Sedimentary facies types and evolution of the Sunwu-Jiayin Basin in northern Heilongjiang province
Yang Jianguo1,2, Shao Zhaoyi3, Wu Heyong2, Liu Junlai1
1. State Key Laboatory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083; 2. Exploration and Development Reserch Institute of Daqing Oilfield Company Ltd., Daqing, Heilongjiang 163712; 3. Daqing Institute of Petroleum, Daqing, Heilongjiang 163318
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.