合肥盆地东北缘白垩纪地层特征及沉积环境分析

合肥盆地东北缘白垩纪地层广泛发育、地层较完整，自下而上为：新庄组、邱庄组和张桥组等3个岩石地层单位。白垩纪在合肥盆地均为陆相沉积，沉积相的纵、横向变化均较大，有洪积扇、冲积扇、河流、风成、浅湖和深湖相。合肥盆地东北缘的形成和演化受郯庐断裂所控制，早白垩世早期，郯庐断裂左行平移，产生北东向拉分，形成断、坳陷盆地，至早白垩世晚期，郯庐断裂北西—南东向伸展，形成地堑式断陷盆地。

THE FEATURES AND SEDIMENTARY ENVIRONWENTAL ANALYSIS OF THE CRETACEOUS STRATA ON THE NORTHEAST MARGIN OF HEFEI BASIN

Cretaceous strata are developed broadly on the northeast margin of Hefei basin with complete sequence upward as early Cretaceous Xizhuang Formation and late Cretaceous Qiuzhuang Formation and Zhangqiao Formation. The measurement of stratigraphical profiles and 1:50000 scale regional survey mapping show that the Cretaceous sediments are all of terrestrial facies with great change in both vertical and horizontal directions where pluvial fan, alluvial fan, stream, eolian, shallow and deep lake facies occur. The formation and evolution of the northeast margin of Hefei basin is controlled by the Tan-Lu Fault. In the beginning of early Cretaceous, the left - handed strike - slip faulting caused northeast pulling -apart and formed rift and down - warped basin. and the NW - NE - trending extension of the fault resulted in graben - type rift basin by the late period of early Cretaceous.