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Spatiotemporal evolution of carbon sequestration of limestone weathering in China

Science China Earth Sciences 2019年第6期62卷 974-991页

作者： Huiwen LI Shijie WANG Xiaoyong BAI Yue CAO Luhua WU State Key Laboratory of Environmental geochemistry Institute of Geochemistry Chinese Academy of Sciences Puding Comprehensive Karst Research and Experimental Station Institute of Geochemistry Chinese Academy of Sciences and Science and Technology Department of Guizhou Province University of Chinese Academy of Sciences

Carbonate carbon sequestration(CS) can aid in solving the problem of terrestrial residual carbon sinks and imbalances in the global carbon budget. Thus, complete understanding of the magnitude, spatiotemporal distribution, and evolution of this sequestration is highly desirable. On the basis of random forest regression and maximal potential dissolution model for carbonate, we estimated the CS of typical carbonate weathering in China from 2000 to 2014, that is, the sequestration of limestone weathering, using long-term ecologic, meteorological, hydrological raster data, and monitored data from 44 watersheds in China and surrounding regions. We extended our analyses by systematically exploring the spatiotemporal pattern and evolution trend of the flux and total sequestration. High levels of ionic activity coefficients of Ca^(2+) and HCO_3^- in limestone regions were observed to be mainly distributed in Northern and Northwestern China with a clear gradient from northwest to southeast. With a contrary spatial pattern, the annual average CS flux(CSF) of limestone weathering in China was estimated to be 4.28 t C km^(-2) yr^(-1), with high values mainly in the karst zones in Southeastern China. The mean CSF in different latitudes showed that Southern China(south of 28.14°N) was the region with the largest interannual fluctuation of flux and CSF increases as latitude decreases. The mean CSF in subtropical and tropical(TR) regions was the maximum of all major climate types, and for the frigid(F), mid-temperate(MTE), warm temperate(WTE), and temperate(TE) major climates; the CSF in the desert(D)subdivided climate was the minimum of these climates. By contrast, the values in grassland(G) and broad-leaved forest subdivided climate were the maximum. The pixel-based trend analysis indicated that the CSF of limestone weathering in China was slightly increasing in the period 2000–2014 with a rate of 0.036 t C km^(-2) yr^(-1). Furthermore, the annual total CS was estimated to be 7.0

关键词： Limestone Chemical weathering carbon sink Spatiotemporal evolution Dissolution Random forest

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REE Characteristics of a New Uranium Mineral from the Xianshi Uranium Deposit, South China

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Acta Geologica Sinica(English Edition) 2018年第4期92卷 1667-1669页

作者： LUO Jincheng HU Ruizhong BI Xianwu CHEN Youwei State Key Laboratory of Ore Deposit geochemistry Institute of Geochemistry Chinese Academy of Sciences department of Geological Sciences University of Manitoba

Objective Galuskin et al. （2011） firstly discovered that vorlanite （CaU^6＋/4＋）04 is a rare Ca-rich mineral with a fluorite-type structure, which is isostructural with uraninite （U^4＋O2）. Previous studies of the Xianshi granite-related uranium deposit reported that uraninite and pyrite are the major ore minerals whereas galena, clausthalite （PbSe）, and pyrite are minor phases in the ores. A more detailed petrographic and geochronological study of the uranium minerals from the Xianshi deposit showed that there are three distinct types of uraninite-bearing assemblages which formed at three mineralization episodes （Fig. la; Luo et al., 2015）.

关键词： REE Characteristics of a New Uranium Mineral from the Xianshi Uranium Deposit Ca South China

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SILURIAN-DEVONIAN COUPLING OF THE NORTH CHINA AND YANGTZE PLATES: EVIDENCE FROM THE geochemistry OF SEDIMENTARY ROCKS

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Science China Chemistry 1991年第11期34卷 1372-1380页

作者：高山张本仁谷晓明谢千里郭孝明 department of geochemistry China University of Geosciences Wuhan 430074 PRC

Major and trace element compositions of a large number of Proterozoic-Tertiary finegrained clastic sedimentary rocks from the Qinling Orogenic Belt and its adjacent southern margin of the North China Platform and northern margin of the Yangtze Platform reveal that the North China and Yangtze plates were coupled during the period of Silurian to Devonian.

关键词： Qinling Orogenic Belt North China plate Yangtze plate Silurian-Devonian continental coupling geochemistry of fine-grained elastic sedimentary rocks.

