{"title":"印度磷矿的临界矿物潜力:库达帕盆地埃迪卡拉系沉积物中稀土元素富集的证据","authors":"Gangula Harshitha , Ignacio González-Álvarez , Chakravadhanula Manikyamba , Joëlle D'Andres , Jayant Kumar Yadav , Mrinal Kanti Mukherjee","doi":"10.1016/j.gexplo.2025.107918","DOIUrl":null,"url":null,"abstract":"<div><div>Phosphorites constitute a potential non-traditional source of rare earth elements (REE), although their resource viability is still being evaluated globally. This study presents the first documentation of REE-enriched sediment-hosted phosphorites from India, and evaluates the processes driving REE mobilization, enrichment and accumulation. The Ediacaran phosphatic beds from the Owk Shale Formation, Kurnool Group of the Cuddapah basin, interbedded with shales and tuffs, were analysed using optical and SEM imaging, whole rock geochemical, in-situ fluorapatite (EPMA, LA-ICP-MS) and Raman spectroscopic analyses. Two apatite phases were identified: primary authigenic (Ap-1), fluorine-poor variety and secondary/reprecipitated REE-enriched fluorapatite (Ap-2). Whole-rock REE + Y concentrations reach up to 1075 ppm, with characteristic middle REE (MREE) enriched patterns, also recorded in fluorapatite, interpreted as a result of diagenetic uptake from sediment porewaters. A strong correlation between REE + Y and redox tracer, Mn indicates initial MREE scavenging by Mn-(oxy)hydroxides and organic matter, followed by MREE release during Mn-reductive dissolution. While diagenesis enhanced REE enrichment, post-diagenetic hydrothermal reworking associated with igneous intrusions diluted REE concentrations through the formation of abundant Fe<img>Mg chlorite (chamosite) and REE and P redistribution within the interbedded shales. Sequence stratigraphic analysis suggests that these pristine phosphorites were deposited during marine regression, without subsequent reworking, preventing the formation of high grade phosphorite deposit, emphasizing the role of sea-level changes in controlling phosphogenesis, formation of a phosphorite giant and thus, REE enrichment. A temporal analysis of global phosphorites further reveals that progressive seawater influence, modulated by biogeochemical recycling and episodic weathering, together controlled the REE enrichment patterns in phosphorites through Earth's history.</div></div>","PeriodicalId":16336,"journal":{"name":"Journal of Geochemical Exploration","volume":"280 ","pages":"Article 107918"},"PeriodicalIF":3.3000,"publicationDate":"2025-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Critical mineral potential of Indian phosphorites: Evidence of REE enrichment in Ediacaran sediments from the Cuddapah Basin\",\"authors\":\"Gangula Harshitha , Ignacio González-Álvarez , Chakravadhanula Manikyamba , Joëlle D'Andres , Jayant Kumar Yadav , Mrinal Kanti Mukherjee\",\"doi\":\"10.1016/j.gexplo.2025.107918\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Phosphorites constitute a potential non-traditional source of rare earth elements (REE), although their resource viability is still being evaluated globally. This study presents the first documentation of REE-enriched sediment-hosted phosphorites from India, and evaluates the processes driving REE mobilization, enrichment and accumulation. The Ediacaran phosphatic beds from the Owk Shale Formation, Kurnool Group of the Cuddapah basin, interbedded with shales and tuffs, were analysed using optical and SEM imaging, whole rock geochemical, in-situ fluorapatite (EPMA, LA-ICP-MS) and Raman spectroscopic analyses. Two apatite phases were identified: primary authigenic (Ap-1), fluorine-poor variety and secondary/reprecipitated REE-enriched fluorapatite (Ap-2). Whole-rock REE + Y concentrations reach up to 1075 ppm, with characteristic middle REE (MREE) enriched patterns, also recorded in fluorapatite, interpreted as a result of diagenetic uptake from sediment porewaters. A strong correlation between REE + Y and redox tracer, Mn indicates initial MREE scavenging by Mn-(oxy)hydroxides and organic matter, followed by MREE release during Mn-reductive dissolution. While diagenesis enhanced REE enrichment, post-diagenetic hydrothermal reworking associated with igneous intrusions diluted REE concentrations through the formation of abundant Fe<img>Mg chlorite (chamosite) and REE and P redistribution within the interbedded shales. Sequence stratigraphic analysis suggests that these pristine phosphorites were deposited during marine regression, without subsequent reworking, preventing the formation of high grade phosphorite deposit, emphasizing the role of sea-level changes in controlling phosphogenesis, formation of a phosphorite giant and thus, REE enrichment. A temporal analysis of global phosphorites further reveals that progressive seawater influence, modulated by biogeochemical recycling and episodic weathering, together controlled the REE enrichment patterns in phosphorites through Earth's history.