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Integrated Stratigraphy and mineralogy of the Doushantuo Formation in Weng’an,South China,and Implications for Ediacaran Phosphogenesis

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Journal of Earth Science 2024年第2期35卷 476-503页

作者： Liangxuan Jiao Zhenbing She Dominic Papineau Yaguan Zhang Matthew S.Dodd Kenan Cao Qun Chen Guoyong Chen State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan430078China School of Earth Sciences China University of GeosciencesWuhan430047China London Centre for Nanotechnology University College London17-19 Gordon StreetLondonWC1E 6BTUK Department of Earth Sciences University College LondonLondonWC1E 6BTUK Centre for Planetary Science University College London and Birkbeck CollegeLondonWC1E 7HXUK Innovation Center of Ore Resources Exploration Technology in the Region of Bedrock Ministry of Natural Resources of People’s Republic of China’Guiyang550000China Guizhou Bureau of Geology and Mineral Exploration and Development Guiyang550000China

The Ediacaran–Cambrian Phosphogenic Episode is the Earth’s first true phosphogenic event and resulted in worldwide phosphate deposits,which occurred during the processes of the Neoproterozoic Oxygenation Event.The Ediacaran Doushantuo Formation(ca.635–551 Ma)of Weng’an area in central Guizhou,South China,contains two economic phosphorite beds(the Lower and Upper Phosphorite Beds).This paper presents a detailed stratigraphic,sedimentological and mineralogical study of multiple outcrop and drill core sections of the Doushantuo Formation across the Weng’an area,and identified 11 lithofacies and 4 types of phosphatic grains.Significant differences in lithofacies and grain types between the upper and lower phosphate deposits are observed,indicating that the two sets of phosphate deposits are the products of two distinct phosphogenic processes.The Lower Phosphorite Bed mainly consists of banded and laminated phosphorites,contains micro-oncoids formed by microbially-mediated precipitation and peloids formed by in-situ chemically oscillating reactions,indicating a biochemical and chemical enrichment of phosphorus to sediments during the Early Ediacaran Period.The Upper Phosphorite Bed is mainly composed of carbonaceous,massive,and stromatolitic phosphorites,contains bioclasts(phosphatized spheroidal fossils),and intraclasts formed by hydrodynamic agitation,suggesting that the major accesses of phosphorus to sediments were the remineralization of organic P.Deposition of the two economic phosphorite beds was controlled by two sea-level cycles.Such differences have also been documented in contemporaneous phosphate-bearing successions in Brazil and Mangolia,indicating a significant shift in global phosphogenic mechanism during the early and middle Ediacaran,which may be due to the changes in redox conditions in seawater,associated with the Neoproterozoic Oxygenation Event.These regional active P-cycle processes could produce more free oxygen,which may have contributed to the upcoming Phanerozoic global oxidation.

关键词： phosphorite lithofacies phosphatic grains phosphogenic paragenesis phosphorus cycle mineralogy

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Multi-scale analysis of carbon mineralization in lime-treated soils considering soil mineralogy

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2296-2309页

作者： Dhanalakshmi Padmaraj Chinchu Cherian Dali Naidu Arnepalli Department of Civil Engineering Indian Institute of Technology MadrasChennai600036India University of Northern British Columbia Prince GeorgeBCV2N4Z9Canada

