio of nitro to polycylic musk indicated that nitro musks were still widely *** musk concentrations in these cities were not significantly different from each other（p 〉 0.05）.Principal components score plots were obtained,which showed similar exposure *** amount of total synthetic musks in human milk were not associated with mother＇s age,although HHCB was significantly correlated with AHTN（p 〈 0.05）.Daily ingestion of HHCB,AHTN,MX and MK for infants from human milk were estimated as（2526 ± 2926）,（370 ± 524）,（7391 ± 832）,and（277 ± 462） ng/day,*** doses were 1-2 orders of magnitude below the provisional tolerable daily intakes.

关键词： synthetic musks human milk exposure of infant

Xiuyan crater, China: Impact origin confirmed

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Chinese Science Bulletin 2010年第17期55卷 1777-1781页

作者： CHEN Ming XIAO WanSheng XIE XianDe TAN DaYong CAO YuBo guangzhou institute of geochemistry Chinese Academy of Sciences Guangzhou 510640 China

The well-preserved 1.8-km-diameter Xiuyan crater is located in the low mountain-hill region of the northern part of Liaodong Peninsula of northern China. Recently, a 307-m-deep borehole at the centre of crater became available. After penetrating 107 m lacustrine sediments, a breccia lens about 188 m in thickness was encountered. The crater-fill breccia is deposits of rock clasts and fragments more or less shock-metamorphosed. The features of geological structure and stratigraphic configuration within the crater, shock-melted rocks, and PDFs in quartz found in the basement rocks close to the crater rim and in the crater-fill breccia provide clear evidence for an impact origin of the Xiuyan crater.

关键词：陨石坑岫岩中国湖泊沉积物火山口角砾岩北部地区冲击变质

Redox processes in subduction zones:Progress and prospect

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Science China Earth Sciences 2020年第12期63卷 1952-1968页

作者： Jintuan Wang Xiaolin Xiong Yixiang Chen Fangfang Huang State Key Laboratory of Isotope geochemistry Guangzhou Institute of GeochemistryCASGuangzhou510640China School of Earth and Space Sciences University of Science and Technology of ChinaHefei230026China

Oxygen fugacity(fO_(2))is an intensive variable that describes the redox state of a *** controlling the valence state of multivalent elements,fO_(2)affects the stability of iron-bearing minerals,dominants the species of volatile elements(e.g.,carbon and sulfur),and controls the partitioning behaviors of multivalent elements(e.g.,iron,vanadium,cerium,europium).Thus,fO_(2)plays a key role in understanding the generation and differentiation of arc magmas,the formation of magmatic-hydrothermal deposits,and the nature of magmatic *** zones are an important site for arc magmatism and fluid action,and the study of redox processes is indispensable in subduction zone *** this paper,we first introduce the concept,expression,and estimation methods of fO_(2).Then we retrospect the history and progress about the oxidation state of the metasomatized mantle wedge,summarize the redox property of slab-derived fluids,and review the latest progress on redox evolution of arc magmas during magma generation and *** main conclusions include:(1)despite its wide variation range,fO_(2)of the mantle wedge is generally higher than that of the oceanic mantle;(2)the redox property of the subducting slab-derived fluids is still controversial and the mechanism for the oxidization of the mantle wedge remains unclear;(3)how the fO_(2)varies during the generation and differentiation of the arc magmas is *** propose that the crux in deciphering the oxidization mechanism of the mantle wedge is to determine the mobility of iron,carbon and sulfur in subducting slab-derived fluids(especially solute-rich fluid or supercritical fluid);the key in understanding the redox evolution during arc magma generation and differentiation is to determine the partition coefficients of Fe^(3+)and Fe^(2+)between ferromagnesian minerals and silicate melts.

关键词： Subduction zones Oxygen fugacity Mantle wedge Slab dehydration Arc magma differentiation

Higher pressure differentiation of arc magmas under thicker crust

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National Science Review 2023年第3期10卷 100-101页

作者： Yi-Gang Xu State Key Laboratory of Isotope geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Southern Marine Science and Engineering Guangdong Laboratory(guangzhou)

The formation of continental crust is pivotal to understanding the evolution of the earth and its *** average intermediate or’andesitic’bulk composition and characteristic depletion of niobium of the continental crust are strikingly matched by convergent margin magmas [1].This has led to the inference that most continental crust is derived from igneous,arc ***,continental crust has characteristically higher Mg#(>0.5) than most oceanic arc andesites (<0.5).

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Main controlling factors and enrichment area evaluation of shale gas of the Lower Paleozoic marine strata in south China

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Petroleum Science 2015年第4期12卷 573-586页

作者： Xian-Ming Xiao Qiang Wei Hai-Feng Gai Teng-Fei Li Mao-Lin Wang Lei Pan Ji Chen Hui Tian State Key Laboratory of Organic geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The Lower Paleozoic shale in south China has a very high maturity and experienced strong tectonic defor- mation. This character is quite different from the North America shale and has inhibited the shale gas evaluation and exploration in this area. The present paper reports a com- prehensive investigation of maturity, reservoir properties, fluid pressure, gas content, preservation conditions, and other relevant aspects of the Lower Paleozoic shale from the Sichuan Basin and its surrounding areas. It is found that within the main maturity range （2.5 % 〈 EqRo 〈 3.5 %） of the shale, its porosity develops well, having a positive cor- relation with the TOC content, and its gas content is con- trolled mainly by the preservation conditions related to the tectonic deformation, but shale with a super high maturity （EqRo 〉 3.5 %） is considered a high risk for shale gas exploration. Taking the southern area of the Sichuan Basin and the southeastern area of Chongqing as examples of uplifted/folded and faulted/folded areas, respectively, geo- logical models of shale gas content and loss were proposed. For the uplifted/folded area with a simple tectonic defor- mation, the shale system （with a depth 〉 2000 m） has lar- gely retained overpressure during uplifting without a great loss of gas, and an industrial shale gas potential is generally possible. However, for the faulted/folded area with a strong tectonic deformation, the sealing condition of the shale system was usually destroyed to a certain degree with a great loss of free gas, which decreased the pressure coefficient and resulted in a low production capacity. It is predicted that the deeply buried shale （〉3000 m） has a greater gas potential and will become the focus for further exploration and development in most of the south China region （outside the Sichuan Basin）.

关键词： Lower Paleozoic shale gas Maturity Maincontrolling factors Tectonic deformation