</div></div>\",\"PeriodicalId\":16336,\"journal\":{\"name\":\"Journal of Geochemical Exploration\",\"volume\":\"280 \",\"pages\":\"Article 107918\"},\"PeriodicalIF\":3.3000,\"publicationDate\":\"2025-10-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Geochemical Exploration\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S037567422500250X\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geochemical Exploration","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S037567422500250X","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Critical mineral potential of Indian phosphorites: Evidence of REE enrichment in Ediacaran sediments from the Cuddapah Basin
Phosphorites constitute a potential non-traditional source of rare earth elements (REE), although their resource viability is still being evaluated globally. This study presents the first documentation of REE-enriched sediment-hosted phosphorites from India, and evaluates the processes driving REE mobilization, enrichment and accumulation. The Ediacaran phosphatic beds from the Owk Shale Formation, Kurnool Group of the Cuddapah basin, interbedded with shales and tuffs, were analysed using optical and SEM imaging, whole rock geochemical, in-situ fluorapatite (EPMA, LA-ICP-MS) and Raman spectroscopic analyses. Two apatite phases were identified: primary authigenic (Ap-1), fluorine-poor variety and secondary/reprecipitated REE-enriched fluorapatite (Ap-2). Whole-rock REE + Y concentrations reach up to 1075 ppm, with characteristic middle REE (MREE) enriched patterns, also recorded in fluorapatite, interpreted as a result of diagenetic uptake from sediment porewaters. A strong correlation between REE + Y and redox tracer, Mn indicates initial MREE scavenging by Mn-(oxy)hydroxides and organic matter, followed by MREE release during Mn-reductive dissolution. While diagenesis enhanced REE enrichment, post-diagenetic hydrothermal reworking associated with igneous intrusions diluted REE concentrations through the formation of abundant FeMg chlorite (chamosite) and REE and P redistribution within the interbedded shales. Sequence stratigraphic analysis suggests that these pristine phosphorites were deposited during marine regression, without subsequent reworking, preventing the formation of high grade phosphorite deposit, emphasizing the role of sea-level changes in controlling phosphogenesis, formation of a phosphorite giant and thus, REE enrichment. A temporal analysis of global phosphorites further reveals that progressive seawater influence, modulated by biogeochemical recycling and episodic weathering, together controlled the REE enrichment patterns in phosphorites through Earth's history.
期刊介绍:
Journal of Geochemical Exploration is mostly dedicated to publication of original studies in exploration and environmental geochemistry and related topics.
Contributions considered of prevalent interest for the journal include researches based on the application of innovative methods to:
define the genesis and the evolution of mineral deposits including transfer of elements in large-scale mineralized areas.
analyze complex systems at the boundaries between bio-geochemistry, metal transport and mineral accumulation.
evaluate effects of historical mining activities on the surface environment.
trace pollutant sources and define their fate and transport models in the near-surface and surface environments involving solid, fluid and aerial matrices.
assess and quantify natural and technogenic radioactivity in the environment.
determine geochemical anomalies and set baseline reference values using compositional data analysis, multivariate statistics and geo-spatial analysis.
assess the impacts of anthropogenic contamination on ecosystems and human health at local and regional scale to prioritize and classify risks through deterministic and stochastic approaches.
Papers dedicated to the presentation of newly developed methods in analytical geochemistry to be applied in the field or in laboratory are also within the topics of interest for the journal.