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Marine Sediments
Neritic & Pelagic: based on Location
Terrigenous or Lithogenous, Biogenous, Authigenic &
Hydrogenous: based on Source and Chemistry
Marine Sediments: why important?
http://geology.uprm.edu/Morelock/GEOLOCN_/dpseaterrig.htm
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• The building of the continents, marine strata
Paleo-oceanography: skeletal remains used to
interpret history of life and past current patterns,
ie. Antarctic Circumpolar Current (ACC).
• Variations of climate and seawater temperature
over time: 18O:16O
• Paleo-geography of ocean lithosphere / SFS
• Biomedical potential
• Seabed Resources: Phosphorites, Sulfur,
Sand & Gravel, Coal, Oil & Gas and Methane
Hydrates
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Shallow to Intermediate Marine, 540my
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Planktonic Organisms
Seabed Resources
(sand and gravel)
http://www.mii.org/Minerals/photosandgr.html
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Seabed Resources
(coal, oil and natural gas)
• Japan is currently mining undersea coal deposits
• Oil/Gas represent >95% of the value of all resources
extracted from seafloor or below.
• In 2006, estimations of undiscovered offshore
resources in US: ~86 billion barrels of oil and ~420
trillion feet of gas.
• In 1998 worldwide, ~32% of oil and 24% of gas
production came from offshore wells.
• Major Offshore Oil Fields: Gulf of Mexico, Persian
Gulf, the North Sea, North Australia, Southern CA,
West Africa, Brazil and Vietnam
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• Annual world production of sand/gravel is ~1.2 billion
metric tons with a potential reserve of 800 billion metric
tons.
• United Kingdom and Japan: 20% of sand/gravel used
comes from the seafloor.
• US has reserves of ~450 billion tons of sand/gravel off
NE coast.
• Bahamas have ~100 billion metric tons of calcium
carbonate sands.
• In SW Pacific sands are mined for Fe, Pt, Sn, Au, U and
Diamonds
• Phosphorites off coasts of Florida, N. Carolina, CA,
Mexico, Peru, Japan and Australia. World reserves 10
estimated at ~50 billion tons.
Methane or Gas Hydrates
Energy Source, Seafloor Stability, Climate Change
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Sampling Methods
Figure 3.25a
Chain Basket, Basalts from ~8km near Tonga Tench
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• Phleger Gravity
Corer
Piston
Corer
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Figure 3.27e
Shelf Sediments
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Glacial
Maximum
17,000 years
B.P.
~17 kilometers
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Continental Slopes and Rises
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Deep Marine Sediments
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Tektite Strewnfields
Manganese Nodules
North central Pacific, 5157 meters
Lithogenous Deep Marine Sediments
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1000 microns = 1 mm
The North Downs Formation, upper Cretaceous,
mostly coccoliths with some quartz and clay
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Figure 3.21b
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Ice Rafted
Sediment
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Boulder to clay size
particles also eroded
and transported to
oceans via glacial ice
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Glacier termination in
circum-polar oceans
results in calving and
iceberg formation
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As ice (or icebergs)
melt, entrained material
is deposited on the
ocean floor
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• Make your own Marine Sediment Outline
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