Marine Sediments
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Marine sediments provide a historical record of Earth's changes and consist of various origins including lithogenous, biogenous, hydrogenous, and cosmogenous materials. These sediments are formed from eroded rock particles that are transported to and deposited in oceans, allowing oceanographers to study past marine and climatic changes. Key types of deposits include neritic and pelagic sediments, characterized by their location and particle size.
Marine Sediments
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- 2. Marine sediments contain a record of Earth history. Marine sediments provide a variety of important resources. Marine sediments have a variety of origins. © 2011 Pearson Education, Inc.
- 3. How is sediment formed? Eroded rock particles and fragments Transported to ocean Deposit by settling through water column Oceanographers decipher Earth history through studying sediments. © 2011 Pearson Education, Inc.
- 4. Paleoceanography – study of how ocean, atmosphere, and land interactions have produced changes in ocean chemistry, circulation, biology, and climate Marine sediments provide clues to past changes. © 2011 Pearson Education, Inc.
- 5. Classified by origin Lithogenous – derived from land Biogenous – derived from organisms Hydrogenous or Authigenic – derived from water Cosmogenous – derived from outer space © 2011 Pearson Education, Inc.
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- 7. Eroded rock fragments • Produced by from land weathering Also called terrigenous – Breaking of rocks into smaller pieces Reflect composition of rock from which derived © 2011 Pearson Education, Inc.
- 8. Small particles eroded and transported Carried to ocean Streams Wind Glaciers Gravity Greatest quantity around continental margins © 2011 Pearson Education, Inc.
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- 11. Proportional to energy of transportation and deposition © 2011 Pearson Education, Inc.
- 13. Neritic Shallow-water deposits Close to land Dominantly lithogenous Typically deposited quickly Pelagic Deeper-water deposits Finer-grained sediments Deposited slowly © 2011 Pearson Education, Inc.
- 14. Beach deposits Mainly wave-deposited quartz-rich sands Continental shelf deposits Relict sediments Turbidite deposits Graded bedding Glacial deposits High latitude continental shelf Currently forming by ice rafting © 2011 Pearson Education, Inc.
- 15. Fine-grained material Accumulates slowly on deep ocean floor Pelagic lithogenous sediment from Volcanic ash (volcanic eruptions) Wind-blown dust Fine-grained material transported by deep ocean currents © 2011 Pearson Education, Inc.
- 16. 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. Hard remains of once-living organisms Two major types: Macroscopic Visible to naked eye Shells, bones, teeth Microscopic Tiny shells or tests Biogenic ooze Mainly algae and protozoans © 2011 Pearson Education, Inc.
- 18. Two most common chemical compounds: Calcium carbonate (CaCO3) Silica (SiO2 or SiO2·nH2O) © 2011 Pearson Education, Inc.