松辽盆地东北缘庆安地区泉头组沉积相与铀矿找矿潜力

Sedimentary Facies and Uranium Prospecting Potential of Quantou Formation in the Qing'an Area,Northeastern Margin of Songliao Basin

松辽盆地东北缘泉头组的沉积相与铀成矿条件研究相对薄弱。在岩心、测井资料综合分析的基础上,对庆安地区泉头组的沉积相特征进行了系统总结,并对区内砂岩型铀成矿地质条件进行了综合评价。认为:①泉头组可识别出冲积扇、扇三角洲、滨浅湖三种沉积相,可划分出泥石流、辫状河道、洪泛平原、水下分流河道、河口坝、水下分流间湾、前三角洲泥、滨浅湖泥、滩坝等九种微相;②泉头组为一个以湖侵序列占优、大的水进-水退沉积旋回,沉积充填以大规模的冲积扇-扇三角洲体系为特色;③水下分流河道砂体、河口坝砂体等有利砂体的北东-南西向展布特征是制约研究区铀矿勘查的主要控制因素,建议天增镇附近、铁力市西南地区可作为下一步工作的重点区加强探索。

Few rea searches have been done on the sedimentary facies and uranium metallogenic conditions of Quantou Formation in the Qing'an area,northeastern margin of Songliao Basin.This work,building on an analysis of core and logging data,attempts to undertake systematic research of this issue.Results show that the sedimentary facies in this area includes alluvial fan,fan-delta and shore-shallow lake depositional system.They can be further subdivided into nine microfacies:debris flow,braided channels,flood plains,underwater distributary channel,underwater distributary bays,estuary dams,prodelta-mud,lake mud and beach are identified.The whole Quantou Formation,with a dominant lacustrine transgression sequence,is a large transgressive-regressive sedimentary cycle,and the sedimentary filling is characterized by a large-scale alluvial fan to fan delta depositional system.The NE-SW directed distribution of favorable sand bodies,such as underwater distributary channel sandbodies and mouth bar sandbodies,are the key geological factors restricting uranium exploration in the study area.It is suggested that Tianzeng Town and the southwestern Tieli City should be the key areas for further sandstone-type uranium exploration.