What is the difference between an Upper Plane Bed and a Lower Plane Bed?

This is a question for those adept to sedimentology.





In the context of sedimentary structures and flow regimes, what is the difference between upper and lower plane beds? Also, what sedimentary structure is commonly associated with an UPB and not with a LPB?|||It has been a few decades since I studied this, but I do remember a little. "Lower" and "upper" here refer to lower and upper flow regimes. Flows with low Reynolds numbers are referred to as "low flow regime" and those with hight Reynolds numbers as "high flow regimes."





Plane bedding can form in either flow regime. I forget how to distinguish between them.





http://en.wikipedia.org/wiki/Sedimentary鈥?/a>