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Surface radioactive anomalies at Srisailam sub basin,Cuddapah basin,India

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Chinese Journal Of geochemistry 2015年第2期34卷 265-271页

作者： Vishnu Bhoopathi S.Niranjan Kumar R.S.N.Sastry B.Srinivas department of Applied geochemistry Osmania University Atomic Mineral Directorate for Exploration and Research

Surface radioactive survey has been carried with portable gamma ray spectrometer(PGRS) about the 45 km2 around the Srisailam sub basin,the surface radioactive anomalies were found at Chennakesavula gutta in the Srisailam sub basin of Cuddapah basin in the age of meso-neo proterozoic,*** integrated geochemical and radiometric surveys were conducted as part of research work in the Srisailam basin,it has resulted the locating of surface radioactive anomalies near the Chennakesavula *** uranium minerals are observed along with the fracture planes in the Archean basement granite in the proximity of unconformity contact of Srisailam *** granite underlies the Srisailam formation and forms the source for possible unconformity related uranium mineralisation in the Srisailam sub-basin evidence by the significant radioactive *** radioactivity recorded by PGRS reflected uraniferous nature of the radioactivity(Average total counts =195 ppm;U = 202 ppm;Th =22ppm;%K = 4.1,n = 15).

关键词：放射性异常表面印度分盆 γ射线谱仪放射性调查 m盆地地球化学

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He,Ne and Ar isotopic composition of Fe-Mn crusts from the western and central Pacific Ocean and implications for their genesis

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Science China Earth Sciences 2007年第6期50卷 857-868页

作者： G. P. GLASBY department of geochemistry GZG Goldschmidtstrasse 1 D-37077 Gttingen Germany

The noble gas nuclide abundances and isotopic ratios of the upmost layer of Fe-Mn crusts from the western and central Pacific Ocean have been determined. The results indicate that the He and Ar nuclide abundances and isotopic ratios can be classified into two types: low 3He/4He type and high 3He/4He type. The low 3He/4He type is characterized by high 4He abundances of 191×10?9 cm3·STP·g?1 on average, with variable 4He, 20Ne and 40Ar abundances in the range (42.8?421)×10?9 cm3·STP·g?1, (5.40?141)×10?9 cm3·STP·g?1, and (773?10976)×10?9 cm3·STP·g?1, respectively. The high 3He/4He samples are characterized by low 4He abundances of 11.7×10?9 cm3·STP·g?1 on average, with 4He, 20Ne and 40Ar abundances in the range of (7.57?17.4)×10?9 cm3·STP·g?1, (10.4?25.5)×10?1 cm3·STP·g?1 and (5354?9050)×10?9 cm3·STP·g?1, respectively. The low 3He/4He samples have 3He/4He ratios (with R/RA ratios of 2.04?2.92) which are lower than those of MORB (R/R A=8±1) and 40Ar/36Ar ratios (447?543) which are higher than those of air (295.5). The high 3He/4He samples have 3He/4He ratios (with R/R A ratios of 10.4?12.0) slightly higher than those of MORB (R/R A=8±1) and 40Ar/36Ar ratios (293?299) very similar to those of air (295.5). The Ne isotopic ratios (20Ne/22Ne and 21Ne/22Ne ratios of 10.3?10.9 and 0.02774?0.03039, respectively) and the 38Ar/36Ar ratios (0.1886?0.1963) have narrow ranges which are very similar to those of air (the 20Ne/22Ne, 21Ne/22Ne, 38Ar/36Ar ratios of 9.80, 0.029 and 0.187, respectively), and cannot be differentiated into different groups. The noble gas nuclide abundances and isotopic ratios, together with their regional variability, suggest that the noble gases in the Fe-Mn crusts originate primarily from the lower mantle. The low 3He/4He type and high 3He/4He type samples have noble gas characteristics similar to those of HIMU (High U/Pb Mantle)-and EM (Enriched Mantle)-type mantle material, respectively. The low 3He/4He type samples with HIMU-type noble gas isotopic rati

关键词： Fe-Mn crusts noble gases isotope geochemistry mantle heterogeneity Pacific Ocean

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Evolution of isotopic composition and deuterium excess of brines in the Sichuan Basin, China

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Chinese Journal Of geochemistry 2013年第1期32卷 69-77页

作者： YAN Qiushi GAO Zhiyou NI Shijun SHI Zeming YIN Guan geochemistry department College of Nuclear Technology and Automatic Engineering Chengdu University of Technology

