1. Marine Sediment Classification
Classified by origin
Lithogenous – derived from land
Biogenous – derived from organisms
Hydrogenous– derived from water
Cosmogenous – derived from outer space
© 2011 Pearson Education, Inc.

2. Lithogenous Sediments
Also called terrigenous
Eroded rock fragments from land
Carried to ocean
Streams
Wind
Glaciers
Gravity
Greatest quantity around continental margins

3. Lithogenous Sediments
Reflect composition of rock from which derived
Coarser sediments closer to shore
Finer sediments farther from shore
Mainly mineral quartz (SiO2)
© 2011 Pearson Education, Inc.

4. © 2011 Pearson Education, Inc.
Biogenous Sediment
Hard remains of once-living organisms
Two major types:
Macroscopic
Visible to naked eye
Shells, bones, teeth
Microscopic
Tiny shells
Biogenic ooze
Mainly algae and protozoans
© 2011 Pearson Education, Inc.

5. Biogenous Sediment Composition
Two most common chemical compounds:
Calcium carbonate (CaCO3)
Silica (SiO2 or SiO2·nH2O)
© 2011 Pearson Education, Inc.

6. Silica in Biogenous Sediments
Tiny shells from diatoms and radiolarians generate siliceous ooze.
© 2011 Pearson Education, Inc.

7. Calcareous Ooze and the CCD
© 2011 Pearson Education, Inc.

8. Sea Floor Spreading and Sediment Accumulation
© 2011 Pearson Education, Inc.

9. Hydrogenous Marine Sediments
Minerals precipitate directly from seawater
Manganese nodules
Phosphates
Economically useful as fertilizer
Carbonates
Metal sulfides (Iron, Nickel, Copper, Zinc, Silver)
Associated with hydrothermal vents
Small proportion of marine sediments
Distributed in diverse environments
© 2011 Pearson Education, Inc.

10. Manganese Nodules
Fist-sized lumps of manganese, iron, and other metals
Very slow accumulation rates
Many commercial uses
Unsure why they are not buried by seafloor sediments

11. Distribution of Manganese Nodules
© 2011 Pearson Education, Inc.

12. © 2011 Pearson Education, Inc.
Evaporites
Evaporites
Minerals that form when seawater evaporates
Restricted open ocean circulation
High evaporation rates
Halite (common table salt) and gypsum
© 2011 Pearson Education, Inc.

13. © 2011 Pearson Education, Inc.
Mining Sea Salt
© 2011 Pearson Education, Inc.

14. Cosmogenous Marine Sediments
Macroscopic meteor debris
Microscopic iron-nickel and silicate masses)
Overall, insignificant proportion of marine sediments
© 2011 Pearson Education, Inc.

15. Marine Sediment Mixtures
Usually mixture of different sediment types
Typically one sediment type dominates in different areas of the sea floor.
© 2011 Pearson Education, Inc.

16. © 2011 Pearson Education, Inc.
Abyssal Clay
At least 70% clay sized particles from continents
Red from oxidized iron (Fe)
Abundant if other sediments absent
© 2011 Pearson Education, Inc.

17. Resources from Marine Sediments
Energy resources
Petroleum
Mainly from continental shelves
Gas hydrates
Sand and gravel (including tin, gold, and so on)
Evaporative salts
Phosphorite
Manganese nodules and crusts
© 2011 Pearson Education, Inc.