1 / 35

"Red Clay" -- fine terrigenous dust + volcanic ash Settles eventually, everywhere

LITHOGENOUS SEDIMENT- Pelagic. "Red Clay" -- fine terrigenous dust + volcanic ash Settles eventually, everywhere Dominant only where other types absent. Class #12. OCEAN SEDIMENTS Cosmogenous Biogenous Hydrogenous. OCEAN SEDIMENTS Sources (origins) Distribution TYPES (BY SOURCE):

isaura
Télécharger la présentation

"Red Clay" -- fine terrigenous dust + volcanic ash Settles eventually, everywhere

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


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

  2. Class #12 OCEAN SEDIMENTS Cosmogenous Biogenous Hydrogenous

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

  4. Sediment Types

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

  6. Sediment Types

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

  8. 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)

  9. Calcareous ooze: Coccoliths + Foraminifers

  10. Siliceous ooze: Diatoms and/or Radiolarians

  11. Single –celled organisms that make tiny shells/skeletons that settle to the ocean bottom (biogenous seds).

  12. 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

  13. 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 - 1,500 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

  14. Sediment Types

  15. CaCO3 is very important chemically

  16. 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)

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

  18. 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

  19. 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)

  20. Fig. 4.18

More Related