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Mobility of rhenium and selenium during chemical weathering and their implication for petrogenic organic carbon oxidation

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Science China Earth Sciences 2024年第3期67卷 740-750页

作者： Yuhong ZHANG jin WANG Yuanxin QU Chao ZHU zhangdong jin State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China University of Chinese Academy of Sciences Beijing 100049China Xi'an Institute for Innovative Earth Environment Research Xi'an 710061China Institute of Global Environmental Change Xi'an Jiaotong UniversityXi'an 710049China

The oxidative weathering of petrogenic organic carbon(OC_(petro)) is an important source of carbon dioxide(CO_(2)) into the atmosphere on geological timescales and significantly influences the carbon cycle and global climate change. However, at present, a robust proxy to assess OC_(petro)oxidation is lacking. Riverine rhenium(Re) has emerged as a potential proxy to trace OC_(petro)oxidation, but little is known about Re sources and its relationship with OC_(petro)oxidation. To better understand the robustness of this proxy, we analyzed a shale weathering profile from the early Cambrian Shuijingtuo Formation in Chengkou County, Chongqing City, to address the mobility of Re and selenium(Se) and their relationship with the oxidation of OC_(petro)by analyses of the elemental variation and sequential extraction. The results showed that the chemical index of alteration(CIA)increases from the fresh bedrock to the weathered sections, indicating enhanced weathering intensity. Based on the sequential extraction and mass transfer coefficients(τ), Re and Se mainly exist in the organic phase of shale and are paired lost with OC_(petro) during weathering, with no obvious correlation with sulfide minerals. Furthermore, the different proportions of Re and Se loss with OC_(petro) loss can be attributed to their different geochemical behaviors during weathering. Our study supports Re as a robust proxy to trace OC_(petro) oxidation, whereas Se is the potential one. In the future, combined studies on various sedimentary rock profiles with catchment basins are needed to determine the sources of riverine Re and Se and their relationships with OC_(petro) oxidation.

关键词： Rhenium and selenium Shale Mobility OC_(petro) Chemical weathering

Mineralogy of the otoliths of naked carp Gymnocypris przewalskii (Kessler) from Lake Qinghai and its Sr/Ca potential implications for migratory pattern

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Science China Earth Sciences 2012年第6期55卷 983-990页

作者： ZHOU Ling jin zhangdong LI FuChun State Key Laboratory of＇Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi＇an 710075 China Graduate University of Chinese Academy of Sciences Beijing 100049 China College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing 210095 China

Otoliths are biogenic carbonate minerals whose microstructure and microchemistry have been used for age determination, stock identification, life history and environmental tracing. Using X-ray diffraction （XRD） and Fourier transform infrared （FTIR） spectroscopy, we have determined the mineral types and crystalline characteristics of three pairs of otoliths from naked carp Gymnocypris przewalskii, the predominant fish in Lake Qinghai. The results indicate that the mineral of both lapillus and sagitta of the naked carp is aragonite, and that of asteriscus is vaterite. The aragonite of lapillus has prefect crystallization. Given the shape of lapillus and the sensitivity of its aragonite to water chemistry, lapillus was used to analyze temporal Sr/Ca ratios along the maximal growth axis by an electron probe microanalyzer （EPMA）. Consistent variations of Sr/Ca ratios with a range of 1.0x10-3-5.0~10-3 on the long and short radii indicate that Sr/Ca ratios of lapillus potentially respond to the chemical compositions of the host waters during the period of the naked carp＇s growth and migration. Discontinuous （dark） zones of lapillus were formed during fall and winter when the naked carp grows slowly in Lake Qinghai, resulting in similar low Sr/Ca ratios to lake water, whereas incremental zones with higher St/Ca ratios respond to its migratory river waters during spring and summer. Various Sr/Ca ratios of incremental zones suggest that the migratory pattern of the naked carp may be much more flexible, rather than in a single river. Therefore, high-resolution otolith microchemistry of the naked carp can be used to trace its migratory behavior, which is of significance for determining its migratory pattern and life history of this precious species inhabiting the Tibetan Plateau.

