ZHANG Cheng-yong1, NIE Feng-jun1, HOU Shu-ren2, DENG Wei1, WANG Jun-lin2, ZHANG Liang2
(1. East China Institute of Technology, Nanchang 330013, China;
2. China University of Geosciences, Wuhan 430074, China;
3. Geologic Party No.208, CNNC, Baotou 014010, China)
Anstract: Tamusu sandstone type uranium deposits in Bayingobi basin, Inner Mongolia, China have obvious characteristics of epigenetic alteration, such as universal consolidation of the target layer, a multilayer with poor continuity of ore body, and irregular distribution. Through a survey of outcrops, core observation and microscopic analysis, this study found that interlayering of gypsum or calcite veins, hydrothermal sulphide minerals, recrystallization and new cements are common in this area, with sulphate-metal sulphide minerals coexisting and fractionation in their S isotope. All of above indicate epigenetic hydrothermal fluid activities. Analysis of the orebody shape, ore characteristics and the formation of uranium minerals indicate the thermal activities occurred during the late period of the interlayer oxidation. As temperature rose, CaSO4 and CaCO3 began to precipitate and destroyed the balance of uranium complexes, causing a precipitation of uranium and prompting the enrichment of uranium mineralization.
Keywords: sandstone type uranium deposit; uranium mineralization; metal sulfide; thermal fluid overlay; Tamusu, Inner Mongolia
E-mail: cyzh@ecit.cn
ACTA MINERALOGICA SINICA Vol. 35, No. 1, 2015, Page 79-86
