Origin and Role of Kaolinization in Roll-Front Uranium Deposits and Its Response to Ore-Forming Fluids in the Yili Basin, China

Figure 3

(a) Red sandstone with oxidized organic moulages in strong oxidation zone. (b) Yellowish-white sandy conglomerate dotted with red limonite in weak oxidation zone. (c) Gray mineralized sandy conglomerate. (d) Grayish-white sandstone containing carbon debris in primary zone. (e) Leached feldspar grain and pores filled with micritic kaolinite. (f) Micritic kaolinite covering quartz grains. (g) Vermicular kaolinite coexisting with micritic kaolinite. (h) Vermicular kaolinite superposed by micritic kaolinite. (i) Micritic kaolinite coexisting with gypsum and superposed upon vermicular kaolinite. (j) Authigenic quartz grains in intergranular pore covered by micritic kaolinite. (k) Strong quartz overgrowth covered by micritic kaolinite. (l) Quartz overgrowth replaced with micritic kaolinite.

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