Provenance and ore-forming process of Permian lithium-rich bauxite in central Yunnan, SW China

• DOI: 10.1016/j.oregeorev.2022.104862
• Publication Date: 2022-03-30T00:53:38Z
• Authors: Jing-Yuan Zhang; Qingfei Wang; Xue-Fei Liu; Guo-Fa Zhou; Hai-Peng Xu; Yi-Guang Zhu
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

Permian lithium-rich karstic bauxites are newly discovered in central Yunnan province, western margin of the South China Block, with a reserve 16 million tonnes, which has great potential for aluminum and lithium exploitation. Provenance ore-forming processes still debatable. Mineralogical, geochemical, geochronological analyses were conducted on two typical bauxite profiles to explore genetic process province. Profile A contains three layers from bottom top: clayey bauxite, claystone, pisolitic bauxite. B five mottled claystone. Pisolitic mainly consists diaspore chamosite, small amounts goethite, anatase, boehmite. Clayey dominantly boehmite kaolinite, anatase. Claystone predominantly kaolinite or illite. Three stages formation identified: (1) during weathering regional sedimentary strata, boehmite, illite formed; (2) deposition, diaspore, pyrite, illite, barite (3) second exposure caused by paleo-uplift, goethite was formed. Correlation demonstrate that is most likely host mineral Li studied leaching after deposition can significantly reduce contents. Two profiles' differences sequence be attributed their different locations paleokarst terrain. Topography karst terrain controls conditions, thus affecting mineralogy profiles. In our case, uplifted area not submerged at first, then as groundwater rose, immersed. Therefore, conditions areas changed oxidizing reducing became more alkaline. contrast, depression throughout deposition. All formed under alkaline conditions. Data U-Pb isotope measurements detrital zircons province provides 3 main ages, 500–650 Ma, 800 980 Ma. There several minor peak ages age spectrum, 288–310 1500 1800 2000 2500 Age distribution pattern similar Ordovician units than other rocks indicates major contribution eroded bauxites.