What do ripple marks tell you about the ater that created them?
What does height of ripple marks tell about the water that created them?
How do mudcracks form?
What do ancient mud cracks suggest about the environment in which they formed?
2006-10-17 15:46:29 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
"Ripples are undulations of the sediment surface produced as wind or water moves across sand. Ripples which form in unidirectional currents (such as in streams or rivers) tend to be asymmetrical. Crests of asymmetrical ripples may be straight, sinuous, or lobe-like, depending on water velocity. Asymmetrical ripples have a steep slope on the downstream side, and a gentle slope on the upstream side. Because of this unique geometry, asymmetrical ripples in the rock record may be used to determine ancient current directions or paleocurrent directions. In waves or oscillating water, symmetrical ripples are produced. Crests of symmetrical ripples tend to be relatively straight, but may bifurcate (or fork)."
"Mudcracks are a polygonal pattern of cracks produced on the surface of mud as it dries. The mud polygons between the cracks may be broken up later by water movement, and redeposited as intraclasts (particularly in lime muds)."
(There are pictures at the source link!)
2006-10-17 15:58:49 · answer #1 · answered by wdmc 4 · 0⤊ 0⤋
what evaporated from cayey/silty soil, leaving behind crack shape.
it may suggest Dry/Famine conditions in ancient time.
2006-10-17 15:53:01 · answer #2 · answered by dilemma 2 · 0⤊ 0⤋