二连盆地川井坳陷铀成矿环境及成矿有利地段研究

Study of uranium metallogenetic circumstance and metallogenetic prospective area selection in Chuanjin depression,Erlian basin

本文在简述二连盆地川井坳陷区域地质、区域水文地质特征的基础上 ,重点阐述了白垩系岩性岩相特点、岩石后生蚀变和铀矿化特征 ,并得出坳陷在纵横两方向上存在着较大的分割性和不均匀性 ,白音查干凹陷砂体属三角洲相叠加了河流相的新认识 ,进而提出了下白垩统为湖相→三角洲相→河流相的连续演化系列。从宏观、微观两方面论述了白音查干凹陷潜水和层间氧化带砂岩型铀矿成矿前景 ,同时 ,分片对整个川井坳陷成矿有利及不利因素作了评价。在对古河道发育情况、基底、构造、水文地质和后生蚀变、有机质等成矿条件分析的基础上 。

On the basis of a brief introduction of regional geology and regional hydrogeology of Chuanjin depression,this article mainly expounds lithology-lithofacies features of Cretaceous and the epigenetic alteration of rocks, and uranium mineralization characteristics in Chuanjin depression.Authors conclude that the depression is quite separated and heterogeneous;sand bodies in Baiyinchagan sag belong to the delta facies superimposed by fluvial facies. Authors therefore propose a lacustrine-delta-fluvial facies successive evolutionary depositional model of Lower Cretaceous,and discuss from both microscopic and macroscopic aspects the prospect of phreatic and interlayer oxidation zone sandstone uranium ore-formation in Baiyinchagan sag,and make an analysis of both favorable and unfavorable metallogenic conditions for the sag in whole,and for different parts of the sag in particular. According to the analysis of metallogenic conditions such as the development of paleochannel,basement,structure,hydrogeology,epigenetic alteration,organic material etc.,a prospective metallogenic area for paleochannel sandstone-type uranium deposit--the southwestern edge of Sanggendalai sag,in the eastern part of Chuanjin depression is selected.