1. Marine Sedimentation What is it and where does it come from?

2. Table 5-1, p. 103

3. Bottom of the Ocean Floor (Antarctica)

4. How do we know/How do we get it?

6. Ice samples

8. River inputs (sedimentation)

9. Atmospheric Inputs

10. Dust input

11. Based upon water depth, the ocean environment can be divided into: –the shelf shallow and near a terrigenous source –the deep ocean basin deep and far from a terrigenous source

12. Shelf Sedimentation

13. Shelf sedimentation is strongly controlled by: –Tides –Waves –Currents Their influence decreases with water depth. Shoreline turbulence prevents small particles from settling in the shallow water. Particle size decreases seaward for recent sediments.

14. Geologic controls of continental shelf sedimentation must be considered in terms of a time frame. For a time frame up to: –1000 years, waves, currents and tides control sedimentation. –1,000,000 years, sea level lowered by glaciation controls sedimentation and cause rivers to deposit their sediments at the shelf edge and onto the upper continental slope. –100,000,000 years, plate tectonics determines the type of margin that develops and controls sedimentation. 4-2 Sedimentation in the Ocean

15. What’s in there? Forams Coccoliths Radiolarians (and other Protozoans) Diatoms and other Phytoplankton (shells) Fecal Pellets and “Dead” things (marine snow)

16. Major pelagic sediments in the ocean are red clay and biogenic oozes. “Marine Snow” Foraminifera Diatoms

17. Foram

18. Coccolith

19. Radiolarians

20. Diatoms

21. Fecal Pellet

22. What do you get? …What geologic structures? and where?

23. 100 mya - Lithified Coccolith Cliffs (Dover, England)

24. Fig. 5-12, p. 111

25. Global Deep-Sea Deposits Sedimentation Rates

27. If influx of terrigenous sediment is low and the water is warm, carbonate sediments and reefs will dominate. Distribution of Carbonate Shelves

28. Deep-sea Sedimentation has two main sources of sediment: –External – terrigenous material from the land –Internal – biogenous and hydrogenous from the sea.

29. Deep-Sea Sedimentation