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

"Red Clay""Red Clay" -- fine terrigenous dust + volcanic ash -- fine terrigenous dust + volcanic ash–Settles eventually, everywhereSettles eventually, everywhere–Dominant only where other types absentDominant only where other types absent

LITHOGENOUS SEDIMENT- PelagicLITHOGENOUS SEDIMENT- Pelagic

Class #12

OCEAN SEDIMENTSCosmogenousBiogenousHydrogenous

OCEAN SEDIMENTSOCEAN SEDIMENTSSources (origins)Sources (origins)DistributionDistribution

TYPES (BY SOURCE):TYPES (BY SOURCE):Lithogenous ("rock-derived')Lithogenous ("rock-derived')Biogenous ("life-derived")Biogenous ("life-derived")Hydrogenous ("water-derived")Hydrogenous ("water-derived")Cosmogenous ("cosmic-derived")Cosmogenous ("cosmic-derived")

Sediment TypesType Source Areas Examples

Lithogenous Eroded RockVolcanoesAirborne Dust

EverywhereSandsMudsRed Clay

Biogenous LivingOrganisms

Everywhere PlantsCoralsShellsOozes

Hydrogenous ChemicalPrecipitation

NeriticPelagic

Mn NodulesPhosphates

Cosmogenous Space Pelagic Micro-Meteorites

Micro-meteoritesMicro-meteorites silicates, iron metalssilicates, iron metalsvery small quantities (noticeable in red very small quantities (noticeable in red clay)clay)

COSMOGENOUS SEDIMENTSCOSMOGENOUS SEDIMENTS







NeriticPelagic



1)1) Large fragments: warm, shallow areasLarge fragments: warm, shallow areas– clams, coralsclams, corals– Very thick accumulations in some placesVery thick accumulations in some places

BIOGENOUS SEDIMENTS -- produced BIOGENOUS SEDIMENTS -- produced directly by living organismsdirectly by living organisms

2) Everywhere: Tiny particles produced...2) Everywhere: Tiny particles produced...– Pelagic sediment Pelagic sediment – Shells or skeletons of microplanktonShells or skeletons of microplankton– Biogenous "oozes” (>30% biogenous material)Biogenous "oozes” (>30% biogenous material)

• Calcareous ooze Calcareous ooze – CaCOCaCO33 = calcium carbonate = calcium carbonate

• Siliceous ooze Siliceous ooze – SiOSiO2 2 = silica (+ H= silica (+ H22O)O)

Calcareous ooze: Coccoliths + Foraminifers

Siliceous ooze: Diatoms and/or Radiolarians

Material Produced

Algae Protozoans

CaCO3 Coccolithophores Foraminifera

SiO2 Diatoms Radiolarians

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

1. 1. Siliceous oozesSiliceous oozes• Controlled by nutrients: High Si, N, P, and Fe Controlled by nutrients: High Si, N, P, and Fe causes high productivity; causes high productivity; upwelling zonesupwelling zones

2. Calcareous particles- almost everywhere, but in 2. Calcareous particles- almost everywhere, but in some places they are dissolved before they get to some places they are dissolved before they get to the bottomthe bottom

Where do we find biogenous oozes?Where do we find biogenous oozes?

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 Must accumulate quickly- high productivity

areasareas

3. NOT dominant near continents, usually:Too much terrigenous sediment

Where do we find biogenous oozes?- MORE







NeriticPelagic



CaCOCaCO33 is very important is very important

chemicallychemically

HYDROGENEOUS SEDIMENTS:HYDROGENEOUS SEDIMENTS:precipitation of dissolved elements in waterprecipitation of dissolved elements in water

1.1. EvaporitesEvaporitesEvaporation in isolated basinsEvaporation in isolated basins

•E.g., Mediterranean Sea 6 M.Y. agoE.g., Mediterranean Sea 6 M.Y. ago• Precipitation of "salts" Precipitation of "salts"

•NaCl (halite) NaCl (halite) •CaSOCaSO44• 2H• 2H22O (gypsum)O (gypsum)

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

2. Manganese nodules and crusts2. Manganese nodules and crusts• Mn + Fe oxides (+ Cu, Co, Ni) Mn + Fe oxides (+ Cu, Co, Ni) • In deep ocean basins and along mid-ocean In deep ocean basins and along mid-ocean

ridgesridges

• Origin: -- chemical reaction between Origin: -- chemical reaction between oxygen in water and dissolved Mn +Feoxygen in water and dissolved Mn +Fe

• Mn + Fe come mostly from sediments and Mn + Fe come mostly from sediments and hydrothermal ventshydrothermal vents

3) Phosphate minerals3) Phosphate minerals• P released when organic matter P released when organic matter

degrades- Minerals precipitateddegrades- Minerals precipitated• On Cont. shelvesOn Cont. shelves

4) Metal sulfides from hydrothermal vents4) Metal sulfides from hydrothermal vents• Collect on ocean floorCollect on ocean floor• Metal-rich (gold, copper)Metal-rich (gold, copper)

Fig. 4.18

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