二连盆地川井坳陷构造演化对砂岩型铀矿成矿作用的约束

Constraints of Tectonic Evolution on Sandstone-Type Uranium Metallogenesis in the Chuanjing Depression,Erlian Basin

川井坳陷位于二连盆地西部,坳陷内目的层赛汉组上段发育辫状河、辫状河三角洲-湖沼沉积,砂体发育。受构造、构造演化影响,在坳陷东部发育晚白垩世苏海布龙剥蚀窗口,在坳陷西部白音查干地区发育古近纪剥蚀窗口,剥蚀窗口控制了后生含铀含氧流体向盆地内入渗参与成矿,找矿类型为赛汉期斜坡带型及古河谷型。东西二个剥蚀窗口的发现,为合理解释已发现的矿化异常、找矿预测模型的构建提供了基础。通过构建坳陷三位一体找矿预测模型,本文预测了苏海布龙、白音查干西及包龙凹陷东三个铀成矿远景区。

The Chuanjin depression is located in the west of the Erlian basin,where the upper member of the Saihan Formation with in braided rivers and braided river delta-lacustrine sediments were developed.Influenced by tectonic evolution,the Late Cretaceous Suhaibulong and Paleogene Baiyinchagan erosion windows formed in the east and west parts of the depression,respectively.These erosion windows controlled the uranium-bearing and oxygen-bearing fluid into the basin,which participated in the mineralization.The ore prospecting is of Saihan period slope type and paleovalley type.The discovery of the two erosion windows provides basis for reasonable interpretation of the previously discovered mineralization anomalies and construction of the prediction model.By constructing a trinity ore prediction model,this work forecasted three uranium mineralization areas,i.e.,Suhaibulong,Baiyinchagan and Baolong.