本文研究了河流沉积构造、结构、石英颗粒表面特征和沉积相特征,并提出组成曲流点坝标志的两个重要要素及沉积模式。有助于认识古代岩相中点坝层序和对此模式。

The present meandering streams in Hebei Plain, with I.28-I.79 sinuosity, are mixing loaded rivers.Usually, there is an erosional surface and a fluvial stagnant phase sediment of pebbles and muddy nodules at the base of the point-bar. Above it, sediment developed fining upward trend of the grainsize, and became silt with plant roots at the top. The depositional structures were mainly made up of trough-cross beddings, accompanied with parallel、horizontal、climbing and ripple beddings, occasionally tabular beddings, Sametimes, different deformational structures were also found.The basic units of point-bars in meandering streams are inclined bodies, One point-bar is probably composed of several diagonal sedimentary bodies. Every body had the fundamental characters of the point-bar. Every two adjacent bodies bordered each other with an inclined erosion surface. It is often situated in the upper-middle part, sometimes reached to the base of the sediment, A mark of mud or muddy silt cover on the sedimentary body is usually found, which shows significant change of the streamflow.