Meaning of progradation

pro•gra•da•tion

Pronunciation: (prō"grā-dā'shun), [key]
— n. Geol.
  1. seaward growth of a beach, delta, fan, etc., by progressive deposition of sediment by rivers or shoreline processes.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.