2. LITHOGENOUS SEDIMENT- Pelagic
"Red Clay" -- fine terrigenous dust + volcanic ash
Settles eventually, everywhere
Dominant only where other types absent

4. OCEAN SEDIMENTS Cosmogenous Biogenous Hydrogenous
Class #12
OCEAN SEDIMENTS
Cosmogenous
Biogenous
Hydrogenous

5. OCEAN SEDIMENTS
Sources (origins)
Distribution
TYPES (BY SOURCE):
Lithogenous ("rock-derived')
Biogenous ("life-derived")
Hydrogenous ("water-derived")
Cosmogenous ("cosmic-derived")

6. Sediment Types

7. COSMOGENOUS SEDIMENTS
Micro-meteorites
silicates, iron metals
very small quantities (noticeable in red clay)

8. Sediment Types

9. BIOGENOUS SEDIMENTS -- produced directly by living organisms
Large fragments: warm, shallow areas
clams, corals
Very thick accumulations in some places

12. CaCO3 = calcium carbonate
2) Everywhere: Tiny particles produced...
Pelagic sediment
Shells or skeletons of microplankton
Biogenous "oozes” (>30% biogenous material)
Calcareous ooze
CaCO3 = calcium carbonate
Siliceous ooze
SiO2 = silica (+ H2O)

14. Calcareous ooze: Coccoliths + Foraminifers

15. Siliceous ooze: Diatoms and/or Radiolarians

16. Single –celled organisms that make tiny shells/skeletons that settle to the ocean bottom (biogenous seds).
Material Produced
Algae
Protozoans
CaCO3
Coccolithophores
Foraminifera
SiO2
Diatoms
Radiolarians

18. Where do we find biogenous oozes?
1. Siliceous oozes
Controlled by nutrients: High Si, N, P, and Fe causes high productivity; upwelling zones
2. Calcareous particles- almost everywhere, but in some places they are dissolved before they get to the bottom

20. Where do we find biogenous oozes?- MORE
2. CaCO3 particles dissolve quickly below the “Carbonate Compensation Depth” (CCD)
Atlantic: ~ 4,000 m depth
Pacific: ~ ,500 m depth
SiO2 particles dissolved more slowly (everywhere)
Siliceous ooze can collect in deep areas
But…Must accumulate quickly- high productivity areas
3. NOT dominant near continents, usually:
Too much terrigenous sediment

22. Sediment Types

23. CaCO3 is very important
chemically

24. HYDROGENEOUS SEDIMENTS:
precipitation of dissolved elements in water
Evaporites
Evaporation in isolated basins
E.g., Mediterranean Sea 6 M.Y. ago
Precipitation of "salts"
NaCl (halite)
CaSO4• 2H2O (gypsum)

27. Salt Mine under Detroit: Shallow sea over 400 m.y. ago

29. 2. Manganese nodules and crusts
Mn + Fe oxides (+ Cu, Co, Ni)
In deep ocean basins and along mid-ocean ridges
Origin: -- chemical reaction between oxygen in water and dissolved Mn +Fe
Mn + Fe come mostly from sediments and hydrothermal vents

33. 3) Phosphate minerals
P released when organic matter degrades- Minerals precipitated
On Cont. shelves
4) Metal sulfides from hydrothermal vents
Collect on ocean floor
Metal-rich (gold, copper)

34. Fig. 4.18