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华南中生代陆内成矿作用

地学前缘 2024年第1期31卷 226-238页

作者：胡瑞忠高伟付山岭苏文超彭建堂毕献武中国科学院地球化学研究所矿床地球化学国家重点实验室贵州贵阳550081 中国科学院大学地球与行星科学学院北京100049

陆内成矿机制是全球性科学难题。华南陆块中生代成矿大爆发,成矿作用远离活动大陆边缘,形成西部金锑铅锌低温成矿省和东部钨锡多金属高温成矿省,是研究陆内成矿的理想场所。因为空间上的分离,两个成矿省长期被认为是互为独立的体系。研... 详细信息

陆内成矿机制是全球性科学难题。华南陆块中生代成矿大爆发,成矿作用远离活动大陆边缘,形成西部金锑铅锌低温成矿省和东部钨锡多金属高温成矿省,是研究陆内成矿的理想场所。因为空间上的分离,两个成矿省长期被认为是互为独立的体系。研究发现,西部低温成矿(230~200 Ma、160~130 Ma)与东部高温成矿时代一致并显示类似的地球化学指纹,印支期陆内造山和燕山期软流圈上涌是其共有成矿驱动机制,两个成矿省是具有成因联系的整体,共同构成面状展布的巨型多金属陆内成矿区;成矿后华南从西向东剥蚀程度的增强控制了目前近地表矿西部低温、东部高温的空间分布格局,低温成矿省东部区域的深部可能存在高温钨锡多金属矿床。在此基础上,建立了定位于陆内岩石圈先存薄弱区、陆壳供给矿源、高低温矿并重、成矿面状展布从而明显区别于板块边缘成矿机制的华南陆内成矿新理论。

关键词：华南陆块高温成矿省低温成矿省陆内成矿机制

Timing of Uranium Mineralization and Geological Implications of Shazijiang Granite-Hosted Uranium Deposit in Guangxi, South China: New Constraint from Chemical U-Pb Age

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Journal of Earth Science 2015年第6期26卷 911-919页

作者： Jincheng Luo ruizhong hu Shaohua Shi State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences hunan Institute of Geological Survey

Miaoershan（MES） uranium ore field is one of the most important uranium sources in China, hosts the largest Chanziping carbonaceous-siliceous-pelitic rock type uranium deposit in South China together with many other granite-hosted uranium deposits. The Shazijiang（SZJ） uranium deposit is one of the representative granite-hosted uranium deposits in the MES uranium ore field, situated in the Ziyuan, Guangxi Province, South China. Uranium mineralization in the SZJ deposit mainly occurs as uraninite with quartz and calcite veins that is spatially associated with mafic dykes in the region. The hydrothermal alteration includes silicification, carbonation and hematitization. New uraninite chemical U-Pb geochronology and petrographic evidences provide the timing constraints and new insights into the formation of the SZJ uranium deposit. The results show that the first stage of uranium mineralization formed at 97.5±4.0 Ma, whereas another stage of uranium mineralization occurred at 70.2±1.6 Ma. Two stages of uranium mineralization are fairly consistent with two episodic crustal extensions that occurred at -100 and -70 Ma throughout South China. This study indicates that there are two uranium mineralization events in SZJ uranium ore field controlled by mafic dyke, supporting that mafic dykes play an important topochemical role in uranium concentration and/or mobilization. Therefore, geochemical U-Pb age firstly reinforces that ore-forming age of the SZJ uranium deposit mainly yields at 97.5±4.0 and 70.2±1.6 Ma. Additionally, geochemical age method is particularly useful for interest samples which record information on multi-stage uranium mineralizations in South China.

关键词： Shazijiang uranium deposit uraninite U-Pb age EMPA uranium mineralization crustal extension South China.

