Marine geology

Terrigenous and Pelagic The two main classifications of marine sediments are terrigenous and pelagic.. Terrigenous sediments are derived from land and found near shore.. Pelagic sedimen

Marine Geology

Marine Sediments

Terrigenous and Pelagic

The two main classifications of marine sediments are

terrigenous and pelagic Terrigenous sediments are derived from land and found near shore Normally, the go from

rivers to costal regions Pelagic sediments settle slowly out

of the water column and are deposited all over the ocean Pelagic sediments are mostly associated with deep sea areas

The further away from land the smaller the sediment size.

Terrigenous sediments are usually classified by their size Sediment grain size depends on the energy of the depositional environment, with more energy leading to larger grain sizes A steep mountain stream, where water flows quickly downhill, might have very large grain sizes, from gravel to pebbles A river bed, where currents are slower, might be filled with sand Beaches, where waves crash

against the shore and the surf runs in and out, often have

sand-sized particles as well Farther offshore, where the water is less

active, terrigenous materials will be smaller or clay size particles

Pelagic sediments are classified by composition, not size The size of pelagic sediments is uniformly pretty small There are four main

compositional groups for marine sediment which are Lithogenous,

Biogenous, Hydrogenous, and Cosmogenous.

Lithogenous - This is sediment that is derived from rocks.

Biogenous - This is sediment that is derived from living organisms.

Hydrogenous - This sediment is derived from the ions in seawater.

Cosmogenous -The Earth is continually being bombarded from space by meteors and cosmic dust.