Sets, Cross-Sets, a beds
-lamina are bounded by set boundaries
-accumulation of several ripples, migrating one over another is a coset
coset: effectively equivalent to a bed
Current Generated Ripples
f deposition rate is higher, then you can get net deposition on the soft side of a ripple.
-Rapid deposition with high sedimentation rate
-Climbing ripple stratification….shows at the top
-The nature of the foresets are formed from avalanches. The form of those foresets is different in
-Velocity and bed shear stress control the shape and slope of foreset laminae.
-The ratio of depth of stream flow to the depth of the basin[depth ratio] also controls shape and slope.
-Dunes: have a wavelength of 1-10m, ripple index similar to that of ripples
-just a different scale of bedform than ripples
-a different scale of nature
-Dunes are entirely different entities than dunes
-Distinguishing between ripple formation and dune formation is done by experimentation
-A physical theory comprehensively explains what happens.
-Tidal dunes are a type of dune, about 1m high and 10m long, it is a type of subaqueous dune.
-2D dunes create planar CB, 3D dunes create trough CB
Bedform stability diagram
-Lower flow velocities on the bedform