Assessment of trace metals contamination in stream sediments and soils in Abuja leather mining, southwestern Nigeria

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Acta Geochimica 2018年第4期37卷 592-613页

作者： Abiola Oyebamiji Adegbola Odebunmi hu ruizhong Atta Rasool State Key Laboratory of Ore Deposit Geochemistry Instituteof Geochemistry Chinese Academy of SciencesGuiyang 550081 China Department of Geological Services Ogun State Ministry of Commerce and Industry Oke-Mosan Abeokuta Nigeria University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081 China Department of Science Laboratory Technology Ekiti StateUniversity Ado-Ekiti Ekiti State Nigeria

This study is aimed at determining the level of environmental degradation as well as the concentration of trace elements in soil and stream sediments in order to evaluate the environmental impact of the mining ***-five(25) soils and ten(10) stream sediment samples were collected from the study area. The physicochemical parameters were determined using appropriate instrumentation with the aid of a digital p H meter(Milwaukee meter) to measure the p H and electrical conductivity, total dissolved solids, moisture content and loss on ignition of the soil and stream sediment samples. The p H of the soil sample ranged from(6.10 to 7.19); Electrical conductivity ranged from(21.3 to 279.4 μS/cm), moisture content varied from(0.60% to 7.20%), and the LOI ranged from(2.03% to 18.62%). The results of the analysis showed that the concentrations of the trace elements in the soils and stream sediment samples were slightly higher than the background values. Plots of the trace elements in stream sediment samples show moderate, consistent decrease downstream except at points where there was mine water discharge into the main river. The pollution levels of heavy metals were examined in stream sediment and soil samples using different assessable indices, such as the enrichment factor, which showed significant-moderate enrichment for Cr, Th, Nb, Zn, Pb, Y and Zr and the geoaccumulation index, which showed practically moderate contamination with Cr, Ni and Sr based on regional background reference values. Geo-accumulation index and contamination index for soils and stream sediment revealed uncontaminated to moderate contamination. Likewise,elements with moderate contamination were Cr, Ni and *** Pearson correlation showed that there were significant positive associations among selected metals in soil and stream sediment samples.

关键词： Trace metals Stream sediments Geo-accumulation index - PCA Soil Southwestern Nigeria

Mineral Geochemical Compositions of Tourmalines and Their Significance in the Gejiu Tin Polymetallic Deposits, Yunnan, China

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Acta Geologica Sinica(English Edition) 2010年第1期84卷 155-166页

作者： JIA Runxing FANG Weixuan hu ruizhong State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang Guizhou 550002 China Beijing Institute of Geology for Mineral Resources Beijing 100012 China Beijing Donia Resources Co. Ltd. Beijing 100012 China

The Gejiu tin polymetallic deposits are located in the southeastern part of Yunnan Province in China. A detailed electronic microprobe study has been carried out to document geochemical compositions of tourmalines from the deposits. The results indicate a systematic change of mineral geochemical compositions, which might be used as a mineral geochemical tracer for post-magmatic hydrothermal fluid, basin fluid and their mixture. The tourmalines from granite are schori with Fe/ （Fe＋Mg） ratios of 0.912-1.00 and Na/（Na＋Ca） ratios of 0.892-0.981. Tourmalines as an inclusion in quartz from the ore bodies are dravite with Fe/（Fe＋Mg） ratios of 0.212-0.519 and Na/（Na＋Ca） ratios of 0.786--0.997. Tourmalines from the country rocks are dravite with Fe/（Fe＋Mg） ratios of 0.313--0.337 and Na/（Na＋Ca） ratio of 0.599-0.723. Tourmalines from cassiterite-tourmaline veins that occur in crannies within the country rocks show distinct optical zoning with alternate occurrence of dravite and schorl, Fe/（Fe＋Mg）=0.374-0.843, Na/（Na＋Ca）=0.538-0.987. It suggests that schorl in granite and dravite in carbonatite are related to magmatic fluid and basin fluid respectively. When magmatic fluid rose up and entered into crannies of the country rocks, consisting mainly of carbonatite, basin fluid would be constantly added to the magmatic fluid. The two types of fluid were mixed in structural crannies of the sedimentary basin accompanied with periodic geochemical oscillations to form material records in chemical composition zonings of tourmalines.