The isotopic composition and parameters for deuterium excess of brines, which were sampled in the Si-chuan Basin, show obvious regularities of distribution. The brine isotopic composition shows distinct two systems of marine and terrestrial deposits, with the Middle Triassic strata as the boundary. Brine hydrogen isotopic composition of marine deposits is lower while oxygen isotopic composition is higher than that of the SMOW, respectively, indicating that the brines were derived from seawater with different evaporating degrees at different times. From the Sinian strata, up to the Cambrian, Permian Maokou Formation and the Triassic Jialingjiang Formation, the δD values of brines tend to become relatively positive with the strata becoming younger. Brines of terrestrial deposits are considered to have been derived from precipitation and their isotopic composition is close to the globe meteoric water line (GMWL). Brines of transitional deposits between marine and terrestrial ones (the Upper Triassic Xujiahe Formation) have δD and δ18O values falling between the two end members of marine deposit brines and precipitation, indicating that the brines are a mixture of precipitation and vaporing seawater. Water samples from the brine-bearing strata of different ages show various deuterium excesses (d) with an evident decreasing trend as the age of strata gets older and older. Brine-bearing strata of the Triassic Leikoupo-Jialingjiang Formation, the Permian Maokou Formation, the Cambrian and Sinian strata are all carbonate rocks which have experienced intensive water/rock reaction and the deuterium excess essentially changes with time. All brine-bearing-strata surrounding the basin or faults, as well as those brine wells exploited for resources, have been obviously influenced by the precipitation supply. Therefore, the deuterium excesses of their brines have increased to different extents, depending on the amount of involvement of meteoric water. The variation and distributio

关键词：同位素组成四川盆地过量氘卤水震旦纪地层演变中国陆相沉积

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Time Scale of Partial Melting of KLB-1 Peridotite: Constrained from Experimental Observation and Thermodynamic Models

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Journal of Earth Science 2018年第2期29卷 245-254页

作者： Wei Du Li Li Donald J.Weidner State Key Laboratory of Ore Deposit geochemistry Institute of Geochemistry Chinese Academy of Sciences Mineral Physics Institute Department of Geosciences University of New York at Stony Brook

Partial melting experiments were carried on KLB-1 peridotite, a xenolith sample from the Earth＇s upper mantle, at 1.5 GPa and temperatures from 1 300 to 1 600 ℃, with heating time varies from 1 to 30 min. We quantify the axial temperature gradient in the deformation-DIA appa- ratus （D-DIA） and constrain the time scale of partial melting by comparing experimental observa- tions with calculated result from pMELTS program. The compositions of the liquid phase and the coexisting solid phases （clinopyroxene, orthopyroxene, and olivine） agree well with those calculated from pMELTS program, suggesting that local chemical equilibrium achieves during partial melting, although longer heating time is required to homogenize the bulk sample. The Mg# （=Mg/（Mg＋Fe） moi.%） of olivines from the 1-minute heating experiment changed continuously along the axial of the graphite capsule. A thermal gradient of 50 ℃/mm was calculated by comparing the Mg# of oli- vine grains with the output of pMELTS program. Olivine grains at the hot end of the graphite cap- sule from the three experiments heated at 1 400 ℃ but with different annealing time show consis- tence on Mg#, indicating that partitioning of Fe2＋ between the olivine grains and the silicate melt happened fast, and partial melting occurs in seconds.

关键词： peridotite partial melting temperature gradient pMELTS program.

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The metallogenic mechanism of the sandstone-type copper deposits in the Chuxiong Basin, Yunnan Province

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Science China Earth Sciences 2000年第S1期43卷 262-272页

作者：陈根文夏斌吴延之涂光炽喻亨祥 Guangzhou Institute of geochemistry Chinese Academy of Sciences Guangzhou 510640 China Open Lab of Ore Deposit geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China department of Geology Central-South University of Technology Changsha 410083 China

The sandstone-type Cu deposits in the Chuxiong Basin occur in the Cretaceous Gaofengsi Formation and the Maotoushan Formation and the orebodies are stratoid and lenticular in form, structurally controlled by their stratigraphical position. Ore structures are dominated by impregnated and striped ones. In addition, it has been observed that copper mineralization is controlled by water-discharge and deformation structures. Orebodies are commonly seen on the gently inclined limbs of the anticline, with the involution front. Copper mineralization shows a distinct zonation. S, Pb isotope and REE data suggest that the copper would stem from the country rocks and the sulfur largely from the lower strata. During diagenesis oxidized Cu-bearing brines derived from the upper parts and reduced brines from the lower parts are involved in metallogenetic reactions in the stress neutral plane, which is the key to the formation of copper deposits in the Chuxiong Basin.

