舍伯吐地区第三系沉积体系及对可地浸砂岩型铀成矿的作用

Analysisi on depositional systems of Tertiary with respect to uranium ore-formation of in-situ leachable sandstone-type uranium deposits in Shebotu area

舍伯吐地区位于松辽盆地西南部,笔者通过沉积体系分析认为,该区第三系中新统大安组以低水位体系域的辫状河相沉积为主,上新统泰康组以水进和高水位体系域的曲流河相沉积为主,目前已发现的铀矿化主要产于泰康组水进体系域的曲流河边滩亚相中。综合分析认为,有利的成矿部位应为低水位体系域的大安组辫状河河道心滩亚相。

The Shebotu area is located in the southwest of Songliao basin.Based on the analysis of depositional systems this paper suggests that sediments of the Da'an Formation,Miocene are mainly attributed to braided stream facies of low stand tracts,and the Taikang Formation,Pliocene is mainly of meandering stream facies of transgressive and high stand tracts.Uranium mineralization basically occurs in point bar subfacies of meandering stream in transgressive system tracts of Taikang Formation.On the basis of comprehensive analysis it is suggested that the most favourable sites for uranium ore-formation are sediments of braided stream channel-point bar subfacies of Da'an Formation of low stand system tracts.