There are several types of sediments found in oceans. Terrigenous sediments are derived from land sources through rivers, glaciers, wind, and coastal erosion. Biogenous sediments are derived from plants and animals, consisting mainly of shells and bones. They form oozes, including calcareous oozes made of calcium carbonate from organisms like foraminifera and coccolithophores, and siliceous oozes made of silicon from diatoms and radiolaria. Hydrogenous sediments form through chemical reactions in the ocean and include manganese nodules, phosphorites, and deposits near hydrothermal vents. Sediment size, sorting, and location affect conditions for organisms.

1. Sediments in the Oceans

2. sediment - matter that has been deposited by some natural process

3. smaller – easier for currents to move larger – harder for currents to move Sediment Sizes large small

4. marine sediments classified as: oceanic (pelagic) – found in open ocean further away from land neritic – found in waters above continental margins closer to land - coastal

5. sediment types *terrigenous - derived from land *biogenous - derived from plants and animals hydrogenous (authigenic) – form from chemical reactions in the ocean cosmogenous - from outer space *most common

6. derived from land rock fragments volcanic ash blown dust broken down by weathering (erosion) Terrigenous Sediment

7. sources: rivers - biggest contributors glaciers wind blown dust coastal erosion volcanic debris groundwater Terrigenous Sediment

8. turbidite – like an underwater landslide – carries terrigenous sediment down cont. slope Terrigenous Sediment

9. Terrigenous Sediment dust from the Sahara Desert

10. Biogenous Sediment derived from plants and animals mostly shells, some bones

11. Biogenous Sediment ooze – very fine sediments at least 30% biogenous in origin found in deep sea off continental margins build up very slowly two main types: calcareous ooze and siliceous ooze

12. Biogenous Sediment Calcareous Ooze made of calcium carbonate (CaCO 3 ) - chalky dissolves in very deep waters includes: foraminifera (like ameba w/ shell) coccolithophores (algae w/ shell) pteropods (small drifting snails) foraminifera coccolithophores pteropods

13. Coccolithophores and a coccolithiphore bloom near England

14. Biogenous Sediment The White Cliffs of Dover made of calcareous ooze – basically chalk

15. Biogenous Sediment Siliceous Ooze made of silicon (glass) deeper than calcareous oozes and polar regions includes: diatoms (algae) radiolaria (like ameba w/ shell) diatoms radiolaria

16. Hydrogenous Sediment also called authigenic sediments form from chemical reactions in the ocean very small percentage of ocean sediments

17. Hydrogenous Sediment Manganese Nodules: golf ball size chunks of manganese and iron found in deep sea thought would be economically valuable one day

18. Hydrogenous Sediment Phosphorites: like manganese nodules, but mostly phosphorus may be important some day for fertilizer

19. Hydrogenous Sediment Hydrothermal Vents: like underwater hot springs at mid-ocean ridges form metal sulfides

20. Hydrogenous Sediment Evaporites: salts that precipitate (form solid) as water evaporates from an isolated arm of the ocean

21. Cosmogenous Sediment from outer space found in trace amounts – least common examples: dust from outer space meteorite debris microtektites – crustal material that exits earth’s atmosphere during meteor impact and then falls back to earth – melts forming glassy teardrops

22. Where types of sediment are found:

23. sediments can be: well sorted – all one size poorly sorted – many sizes together affects: amount of water between sediment grains oxygen level types of organisms that can live there