关键词： tourmaline mineral geochemical zoning geochemical oscillation tin polymetallic deposit,Gejiu

Geochemical Characteristics and Metallogenesis of the Qingkuangshan Ni-Cu-PGE Mineralized Mafic-Ultramafic Intrusion in huili County, Sichuan Province, SW China

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Acta Geologica Sinica(English Edition) 2012年第3期86卷 590-607页

作者： Zhu Feilin TAO Yan hu ruizhong MA Yansheng State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550002China Graduate University of the Chinese Academy of Sciences Beijing 100049China East China Geological Exploration Bureau of Nonferrous Metals Jiangsu ProvinceNanjing 210007China

The Qingkuangshan Ni-Cu-PGE deposit, located in the Xiaoguanhe region of huili County, Sichuan Province, is one of several Ni-Cu-PGE deposits in the Emeishan Large Igneous Province （ELIP）. The ore-bearing intrusion is a mafic-ultramafic body. This paper reports major elements, trace elements and platinum-group elements in different types of rocks and sulfide-mineralized samples in the intrusion. These data are used to evaluate the source mantle characteristics, the degree of mantle partial melting, the composition of parental magma and the ore-forming processes. The results show that Qingkuangshan intrusion is part of the ELIP. The rocks have trace element ratios similar to the coeval Emeishan basalts. The primitive mantle-normalized patterns of Ni-Cu-PGE have positive slopes, and the ratios of Pd/Ir are lower than 22. The PGE compositions of sulfide ores and associated rocks are characterized by Ru depletion. The PGE contents in bulk sulfides are slightly depleted relative to Ni and Cu, which is similar to the Yangliuping Ni-Cu-PGE deposit. The composition of the parental magma for the intrusion is estimated to contain about 14.65 wt% MgO, 48.66 wt% SiO2 and 15.48 wt% FeOt, and the degree of mantle partial melting is estimated to be about 20%. In comparison with other typical Ni-Cu-PGE deposits in the ELIP, the Qingkuangshan Ni-Cu-PGE deposit has lower PGE contents than the Jinbaoshan PGE deposit, but has higher PGE contents than the Limahe and Baimazhai Ni-Cu deposit, and has similar PGE contents to the Yangliuping Ni-Cu-PGE deposit. The moderate PGE depletions in the bulk sulfide of the Qingkuanghan deposit suggest that the parental magma of the host intrusion may have undergone minor sulfide segregation at depth. The mixing calculations suggests that an average of 10% crustal contamination in the magma, which may have been the main cause of sulfide saturation in the magma. We propose that sulfide segregation from a moderately PGE depleted magma took place prior

关键词： Magmatic sulfide deposit mafic-ultramafic intrusion PGE Qingkuangshan Emeishan Large Igneous Province

Tin partition behavior and implications for the Furong tin ore formation associated with peralkaline intrusive granite in hunan Province,China

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Acta Geochimica 2016年第2期35卷 138-147页

作者： Xiaoyan hu Xianwu Bi ruizhong hu Guosheng Cai Youwei Chen State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guizhou Bureau of Nonferrous Metal and Nuclear Industry Geological Exploration

Tin deposits are often closely associated with granitic intrusions. In this study, we analyzed tin partition coefficients between different fluids and melts(D)as well as various crystals and melts D(D)from the Furong tin deposit associated with the Qitianling A-type granite. Our experimental results indicate that tin partition behavior is affected by the chemical compositions of fluids, melts, and minerals. Tin is prone to partitioning into the residual magma in fractional crystallization or other differential magmatic processes if the magma originated from crustal sources with high alkali content, high volatile content, and low oxygen fugacity. Highly evolved residual peralkaline granitic magma enriched in tin can lead to tin mineralization in a later stage. Furthermore, the volatiles F and Cl in the magma play important roles in tin partitioning behavior. Low F contents in the melt phase and high Cl content in the aqueous fluid phase are favorable factors for tin partitioning in the aqueous fluid phase. High Cl content in the aqueous fluid catalyzes water–rock interaction and leads to the extraction of tin from tinbearing minerals. All these findings support a hydrothermal origin for the tin deposits. In light of the geotectonic setting, petrochemical characteristics, and mineralizing physicochemical conditions of the Furong tin deposit, it is inferred that the ore-forming fluid of the Furong tin ore deposit could have derived from the Qitianling peralkaline intrusion.

