If water is the transport medium of sediment, the grain size of sedimentary deposits most closely indicates the _______.
I've narrowed down the possible choices to these two (the other two were obviously wrong):
1. Average velocity of the water from the time of erosion until deposition.
2. Velocity of the water at the moment the sediment settled to the bottom.
Either one makes sense to me, in light of what we talked about in class. The Hjulstrom diagram, which was sort of the basis for this lesson, has both erosion and deposition values, so my initial instinct was to go with the first answer. Also, sediment can reach the bottom and still move along it, so it seems that the velocity of the water at the moment the sediment settled to the bottom would only account for grains that were actually picked up and dropped to the bottom. Of course, that is only one way in which sediment moves due to current. Once dropped to the bottom, grains can continue to roll along the bottom and be transported.
Hmmm...I may have just figured this one out. Yay, blog!
NOTE: This is a take-home test in which I have been given full permission to consult books/other people. I'd prefer it if I wasn't given the answer...just some discussion that might help me come to it on my own. Thanks!