Deltas form wherever rivers encounter standing bodies of water such as lakes
or oceans. The sudden decrease in energy causes the river to drop its sediment
load. Deltaic deposits therefore become finer grained the farther out into the
lake or ocean (distal edge). Across the delta, they are coarsest in the
distributary channels and finest away from the channels. Many deltaic deposits
resemble lake or shallow marine
deposits at their distal margins and river deposits at
their proximal margins.
|Niger Delta, Nigeria|
|Shatt al Arab Delta|
|Sediment deposited from Puyallup River, Commencement Bay, Tacoma, WA.||Distributaries near mouth of Mississippi Delta, Louisiana|
|Delta building into lake. SE Alaska.||Delta and alpine lake. Banff National Park, Alberta||Delta and alpine lake. Grand Teton National Park, Wyoming|
A more detailed explanation of sedimentological features associated with deltaic environments can be found here.