1. Origin and Distribution of Marine Sediments What’s all that squishy muck at the bottom of the ocean? What can we learn from it? What’s all that squishy muck at the bottom of the ocean? What can we learn from it?

2. Marine Sediments are: FParticles of various sizes derived from a variety of sources that are deposited on the ocean floor FA vast “library” recording geologic, oceanographic and climatic conditions FRemarkably complete compared to land FParticles of various sizes derived from a variety of sources that are deposited on the ocean floor FA vast “library” recording geologic, oceanographic and climatic conditions FRemarkably complete compared to land

3. Where do these come from? FInputs are: -- rivers -- atmosphere -- surface waters -- volcanoes (both on land and submarine) -- deep ocean water -- outer space

4. Classifications FBy Size Clay -- Silt -- Sand -- Pebble -- Cobble 0.001 mm 1 mm 100 mm F Effects of water velocity on transport: rivers and near-shore vs open ocean FBy Size Clay -- Silt -- Sand -- Pebble -- Cobble 0.001 mm 1 mm 100 mm F Effects of water velocity on transport: rivers and near-shore vs open ocean

5. Sediment Transport  Fluid velocity determines the size of the particles that can be moved

6. Size Sorting

7. Classifications FBy Origin Terrigenous -- from land Biogenous -- from life in the oceans Hydrogenous -- precipitated from water Cosmogenous -- extraterrestrial

8. Terrigenous sediments (from land) FRivers FWinds (eolian) FGlaciers (ice-rafted debris, IRD) FTurbidites FSea level changes FRivers FWinds (eolian) FGlaciers (ice-rafted debris, IRD) FTurbidites FSea level changes

9. River sediment loads ( units 10 6 tons/yr )

10. Glacial (Ice-rafted debris)

11. Turbidites uRapidly-accumulated terrestrial sediments uEarthquake-triggered submarine avalanches uHigh velocity (~50 mph!), erosive events uGood examples preserved on Mary’s Peak uRapidly-accumulated terrestrial sediments uEarthquake-triggered submarine avalanches uHigh velocity (~50 mph!), erosive events uGood examples preserved on Mary’s Peak

12. Turbidites (submarine avalanches)

13. Sea Level Changes

14. Biogenous sediments (from living things) FCalcareous (CaCO 3 ) Foraminifera -- animals Coccolithophores -- plants FSiliceous (SiO 2 ) Radiolaria -- animals Diatoms -- plants FCalcareous (CaCO 3 ) Foraminifera -- animals Coccolithophores -- plants FSiliceous (SiO 2 ) Radiolaria -- animals Diatoms -- plants

15.  m = micron = millionth of a meter!

19. Productivity = skeletons and soft tissue uAccumulation depends on production and preservation uSiO 2 is preserved everywhere uCaCO 3 is variable, depending on P, T, pH uAccumulation depends on production and preservation uSiO 2 is preserved everywhere uCaCO 3 is variable, depending on P, T, pH

20. Carbonate Compensation Depth

21. FThe depth at which carbonate input from the surface waters is balanced by dissolution in corrosive deep waters FIn today’s ocean this depth (CCD) varies between 3 km (polar) and 5 km (tropical) FThus, accumulation rates vary a lot! FThe depth at which carbonate input from the surface waters is balanced by dissolution in corrosive deep waters FIn today’s ocean this depth (CCD) varies between 3 km (polar) and 5 km (tropical) FThus, accumulation rates vary a lot!

22. Accumulation Rates for Oozes FProductivity  reproduction of planktonic organisms FPreservation  silica dissolves only very slowly  calcium carbonate varies with depth FRates are variable: <1 to 15mm/1000 yr FProductivity  reproduction of planktonic organisms FPreservation  silica dissolves only very slowly  calcium carbonate varies with depth FRates are variable: <1 to 15mm/1000 yr

23. Coastal waters are often highly productive, with abundant planktonic organisms thriving in the surface waters. Why then are biogenous oozes rarely found nearshore??

24. the large input of terrigenous sediment to the continental margin overwhelms the biogenous component in the sediment.

25. Hydrogenous (from sea water) FMetalliferous sediments at spreading ridges -- “black smokers” FManganese nodules FEvaporites -- Salt deposits FMetalliferous sediments at spreading ridges -- “black smokers” FManganese nodules FEvaporites -- Salt deposits

26. baseball to bowling ball size!

27. Cosmogenous (from outer space) FMeteorites and comets

28. Sediment Accumulation

29. Sediment succession

30. Distribution of Marine Sediments