黑龙江北部孙吴——嘉荫盆地沉积相类型及其演化

通过对孙吴-嘉荫盆地淘淇河组、永安村组、太平林场组、鱼亮子组、乌云组和孙吴组露头剖面详细的沉积学研究,查明该盆地从淘淇河组到孙吴组发育的沉积相类型有冲积扇、辫状河、曲流河、扇三角洲、辫状河三角洲、曲流河三角洲、湖底扇和湖泊。冲积扇及扇三角洲主要发育于淘淇河组和孙吴组;辫状河及辫状河三角洲主要发育于鱼亮子组和乌云组;曲流河及曲流河三角洲主要发育于永安村组和太平林场组,各组均有湖泊相沉积发育。孙吴-嘉荫盆地从淘淇河组到乌云组,具有冲积扇-扇三角洲-湖泊→曲流河-曲流河三角洲-湖泊→辫状河-辫状河三角洲-湖泊→冲积扇-扇三角洲-湖泊的沉积演化规律,反映晚白垩-古新世构造活动性减弱,中-上新世孙吴组沉积时重又趋于活动。

Sedimentary facies types and evolution of the Sunwu-Jiayin Basin in northern Heilongjiang province

The Sunwu-Jiayin Basin in northern Heilongjiang province is a Meso-Cenozoic sedimentary basin,with the stratigraphic records being the Lower Cretaceous Taoqihe Formation,the Upper Cretaceous Yongancun,Taipinglinchang and Yuliangzi Formations,the Paleocene Wuyun Formation and the Miocene-Pliocene Sunwu Formation.The results of detailed sedimentary study on the main outcrop sections in the basin indicated that there developed the deposits with facies of alluvial fan,braided river,meandering river,fan-delta,braided river delta,meandering river delta,lake floor fan and lacustrine.The deposits with facies of alluvial fan and fan-delta mainly occurred in the Taoqihe and Sunwu Formations,the deposits with facies of braided river and braided river delta mainly developed in the Yuliangzi and Wuyun Formations,the deposits with facies of meandering river and meandering river delta mainly in the Yongancun and Taipinglinchang Formations,the deposits with facies of lake floor fan and lacustrine developed in all formations mentioned above.The sedimentational evolution from the Taoqihe to the Wuyun Formations showed a order of alluvial fan-fan-delta-lacustrine→meandering river-meandering river delta-lacustrine→braided river-braided river delta-lacustrine→alluvial fan-fan-delta-lacustrine,which comprehended the structural activity tended to gentle during Late Cretaceous-Paleocene,and the depressing became stronger again in Miocene-Pliocene.