颗粒流沉积过程中的同沉积冲刷变形构造

Syndepositional scoured deformation structure in grain flow deposition

济阳拗陷坨147井沙三段岩心的颗粒流沉积中,存在一系列特殊的同沉积期变形构造,包括:颗粒流向下侵蚀,并沿纹层面挤入到下伏油页岩层中,形成伸长状的小砂体;砂楔上部的泥页岩薄层在后续流体的冲刷下向后翻卷变形;翻卷片被撕裂、断开混入到颗粒流中,并被流体拖曳变形;变形体被继续拖曳形成脉状分叉的拖曳痕。上述几种现象可以构成一个连续的变化序列,与油页岩的薄互层和颗粒流的流体是形成上述连续变形构造的重要条件。对这种现象的研究,有助于进一步了解重力流的冲刷、沉积过程。

A series of syndepositional deformation structures were developed in grain flow deposition of the third member of the Shahejie formation of well Tuo147, Jiyang depression ,including : small extended-sharpe sand (called sand wedge) formed by scouring of grain flow and squeezing of sand into underlying oil shale along liminate; turned-over deformation of thin-layered oil shale (called turned-over slice) due to scouring of later flow; deformation produced by tearing up of turned-over slice, and then wrapping into grain flow and being dragged by vein-like branch formed by continous dragging of the deformation body.These structures can form a continuous deformation sequence. The important factors to form these structure are thin layers of oil shale and grain flow .