关键词： Chuxiong Basin Cretaceous standstone-type copper deposit metallogenic mechanism.

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Retrograde metamorphism of the eclogite in North Qaidam,western China:Constraints by joint ^(40)Ar/^(39)Ar in vacuo crushing and stepped heating

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Geoscience Frontiers 2015年第5期6卷 759-770页

作者： Rongguo Hu Jan Wijbrans Fraukje Brouwer Linghao Zhao Min Wang Huaning Qiu State Key Laboratory of Isotope geochemistry Guangzhou Institute of GeochemistryChinese Academy of Sciences department of Earth Sciences VU University Amsterdam University of Chinese Academy of Sciences

Two amphiboles and a syn-metamorphic quartz vein from the Yuka terrane,North Qaidam,western China,have been analyzed by joint40Ar/39Ar crushing in vacuo and stepwise heating *** crushing in vacuo results provide information to directly constrain the timing of fluid activity and the age of amphibolite-facies *** stepwise heating results could further be used to decipher the thermal history of the UHP *** from amphibolites and quartz vein within garnetamphibolite lens analyzed by in vacuo crushing yield similarly shaped age spectra and exhibit relatively flat age plateaus for the last several *** characteristics of gas release patterns and geochronological data testify to the presence of significant excess40Ar within the fluid *** age plateaux with weighted mean ages（WMA） ranges from 488 to 476 Ma for amphiboles and 403 Ma for quartz（2σ）.These data points constitute amphibole WMA yielding excellent isochrons with isochron ages of 469 and 463 Ma with initial40Ar/36Ar ratios of 520 and 334,*** isochron ages are interpreted to represent initial amphibolite-facies *** data points constituting the quartz age plateaux give an isochron age of 405 Ma with initial40Ar/36Ar ratio of 295,recording a significant aqueous fluid flow episode during the early *** spectra obtained by stepwise heating of amphibole residues remaining after crushing experiments are characterized by younger and relatively complex age spectra,which are probably influenced by the combined effects of resetting argon and/or mineral ***,we note that the spectra shapes have features in common:excluding the last two steps,minimum apparent ages are found at temperatures of around 500 ℃,corresponding to319 and 249 Ma,perhaps representing the time of isotopic resetting or resulting from release gas from mineral inclusions of,e.g.,biotite or *** apparent ages are obtained at temperatures of aro

关键词： 40Ar/39Ar techniques In vacuo crushing Amphibolite

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Distribution,fractionation,and contamination assessment of heavy metals in offshore surface sediments from western Xiamen Bay,China

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Acta Geochimica 2016年第4期35卷 355-367页

作者： Qiuli Yang Gongren Hu Ruilian Yu Haixing He Chengqi Lin department of Environmental Science and Engineering Huaqiao UniversityXiamenChina State Key Laboratory of Environmental geochemistry Institute of GeochemistryChinese Academy of Sciences Guiyang 550002China

Surface sediment samples were collected at 21 offshore sites in western Xiamen Bay, Southeast China. Total concentrations of Li, V, Cr, Co, Ni, Cu, Zn, St, Mn, Pb, Ba, Fe, and Ti were determined by inductively coupled plasma-optical emission spectrometry; Hg was determined by atomic fluorescence spectrometry. A modified BCR sequential extraction procedure was used to extract fractions of the above elements. Concentrations of Pb, Cr, and Hg at most sites met the primary standard criteria of Marine Sediment Quality except site S12 for Pb and S7 for Cr, while concentrations of Zn at 17 sites and Cu at seven sites exceeded the criteria. The mean concentration of Hg was three times higher than the background, with a possible source being the Jiulong River. Fe, Ti, Ba, Co, V, and Li dominated the residual phase, mainly from terrestrial input. Ni, Cr, Pb, and Hg in the non-residual phase varied largely between sites. Sr, Mn, Cu, and Zn were mainly in the non- residual fraction. Most sites showed considerable ecological risk; exceptions were site S7 （very high） and sites S10, S11, and S14 （moderate）. Cu showed moderate-to-high pollution and Pb exhibited no-to-low pollution, while other metals had a non-pollution status according to their ratios of secondary phase to primary phase （RSP）. Results of two assessment methods showed moderate pollution and a very high ecological risk for Cu, Zn, Ni, and Cr at site S7, which might be due to the local sewage treatment plant.

关键词： Heavy metal Fractionation - Assessment Sediments Distribution Western Xiamen Bay

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