关键词： Lake Qinghai naked carp otolith migration aragonite Sr/Ca ratio environmental tracer

Chemical weathering processes in the Chinese Loess Plateau

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Geoscience Frontiers 2024年第5期15卷 197-209页

作者： Ningpan Chai Zhiqi Zhao Xiaoke Li Jun Xiao zhangdong jin School of Earth Science and Resources Chang’an UniversityXi’an 710054China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Xi’an Institute for Innovative Earth Environment Research Xi’an 710061China

Covered by erodible loess and affected by significant seasonal climate variations,chemical weathering in the Chinese Loess Plateau(abbreviated as CLP)has important effects on the hydrochemistry of the Yellow River and the global carbon ***,chemical weathering processes in the CLP are still *** on 296 river water samples in the CLP in the different seasons,hydrochemistry,weathering processes,and their controlling factors were *** waters in the CLP exhibited slightly alkalinity(pH=8.4±0.5)with much high total dissolved solids(TDS)values(691±813 mg/L).The water types of river water in the CLP were primarily SO_(4)^(2-)-Cl^(-)-Na^(+),HCO_(3)^(-)-Ca^(2+)-Mg^(2+),and SO_(4)^(2-)-Cl^(-)-Ca^(2+)-Mg^(2+).According to the forward model,evaporite dissolution has the largest contribution(55.1%±0.2%)to riverine solutes in the CLP,then followed by carbonate weathering(35.6%±0.2%)and silicate weathering(6.5%±0.1%).For spatio-temporal variations,the contribution of evaporite dissolution in the CLP decreased from northwest to southeast with higher proportion in the dry season,carbonate weathering increased from northwest to southeast with a higher proportion in the wet season,and silicate weathering showed minor spatio-temporal ***^(2+)and Mg^(2+)were affected by carbonate precipitation and/or incongruent calcite dissolution,and about 50%of samples exhibited cation exchange *** physical erosion rate in the CLP,which was 372±293 t·km^(-2)·yr^(-1),varied greatly and was greater than those of other worldwide *** weathering rates in the CLP showed an increasing trend *** the wet season,high runoff led to the release of evaporite and carbonate from loess,while the interfacial reaction kinetic limited the increase of the silicate weathering *** CO_(2)consumption budget by carbonate weathering(6.1×10^(10)mol/yr)and silicate weathering(1.6×10^(10)mol/yr)in the CLP accounted for 0.29%and 0.08%of the global carb

关键词： Chemical weathering Chinese Loess Plateau Spatio-temporal variations CO_(2)budget Physical erosion

Origin of Li-F-rich granite: Evidence from high P-T experiments

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Science China Earth Sciences 2004年第7期47卷 639-650页

作者： LI Fuchun ZHU jinchu RAO Bing jin zhangdong ZHANG Linsong School of Resource and Environment Sciences Nanjing Agriculture UniversityNanjing 210095China State Key Laboratory for Mineral Deposits Research Nanjing UniversityNanjing 210093China Nanjing Institute of Geography and Limnology Chinese Academy of SciencesNanjing 210008China

Though magmatic origin of Li-F-rich granite has been supported effectively by the existence of volcanic and subvolcanic rocks and melt inclusions trapped in them with similar chemical compositions, evidence from high T-P experiments is poor up to now. To simulate the evolution process of Li-F-rich granite and to interpret its forming mechanism, a series of melting-crystallization experiments were carried out. Under the conditions of 1×108 Pa and 570–700°C, a magmatic mineral association of quartz + alkali feldspar + lithium muscovite/ferromuscovite ± fluorite ± cassiterite is found in leucogranite-HF-H2O system. This indicates the following points: (i) Fluorite, light-colored muscovite and cassiterite can crystallize directly from the Li-F-rich granitic melt. (ii) The coexistence of dark-colored micas (e.g. biotite) and light-colored micas (e.g. lithium muscovite and ferromuscovite) suggests that the muscovite granite and two-mica granite can be formed under magmatic condition. The zonal texture of micas is not the sole feature for the micas of hydrothermal origin. (iii) As crystallization proceeds, the SiO2 concentration of the residual melt decreases, while the Al2O3 and F concentrations and A/CNK, NKA/Si ratios of the melt incerese, favoring the formation of Li-F-rich granites. Our experiment results are well consistent with the vertical zonation widely observed in rare metal bearing granites, and therefore provide strong experimental evidence for magmatic origin of Li-F-rich granite.

