克鲁伦凹陷大磨拐河组沉积体系演化与赋铀性

克鲁伦凹陷下白垩统大磨拐河组是海拉尔盆地寻找可地浸砂岩型铀矿的目的层。大磨拐河组主要发育冲积扇、扇三角洲和湖相 3种沉积体系。根据沉积环境和沉积物特征 ,可将冲积扇划分为扇根、扇中和扇端 3种亚相 ;扇三角洲划分为上扇三角洲平原、下扇三角洲平原、扇三角洲前缘和前扇三角洲亚相。凹陷北缘发育两个扇体 ,扇三角洲体系和冲积扇体系之间在不同时期可相互转化。区内的陆源粗碎屑沉积岩为铀的富集创造了有利条件 ,扇三角洲和冲积扇的主河道和分流河道是最有利于铀聚集的部位。

Evolution of depositional system and uraniferous characteristics of Damoguaihe Formation in Kelulun Sag

Damoguaihe Formation,which is mainly of alluvial fan,fan delta and lacustrine depositional systems,is the target horizon for the prospecting of sandstone-type uranium deposit in Kelulun sag,Hailaer basin.According to the depositional environment and sediment characteristics,alluvial fan facies is subdivided into upper fan,middle fan and lower fan subfacies;the fan delta facies is subadivided into upper fan delta plain,lower fan delta plain,fan delta front and fan prodelta subfacies.At the northern edge of the sag occurred one fan delta and one alluvial fan,which can mutually transform one into another.The terrigenous coarse-grained clastic deposits in the study area provide favorable condition for the concentration of uranium and especially the main channels and distributary channels on the fan delta and alluvial fan are the most favorable sites for uranium concentration.