How can you explain a sediment deposit that contains unlayered and randomly sorted material at the bottom and layered, well-sorted material at the top?

1 Answer
Jul 6, 2017

The bottom layers were deposited quickly while the top layers were deposited much more slowly.

Explanation:

When sediment is deposited slowly the heaviest particles settle out first, then the next heaviest, and the next, etc. When sediment is laid down quickly or stirred as it settles these particles would not settle is obvious layers.