关键词： fluorite lithium muscovite ferromuscovite cassiterite melt evolution Li-F-rich granite high P-T experiment DOI: 10.1360/03yd0339

Sm-Nd isotope study and dating on Honguleleng ophiolite in Xinjiang, China

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Chinese Science Bulletin 1999年第20期44卷 1914-1917页

作者： zhangdong jin Jianhua Huang Fuchun Li Nanjing Univ State Key Lab Res Mineral Deposits Nanjing 210093 Peoples R China

A study of the Sm-Nd isotope composition of Honguleleng ophiolite in Xinjiang, China, isochron age ((626±25)Ma),εNd(t) = 8.40,and its model age (TNdDM) in the range of 1 180-1 208 Ma, indicates that the ophiolite was formed in the late stage of the Upper Sinian. In combination with its facies association, petrochemistry, REE patterns, trace elements

关键词： ophiolite Sm-Nd isochron age Honguleleng Xinjiang.

Characteristics of an early Holocene climate and environment from lake sediments in Ebinur region, NW China

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Science China Earth Sciences 2005年第2期48卷 258-265页

作者： WU jinglu SHEN Ji WANG Sumin jin zhangdong YANG Xiangdong Nanjing Institute of Geography & Limnology Chinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China Nanjing Institute of Geography & LimnologyChinese Academy of SciencesNanjing210008China

The characteristics of climatic environment in the early Holocene epoch were studied through analyzing environmental proxies from the sediments in the Ebinur Lake--a closed one in the arid region. The pollen assemblage and other geochemical indices showed that, the temperature was somewhat low in the period (8.0-11.5 cal kaBP) as a whole, but in the early period (11.5-10.6 cal kaBP) the temperature was higher, in company with more precipitation. In the conversion period from the early Holocene epoch to the middle Holocene epoch (8.9-8.0 cal kaBP) the climate fluctuated remarkably. Particularly the three layers of peat sediment revealed the strong instability of climate in the early Holocene epoch in the Ebinur region. All information on the development of peat and the experimental data of pollen and stable isotopes implied that, the climatic condition at 8.2, 8.6 and 10.5 cal kaBP was characterized by noticeable cold and humidness, and could be regarded as three cold and humid events in the early Holocene epoch.

关键词： early Holocene epoch, climatic evolution, pollen assemblege, stable isotopic record, Ebinur Lake.

Fingerprinting hydrothermal fluids in porphyry Cu deposits using K and Mg isotopes

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Science China Earth Sciences 2020年第1期63卷 108-120页

作者： Weiqiang LI Shugao ZHAO Xiaomin WANG Shilei LI Guoguang WANG Tao YANG zhangdong jin State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjing 210046China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710061China

