关键词: 流体包裹体, 烃类充注, 热事件, 铀矿成因, 东胜地区

Abstract: The measurement of homogeneous temperature and chemical component and the fluorescence analysis of fluid inclusion in the uranium-bearing sandstone and diagenetic sequence indicated that there were at least three phases of hydrocarbon-related fluid injection and migration in Zhiluo Formation of the Dongsheng area in Ordos Basin.The characteristics of the fluid demonstrated an evolution process of hydrocarbon from low maturity in the early phase to high maturity in the late phase.The fluid inclusions contained a large amount of CO₂,hydrocarbons(CH₄ and C₂⁺) and reduction gas(H₂S and H₂).The uranium-bearing sandstones contained rich carbonate cement.Reduction gases provided a favorable condition for uranium precipitation and accumulation.The depositions of CO₂ and carbonate cement in the formation had an important positive impact on uranium precipitation and accumulation.Hydrocarbon injection and emplacement had a close relationship with the origin of uranium mineralization.The homogeneous temperature of fluid inclusions and other related evidences showed that the tectonic thermal events once occurred in this area.The occurrence of the tectonic thermal events coincided with the uranium mineralization in the early stage,thus the thermal event had contribution to the uranium mineralization.

Key words: fluid inclusions, hydrocarbon injection episode, tectonic thermal event, uranium mineralization origin, Dongsheng area