关键词： Tin Partition Peralkaline granite hunan Province

Germanium in Magnetite:A Preliminary Review

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Acta Geologica Sinica(English Edition) 2017年第2期91卷 711-726页

作者： MENG Yumiao hu ruizhong huANG Xiaowen GAO Jianfeng State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

Magnetite is a very common mineral in various types of iron deposits and some sulfide deposits. Recent studies have focused on the use of trace elements in magnetite to discriminate ore types or trace ore-forming process. Germanium is a disperse element in the crust, but sometimes is not rare in magnetite. Germanium in magnetite can be determined by laser ablation ICP-MS due to its low detection limit（0.0X ppm）. In this study, we summary the Ge data of magnetite from magmatic deposits, iron formations, skarn deposits, iron oxide copper-gold deposits, and igneous derived hydrothermal deposits. Magnetite from iron formations contains relatively high Ge（up to ~250 ppm）, whereas those from all other deposits mostly contains Ge less than 10 ppm, indicating that iron formations can be discriminated from other Fe deposits by Ge contents. Germanium in magmatic/hydrothermal magnetite is controlled by a few factors. Primary magma/fluid composition may be the major control of Ge in magnetite. Higher oxygen fugacity may be beneficial to Ge partition into magnetite. Sulfur fugacity and temperature may have little effect on Ge in magnetite. The enrichment mechanism of Ge in magnetite from iron formations remains unknown due to the complex ore genesis. Germanium along with other elements（Mn, Ni, Ga） and element ratios（Ge/Ga and Ge/Si raios） can distinguish different types of deposits, indicating that Ge can be used as a discriminate factor like Ti and V. Because of the availability of in situ analytical technique like laser ablation ICP-MS, in situ Ge/Si ratio of magnetite can serve as a geochemical tracer and may provide new constraints on the genesis of banded iron formations.

关键词： germanium magnetite controlling factor iron deposits discriminate factor

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

Mercury isotope constraints on the genesis of late Mesozoic Sb deposits in South China

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Science China Earth Sciences 2022年第2期65卷 269-281页

作者： Changzhou DENG Jiawei ZHANG ruizhong hu Kai LUO Yanan Zhu Runsheng YIN State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Guizhou Geological Survey Bureau of Geology and Mineral Exploration and Development of Guizhou ProvinceGuiyang 550081China Technology Innovation Center of Mineral Resources Exploration Engineering in Bedrock Zone Ministry of Natural ResourcesGuiyang 550081China College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China School of Earth Sciences Yunnan UniversityKunming 650500China

The late Mesozoic antimony(Sb)mineralization belt in South China hosts a large portion of the world’s Sb ***,the source and mineralization processes of these Sb deposits remain ***,we measured mercury(Hg)concentrations and isotopic compositions of stibnite in the Banpo Sb-only and Woxi Sbpolymetallic ore deposits,as well as associated rocks in the Yangtze Block in order to constrain the metal sources and ore formation processes in the South China Sb mineralization *** samples from both deposits exhibit significant enrichment in Hg(4.23–50.6 ppm)and have higher δ^(202)Hg values(−0.47‰to 2.03‰)than the studied Precambrian basement rocks(−1.42‰to 0.59‰),Paleozoic sedimentary rocks(−2.40‰to−0.32‰),and other natural Hg reserves(e.g.,marine and continental systems).This indicates that significant mass-dependent fractionation of Hg isotopes occurred during hydrothermal *** to slightly positive Δ^(199)Hg values of−0.17‰to 0.02‰were obtained for stibnite from the studied deposits,similar to values for the Precambrian basement rocks,but different from those of the Paleozoic sedimentary rocks and data previously reported for mantle *** suggests that Precambrian basement rocks were the source of Hg and associated *** data and the tectonic evolution of South China indicate that late Mesozoic asthenospheric upwelling,in response to the Paleo-Pacific oceanic slab foundering,generated heat that drove the circulation of fluids in the basement and crustal basinal *** fluids leached Sb,Hg,and other metals from the Precambrian basement rocks and formed the world-class Sb mineralization belt in South China.

关键词： Hg isotopes Mass-independent fractionation Sb deposits Metamorphic basement South China