Mineral carbonation is emerging as a reliable CO_(2) capture technology that can mitigate climate change.In lime-treated clayey soils,mineral carbonation occurs through the carbonation of free lime and cementitious products derived from pozzolanic reactions.The kinetics of the reactions in lime-treated clayey soils are variable and depend primarily on soil mineralogy.The present study demonstrates the role of soil mineralogy in CO_(2) capture and the subsequent changes caused by carbon mineralization in terms of the unconfined compressive strength(UCS)of lime-treated soils during their service life.Three clayey soils(kaolin,bentonite,and silty clay)with different mineralogical characteristics were treated with 4%lime content,and the samples were cured in a controlled environment for 7 d,90 d,180 d,and 365 d.After the specified curing periods,the samples were exposed to CO_(2) in a carbonation cell for 7 d.The non-carbonated samples purged with N2 gas were used as a benchmark to compare the mechanical,chemical-mineralogical,and microstructure changes caused by carbonation reactions.Experimental investigations indicated that exposure to CO_(2) resulted in an average increase of 10%in the UCS of limetreated bentonite,whereas the strength of lime-treated kaolin and silty clay was reduced by an average of 35%.The chemical and microstructural analyses revealed that the precipitated carbonates effectively filled the macropores of the treated bentonite,compared to the inadequate cementation caused by pozzolanic reactions,resulting in strength enhancement.In contrast,strength loss in lime-treated kaolin and silty clay was attributed to the carbonation of cementitious phases and partly to the tensile stress induced by carbonate precipitation.In terms of carbon mineralization prospects,lime-treated kaolin exhibited maximum carbonation due to the higher availability of unreacted lime.The results suggest that,in addition to the increase in compressive strength,adequate calcium-bearing phases and macropores determine the effic

关键词： Clays mineralogy Carbon capture Lime Strength Pore structure

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Determination of uncertainties of geomechanical parameters of metamorphic rocks using petrographic analyses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 345-364页

作者： Behzad Dastjerdy Ali Saeidi Shahriyar Heidarzadeh Department of Applied Sciences University of Quebec at ChicoutimiSaguenayQCCanada SNC-Lavalin MontrealCanada

Geomechanical parameters of intact metamorphic rocks determined from laboratory testing remain highly uncertain because of the great intrinsic variability associated with the degrees of metamorphism.The aim of this paper is to develop a proper methodology to analyze the uncertainties of geomechanical characteristics by focusing on three domains,i.***.data treatment process,schistosity angle,and mineralogy.First,the variabilities of the geomechanical laboratory data of Westwood Mine(Quebec,Canada)were examined statistically by applying different data treatment techniques,through which the most suitable outlier methods were selected for each parameter using multiple decision-making criteria and engineering judgment.Results indicated that some methods exhibited better performance in identifying the possible outliers,although several others were unsuccessful because of their limitation in large sample size.The well-known boxplot method might not be the best outlier method for most geomechanical parameters because its calculated confidence range was not acceptable according to engineering judgment.However,several approaches,including adjusted boxplot,2MADe,and 2SD,worked very well in the detection of true outliers.Also,the statistical tests indicate that the best-fitting probability distribution function for geomechanical intact parameters might not be the normal distribution,unlike what is assumed in most geomechanical studies.Moreover,the negative effects of schistosity angle on the uniaxial compressive strength(UCS)variabilities were reduced by excluding the samples within a specific angle range where the UCS data present the highest variation.Finally,a petrographic analysis was conducted to assess the associated uncertainties such that a logical link was found between the dispersion and the variabilities of hard and soft minerals.

关键词： Intact rock parameters Natural variabilities Outlier detection methods Uncertainties Westwood mine mineralogy

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In-situ analysis and genetic investigation of Li-bearing minerals in McDermitt clay-type lithium deposit,Nevada,USA

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Acta Geochimica 2024年第3期43卷 478-488页

作者： Yi Cui Hanjie Wen Zhengbing Zhou Kunyue Ling Lin Xu Shirong Liu Fei Xu School of Earth Sciences East China University of TechnologyNanchang 330013China State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang 330013China School of Earth Sciences and Resources Chang’an UniversityXi’an 710054China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

