1. Marine Sediments
Chap 5

2. video

3. Lithogenous/Terrigenous Sediment
Derived from land
Origin from weathering/erosion
Mainly quartz (SiO2) – resistant to abrasion
Main constituent of continental shelf sediment can also be found in deep ocean

4. Sediment Texture
Big, cars go so slow, cool

5. Sediment Erosion, Transportation, Deposition

6. Sediment Maturity

7. Neretic Deposits (near shore lithogenous)
found along continental margins and islands – mainly lithogenous
Beach deposits – mainly quartz rich sands – but what ever is available
Continental Shelf deposits – carried by rivers
Turbidite deposits due to underwater avalanches – from turbidity currents –show graded bedding
Glacial Deposits – grinding by ice and trapped in glacial ice

8. Pelagic Deposits (open water lithogenous)
Fine grained material that accumulates on the ocean floor.
Abyssal Clay >70% clay sized particles from continent- due to lack of other particles
Contain oxidized iron making them red-brown or buff

9. Biogenous Sediment
Derived from hard parts of once-living organisms – algae and protozoans.
Macroscopic can be seen with eyes
Microscopic too small to be seen with unaided eye
Microscopic organisms produce small shells called tests and accumulates in the deep ocean to form ooze.

10. Composition Calcium Carbonate - CaCO3 (makes mineral calcite)
Silica SiO2.

11. Calcium Carbonate forms Calcareous Ooze
Foraminiferans are protozoans with porous CaCO3shells .
Coccolithophores are microalgae that are times smaller than diatoms, they are called nanoplankton. They have CaCO3 plates (cocoliths) that make up their shell. These decompose to form cocolith-rich CaCO3 ooze that can later lithify to form chalk and limestone.
Dover

12. Stromatolites
Lobate structures made of layers of carbonate from cyanobacteria at particular shallow depth.

13. Silica forms Siliceous Ooze
Silica biogenous ooze made mainly from planktonic algae called diatoms and a protozoans called radiolarians
Diatomaceous earth used in filters, abrasives, absorbents, glass. Also diatoms have a droplet of oil in them that have accumulated into petroleum deposits (ex: off California)
Silica dissolves is seawater and will only accumulate silica ooze where there is high production.

14. Calcite Compensation Depth -CCD
CaCO3 is saturate in warm shallow waters and can form sediments.
At deeper cooler waters CaCO3 is not saturated so does not form deposits after a certain depth – CCD.
Average CCD is 4500 m
Below 5000 m, calcareous ooze not usually found unless it was made at a higher depth and then covered before it’s present depth.
lysocline

16. Hydrogenous Sediment Derived from seawater
Chemical reaction cause minerals to precipitate out of sea water usually when there is a temperature or pressure change

17. Manganese nodules 5-20 cm lumps of Mn, Fe and other metals
Found on deep ocean floor 100/m2

18. Phosphates
Phosphate bearing compounds found on rocks and nodules on the continental shelf and banks at depths < 1000m.
Used as fertilizer and other agricultural proposes

19. Carbonates
Aragonite and calcite are the two most important carbonate sediments
Aragonite has a different crystalline structure and is less stable and changes into calcite over time.
Biogenous in origin, aragonite crstals can form hydrogenously by precipitating directly from seawater.
Oolites are small calcite spheres that form in shallow tropical waters with high CaCO3 concentrations.

20. Metal Sulfides Made by black smokers at hydrothermal vents
Iron, nickel, copper, zinc, silver and other metals.

21. Evaporites minerals
In restricted circulation areas where evaporation is high – seawater becomes saturated with minerals and the minerals precipitate out.
Collectively called salts, some evaporites may taste salty because of NaCl and other do not like calcium sulfate minerals anhydrite (CaSO4) amd gypsum (and H20)

22. Cosmogenous Sediment Extraterrestrial origin
Spherules = microscopic, usually once molten basalt from impact events, forms tektites
Although 90% of tektites are destroyed by frictional heating with the atmosphere, 300,000 metric tons/year reach Earth
Meteor = macroscopic, impact material made of rock (chondrites) or iron and nickel (irons) settle out around impact sites.

23. % of Pelagic Sediments
47.7% Carbonate
14.2% Siliceous
38.1% Abyssal