Earth Science Frontiers ›› 2024, Vol. 31 ›› Issue (4): 258-280.DOI: 10.13745/j.esf.sf.2023.11.20

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Geochemical characteristics and genesis of lithium rich clay rocks in the Pudi area of northwestern Guizhou

ZHANG Qidao1,2(), LI Dezong1,2,*(), LI Zhiwei1,2, WANG Donghui1,2, YU Yifan1,2, ZHU Xingqiang1,2, CAI Quanyu1,2, LI Ming1,2   

  1. 1. Kunming General Survey of Natural Resources Center, China Geological Survey, Kunming 650100, China
    2. Technology Innovation Center for Natural Ecosystem Carbon Sink, Ministry of Natural Resources, Kunming 650100, China
  • Received:2023-09-04 Revised:2023-10-26 Online:2024-07-25 Published:2024-07-10

Abstract:

The Permian Liangshan Formation in the Pudi area of northwest Guizhou Province directly overlays the Cambrian Loushanguan Formation, exhibiting abnormal lithium enrichment in its clay rocks. Studying the enrichment mechanism provides valuable insights for lithium resource development and evaluation in clay rocks, as well as understanding lithium accumulation mechanisms. Various analytical methods including LA-ICP-MS, mapping, AMICS, XRD, SEM, along with U-Pb chronology, are employed to elucidate the elemental geochemistry, provenances, and occurrence states of lithium enrichment in clay rocks. Results reveal lithium-rich clay rocks primarily in the middle and lower sections of the Permian Liangshan Formation, with their occurrence controlled by the karst unconformity surface of the underlying Loushanguan Formation dolomite. Enriched elements such as Li, Ga, V, Nb, Zr, and F are identified, while Ba and Sr are relatively depleted. Light rare earth elements (La, Ce, Nd) predominate, with Y as the main heavy rare earth element. Lithium-rich clay rocks comprise terrestrial deposits with characteristics of terrestrial, transitional, and marine phases, formed in an oxidized environment under a tropical-subtropical warm and humid climate. The zircon age spectrum exhibits five peaks at 2.5 Ga, 1.4 Ga, 980 Ma, 780 Ma, and 530 Ma, with the main peaks at 980 Ma, 780 Ma, and 530 Ma. Lithium in the clay rocks mainly occurs within kaolinite, indicating multiple sources, with impure dolomite of the Cambrian Loushanguan Formation likely being the primary source.

Key words: enrichment mechanism, provenances, existence state, sedimentary lithium deposit, Pudi area, northwest Guizhou

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