why do heavier sediments deposited before smaller sediments
Erosion moves the sediment. Deposition deposits the sediments in a new place. Why does a river deposit heavier sediments first and lighter sediments later as it flows along? Heavier sediments are deposited first because the water has more energy and can carry heavier sediments before it slows down. As the water slows down, it carries less and lighter sediment. These lighter sediments are deposited after the heavier ones.