In this study, we performed an integrated investigation of K and Mg isotopes in hydrothermally altered rocks from the giant Dexing porphyry Cu deposit in China. Both the altered porphyry intrusion and the surrounding wall rocks exhibit large variations in K and Mg isotope compositions, with δ41K values ranging between-1.02‰ and 0.38‰, and δ26Mg values ranging between-0.49‰ and 0.32‰. The δ41K and δ26Mg values of the majority of altered samples are higher than the isotopic baseline values for upper continental crust. We attribute the general increase in δ41 K and δ26Mg in altered rocks to hydrothermal alteration,which caused preferential incorporation of heavy K and Mg isotopes in alteration products, particularly phyllosilicates. However,a few altered samples show anomalously low δ41K and δ26Mg values. The δ41K and δ26Mg values do not correlate with K and Mg concentrations, or mineralogy of altered samples. The variable K-Mg isotope data likely reflect fluids of different physicalchemical properties, or different isotopic compositions. Based on the combined K-Mg isotope data, at least three groups of hydrothermal fluids are distinguished from the Dexing porphyry deposit. Therefore, K-Mg isotopes are potentially a novel tracer for fingerprinting fluids in complex hydrothermal systems.

关键词： hydrothermal isotope alteration

The role of earthquake-induced landslides in erosion and weathering from active mountain ranges:Progress and perspectives

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Science China Earth Sciences 2021年第12期64卷 2069-2082页

作者： zhangdong jin Robert G.HILTON AJoshua WEST Gen K.LI Fei ZHANG jin WANG Gaojun LI Xuanmei FAN Meng-Long HSIEH State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China Institute of Global Environmental Change Xi’an Jiaotong UniversityXi’an710049China Department of Geography Durham UniversityDurhamDH13LEUK Department of Earth Sciences University of Southern CaliforniaLos AngelesCA90089USA Division of Geological and Planetary Sciences California Institute of TechnologyPasadenaCA91125USA School of Land Engineering Chang’an UniversityXi’an710054China Department of Earth and Planetary Sciences Nanjing UniversityNanjing210023China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China Department of Earth and Environmental Sciences Taiwan Chung Cheng UniversityChiayi600China

Earthquakes play a fundamental role in the evolution of Earth’s topography through co-seismic uplift and subsidence,as well as erosion through widespread landslides induced by ground ***-induced landslides can result in exceptional increases in the transfer of mass from landscapes,supplying sediment to rivers where impacts can last for decades or *** can also erode vegetation and soils,in addition to exposing freshly ground rock mass,which can both result in regionally significant carbon *** work has sought to quantify the fluxes,rates,and temporal patterns of the impacts on earth surface processes generated by these tectonic *** this review,we focus on the impacts of earthquake-induced landslides on erosion and sediment flux,river water chemistry,and carbon export through the lens of the well-studied 2008 Wenchuan *** then discuss these themes in the context of works from the 1999 Taiwan Chi-Chi earthquake,2015 Nepalese Gorkha earthquake,and New Zealand historical earthquakes,altogether highlighting an important role of earthquake-induced landslides in erosion and weathering along tectonically active mountain *** suggest that more monitoring,geochemical tracing,paleo-records,and/or modelling studies are needed to compare the processes and fluxes of catchment erosion and weathering before and after earthquake events,which will help to deepen our understanding not only of the impacts of earthquake-induced landslides on earth surface processes,but also the linkage among high magnitude events,continental erosion and weathering,and the long-term global carbon cycle.

关键词： Earthquake Erosion Chemical weathering The carbon cycle Tectonically active mountain ranges

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Experimental study on crystallization kinetics of alkali feldspar under high T-P conditions

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Chinese Science Bulletin 2000年第22期45卷 2096-2100页

作者： LI Fuchun ZHU jinchu RAO Bing LAI Mingyuan jin zhangdong Department of Earth Sciences and State Key Laboratory for Research of Mineral Deposits Nanjing UniversityNanjing 210093China

In the granite-NaF-H2O system, there exists a nucleation lag in the course of alkali feldspar crystallization indicated by experiments on crystallization kinetics. The nucleation lag time is about 18 h at 700℃ and about 6 h at 650℃.nucleation rate and crystal-growth rate of alkali feldspar are not constant during the crystallization process, but vary with crystallization time. Here we suggest that the lag time should be taken into account in the calculation formula of nucleation rate and crystal-growth rate to obtain more reliable parameters.

关键词： alkali feldspar nucleation density nucleation lag nucleation rate crystal-growth rate.