(完整版)沉积岩构造课件2.ppt

沉积岩构造(sedimentary structure)
一、物理成因构造
在搬运和沉积时，或者沉积之后不久，在流体流动、重力等物理因素作用下产生
流动成因构造、同生变形构造、暴露成因构造
1. 流动构造:
由于介质的流动十多厘米，长数厘米至数十厘米
可以孤立或成群出现，顺着水流方向排列，浑圆突起端迎着水流方向
形成过程：泥质沉积物表面上凹凸不平，导致水流的分离和涡流的产生。涡流在松软的泥质沉积物面上冲刷出凹槽。其后，凹槽被砂充填，成为砂岩层底面上的槽铸型——槽模(flute casts)
纵向脊与沟 (longitudinal ridge and furrow):由一系列平行于水流方向延伸的脊与沟紧密间互排列所组成的构造。
横向冲刷痕(transverse scour mark):
垂直于水流方向排列的、一系列相互平行的、浅而不对称的冲沟。
可能与水流在泥质沉积物表面流动时所产生的剪切现象相结合的侵蚀作用有关。
障碍冲刷痕 (obstacle-scour mark) :
水流在位于沉积物表面上的障碍物周围发生侵蚀和沉积所形成的构造，也常称为水流新月形构造 (current crescent)。
Channel Cast：A flow of coarse material cut into underlying mud, forming a channel, and eventually hardened into rock
Channelized bedding. Erosive scours that backfill with sand may give rise to isolated channelized sandbodies
压刻痕
水流所携带的物体在松软的沉积物表面上运动时所刻蚀或刻划出来的痕迹称为压刻痕或工具痕(tool mark).
沟痕(模) (groove mark / cast)
V形痕 (chevron mark)
戳痕 (prod mark)
弹跳痕 (bounce mark)
刷痕 (brush mark)
跳跃痕 (skip mark)
滚动痕 (roll mark)
大型滚动痕 (large-scale slide mark)
其它表面痕迹
细流痕(rill mark)
冲淤构造(scour and fill structure)
冲蚀构造(washout structure)
冲流痕(swash mark)
剥离线理(parting lineation)
水位痕(water level mark)
皱痕(wrinkle mark)
粘附波痕和粘附瘤(adhesion ripple and adhesion warts)
Scour-and-Fill Structures：Here flows of coarse sediment repeatedly eroded, then filled channels (scours) in the underlying sediment. The coarse fill was itself scoured and filled.
Hummocky Cross-Bedding：Hummocky cross-bedding is a distinctive bedding pattern that is a sign of ancient storms, like hurricanes
Hummocky cross-bedding is more formally known as hummocky cross-stratification and often given the abbreviation HCS
a sandy seafloor near the beach but not too near, roiled by a major storm with more sand pouring in from the beach. Piles of sand at least a meter high (hummocks) are built up and travel across the bottom, sand being eroded off the upstream side and dumped on the leading downstream side. The whole seafloor is built up with a permanent new coat of sand, bearing the internal marks left by