Clay-type Li deposits are poised to play a pivotal role in addressing the surging global demand for Li.The McDermitt clay-type Li deposit,located in Nevada,is the largest Li deposit in the United States,with Li hosted by a clay-rich sequence of smectite-dominated intervals and illite-dominated intervals,respectively.However,the occurrence of Li and the genesis of Li-bearing minerals within smectite-dominated intervals have not been thoroughly investigated in previous research.Here,we studied the mineralogy,the in-situ Li distribution,and the bonding environments of Li within the smectite intervals using a combination of instru-mental techniques including scanning electron microscope,transmission electron microscope,time-of-flight secondary ion mass spectrometry,and nuclear magnetic resonance.Our results indicate that the smectite exhibits low crystallinity characteristics of lacustrine clay authigenesis and is com-monly found tofill the interstices among volcanic minerals or envelop them;Li is mainly hosted by Mg-smectite rather than the volcanic minerals.Within the tuffaceous sediment samples,the volcanic glass has undergone a transformation,resulting in its complete disappearance and alteration into clay minerals.Owing to the octahedral sites of Mg-smectite bounded in Li,it is referred to be hectorite.We interpret that the hectorite’s precipitation occurs in a high saline-alkaline water environment,a result of McDermitt tuffdissolution.This conclusion can be supported by the coexistence of spherulitic calcite and hectorite.Overall,this study confirms hectorite as the main Li-bearing mineral and increases the understanding of the genetic model of hectorite formation in intracontinental caldera basins.

关键词： McDermitt caldera Lithium occurrence Tuffaceous sediments mineralogy Hectorite neoformation

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有色金属：选矿部分

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有色金属：选矿部分

作者：朱穗玲

出版周期：双月刊

出版社：矿冶科技集团有限公司

本刊为专业科技期刊。主要反映有色金属选矿专业的最新科研成果和前沿动态，发表高水平的学术论文。主要栏目有：选矿工艺、选矿设备、选矿药剂、选矿自动化等。读者对象为有色金属行业科研与设计人员、厂矿企业工程技术人员及大专院师生。

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Clay Materials for Ceramics Application from N’Djamena in the Chad Republic: Mineralogical, Physicochemical and Microstructural Characterization

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Journal of Materials Science and Chemical Engineering 2024年第2期12卷 31-48页

作者： Ndjolba Madjihingam Djoda Pagore Jacques Richard Mache Bebbata Warabi Bertin Pagna Kagonbe Patrick Mountapmbeme Kouotou Department of Civil Engineering National Advanced School of Engineering University of Maroua Maroua Cameroon Department of Mining Engineering School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Local Materials Authority Promotion (MIPROMALO) Yaoundé Cameroon Department of Environmental Sciences Advanced School of Agriculture Forestry Water and Environment University of Ebolowa Ebolowa Cameroon

Herein, we report some characteristics of the clayey materials (CMs) collected from Kaliwa (C1), Kabé (C2) and Malo (C3) district in N’Djamena (Chad). Three samples were characterized applying XRF, XRD, FTIR, SEM. In addition, TGA/DSC were performed to control decomposition/mass loss and show phase transitions respectively of CMs. Geochemical analysis by XRF reveals the following minerals composition: SiO2 (~57% - 66%), Al2O3 (~13% - 15%), Fe2O3 (~6% - 10%), TiO2 (~1% - 2%) were the predominant oxides with a reduced proportion in C1, and (~7%) of fluxing agents (K2O, CaO, Na2O). Negligible and trace of MgO (~1%) and P2O5 was noted. The mineralogical composition by XRD shows that, C1, C2 and C3 display close mineralogy with: Quartz (~50%), feldspar (~20%) as non-clay minerals, whereas clays minerals were mostly kaolinite (~15%), illite (~5%) and smectite (~10%). FTIR analysis exhibits almost seemingly similar absorption bands characteristic of hydroxyls elongation, OH valence vibration of Kaolinite and stretching vibration of some Metal-Oxygen bond. SEM micrographs of the samples exhibit microstructureformed by inter-aggregates particles with porous cavities. TGA/DSCconfirm the existence of quartz (570˚C to 870˚C), carbonates (600˚C - 760˚C), kaolinite (569˚C - 988˚C), illite (566˚C - 966˚C), MgO (410˚C - 720˚C) and smectite (650˚C - 900˚C). The overall characterization indicates that, these clayey soils exhibit good properties for ceramic application.

关键词： Clay Soils Characterization mineralogy Physicochemical Properties Ceramic Application

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mineralogy and element geochemistry of the Sohnari rocks of Early Eocene Laki Formation in the Southern Indus Basin,Pakistan:Implications for paleoclimate,paleoweathering and paleoredox conditions

能源地球科学(英文)

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能源地球科学(英文) 2023年第1期4卷 143-157页

作者： Asghar A.A.D.Hakro Sajjad Ali Abdul Shakoor Mastoi Riaz Hussain Rajper Rizwan Sarwar Awan Muhammad Soomar Samtio Hong Xiao Xiaolin Lu Centre for Pure&Applied Geology University of SindhJamshoro76080Pakistan Xinjiang Centre for Mineral Resources Xinjiang Institute of Ecology and GeographyUrumqiXinjiang830011China College of Geosciences China University of PetroleumBeijing102249China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China School of Resources and Environmental Engineering Hefei University of TechnologyHefei Anhui230009China

The Sohnari Member of the Early Eocene Laki Formation is massively deposited in the Southern Indus Basin of Pakistan and is considered a potential source rock to generate hydrocarbons.However,the detailed paleoclimatic,paleoweathering,and depositional conditions of the Sohnari Member have not been studied earlier.This research mainly discusses the detailed mineralogical(bulk and clay)and elemental geochemistry of the Laki Formation from two outcrop sections(Jhimpir and Lakhra)in the Southern Indus Basin,Pakistan.The bulk minerals,including quartz(low),hematite,calcite,halite,gypsum,and clay minerals such as kaolinite,chlorite,smectite and illite have been discussed here.These results demonstrate the paleo-environment of studied area was arid with enhanced saline and weak to strong oxidizing depositional conditions.The chemical index of alteration(CIA)values in Jhimpir and Lakhra sections are in the ranges of 41.30-97.93 and 22.30-96.19,respectively,indicating that the Sohnari sediments experienced weak to intense chemical weathering in the source area.The interpretation of the A-CN-K ternary diagram is consistent with the clay mineral contents in the studied sediments,which is characterized by the predominance of kaolinite,gibbsite and chlorite,demonstrating the weak to strong weathering state under warm and humid climatic conditions.The chemical indices such as Sr/Ba,δU,V/Cr,Ni/Co,and Cu/Zn,U/Th and Ba/Ga show that Sohnari rocks of Early Eocene Laki Formation underwent strong evaporation,oxic water column with warm to humid and minor contact of cold climatic conditions.Based on our present data,it can be concluded that the sediments of Sohnari Member of Laki Formation from Jhimpir and Lakhra areas of Southern Indus Basin in Pakistan are related to Indio-Eurasian collision and came from the Indian shield rocks that were deposited in a brackish water body with a minor contact of the freshwater oxidizing paleo-environment depositional conditions.

关键词： mineralogy Geochemistry Paleoclimate Sohnari Southern indus basin Lakhra

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mineralogy and geochemistry of hydrothermal sulphide from a submarine volcanic high at 18°36.4'S Central Lau Spreading Center, Southwest Pacific

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Acta Oceanologica Sinica 2023年第5期42卷 93-101页

作者： Durbar Ray Anil L.Paropkari CSIR-National Institute of Oceanography Dona PaulaGoa 403004India Retired Chief Scientist CSIR-National Institute of OceanographyGoa 403004India

We report the mineralogy and geochemistry of hydrothermal sulphide from the crater of a volcanic high near 18°36.4′S of the Central Lau Spreading Center.During 1990s,that volcanic structure was reported active and sulphide samples were collected by MIR submersible.A section of a chimney-like structure from the crater-floor was studied here.The Fe-depleted sphalerites,and Co-depleted pyrites in that chimney were similar to those commonly found in low to moderate temperature(mineralogy and bulk composition of subsamples across the chimney section suggests barely any alteration of fluid composition and/or mode of mineralisation occurred during its growth.

关键词： Central Lau Spreading Center hydrothermal sulphide mineralogy geochemistry

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Characteristics of the lunar samples returned by the Chang'E-5 mission

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National Science Review 2022年第2期9卷 21-33页

作者： Chunlai Li Hao Hu Meng-Fei Yang Zhao-Yu Pei Qin Zhou Xin Ren Bin Liu Dawei Liu Xingguo Zeng Guangliang Zhang Hongbo Zhang Jianjun Liu Qiong Wang Xiangjin Deng Caijin Xiao Yonggang Yao Dingshuai Xue Wei Zuo Yan Su Weibin Wen Ziyuan Ouyang Key Laboratory of Lunar and Deep Space Exploration National Astronomical Observatories Chinese Academy of Sciences Lunar Exploration and Space Engineering Center Beijing Institute of Spacecraft System Engineering Department of Nuclear Physics China Institute of Atomic Energy State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Institute of Geochemistry Chinese Academy of Sciences

Forty-five years after the Apollo and Luna missions returned lunar samples,China’s Chang’E-5(CE-5)mission collected new samples from the mid-latitude region in the northeastern Oceanus Procellarum of the Moon.Our study shows that 95% of CE-5 lunar soil sizes are found to be within the range of 1.40-9.35 μm,while 95% of the soils by mass are within the size range of 4.84-432.27 μm.The bulk density,true density and specific surface area of CE-5 soils are 1.2387 g/cm~3,3.1952 g/cm~3 and 0.56 m~2/g,respectively.Fragments from the CE-5 regolith are classified into igneous clasts(mostly basalt),agglutinate and glass.A few breccias were also found.The minerals and compositions of CE-5 soils are consistent with mare basalts and can be classified as low-Ti/low-Al/low-K type with lower rare-earth-element contents than materials rich in potassium,rare earth element and phosphorus.CE-5 soils have high FeO and low Mg index,which could represent a new class of basalt.

关键词： Chang’E-5 lunar soils physical properties petrography mineralogy chemistry

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mineralogy and geochemistry of the Ngaoundaba Crater Lake sediments,northern Cameroon:implications for provenance and trace metals status

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Acta Geochimica 2021年第5期40卷 718-738页

作者： Armel Zacharie Ekoa Bessa John SArmstrong-Altrin Gentry Calistus Fuh Thierry Bineli Betsi Tebogo Kelepile Paul-DesireNdjigui Department of Earth Sciences University of Yaounde IP.O.Box 812YaoundeCameroon Universidad Nacional Autonoma de Mexico Instituto de Ciencias del Mar Y LimnologıaUnidad de Procesos Oceanicos y CosterosCircuito exterior s/n04510 MexicoD.F.Mexico Department of Mining and Geological Engineering Botswana International University of Sciences and TechnologyPrivate Bag 16PalapyeBotswana

This study was conducted on the Ngaoundaba Crater Lake sediments to infer provenance,weathering conditions,organic matter accumulation,and trace metal concentrations.Ngaoundaba Lake sediments were collected using a manual core sampler at 5 to 8 m water depth.Two sediment cores from the littoral and center of the lake were analyzed for grain size distribution,water content(WC),organic matter content,mineralogy,and major and trace element concentrations.The Ngaoundaba sediments were classified as silt and sandy silt.Sediments show high content in organic matter,which is more to the littoral than to the center of the lake,varying from 14.6%to 24%and21.2%to 40.8%,respectively.The grain surface features identified by Scanning Electron Microscopy(SEM)show both chemical and mechanical microtextures with subrounded to angular shape suggesting both proximal and distal sources.The lake sediments are composed of quartz,kaolinite,and hematite,with low amounts of feldspars,rutile,calcite,illite,and ilmenite.Weathering indices such as the chemical index of alteration(CIA),chemical index of weathering(CIW),and index of compositional variability(ICV)indicate moderate to intense chemical weathering in the source area and immature to mature sediments.The geochemical composition indicates that the sediments were derived from felsic to intermediate igneous rocks,such as granitoids,and mafic alkali lavas like basanites.The environmental risk assessment of trace metals obtained by enrichment factor(EF)and geo-accumulation index(I-geo)shows low contamination of the lake sediments.

关键词： Ngaoundaba Crater Lake mineralogy Geochemistry Provenance Metal traces status

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