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Where do sediments come from?
space, eriosion, weather
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What are marine sediments
- eroded rock particles and fragments
- transported to ocean
- deposit by settling through water column
- oceanographers decipher earths history through studying sediments
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What the two types of weather
- Physical weather
- chemical weather
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weathering
breakdown of rocks, soils, and minerals through direct contact with the planet's atmosphere
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Some components of physical weathering
heat, water, ice, and pressure
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What is physical weathering?
- physical breakdown of rock
- makes small chunks and higher surface area
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some components of chemical weathering
soil pH, temperature, precipitation, composition of rock
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Trees help chemical weathering
H2O + CO2 -> Ca2+ + 2HCO3-
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What are the two types of chemical weathering?
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Congruent Chemical weathering
results in only dissolved ions
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Incongruent Chemical Weathering
results in newly made clay minerals and dissolved ions
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Example of congruent chemical weathering
- limestone weathering
- CaCO3 + H2O + CO2 -> Ca2+ +2HCO3-
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Example of Incongruent weathering
2NaAlSi3O8 + 11H2O + 2CO2 -> 2Na+ + 2HCO3- + 4H4SiO4 + Al2Si2O5(OH)4
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What is the size of particulate matter?
larger than .45 microns
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What is the size of dissolved matter?
below .45 microns
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How is marine sediment classified?
By origin
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What are the classifications of marine sediment?
- Terrigenous or ithgenous
- Biogenous
- Hydrogenous (aka Authigenic)
- Cosmogenous
- volcanogenous
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Cosmogenous Marine Sediment
- macroscopic meteor debris
- overall insignificant proportion of marine sediment
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Hydrogenous Marine Sediment
near hydrothermal vents, lots of metal ions are released intot he water and these ions oxidize or combine with silica and precipitate out as dark, metal rich sediment
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Volcanogenous marine sediment
- comes from volcanoes
- distributed in the marine realm by wind, streams, submarine gravity
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Terrigenous sedimetns
- most lithogenous sediments at continental margins
- coarser sediments closer to shore
- finer sediments farther from shore
- mainly mineral quartz
- erroded rock fragments from land
- agents of transport - water, wind, ice, gravity
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wind as an agent of transport
aolian
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Biogenous marine sediments
- hard remains of once-living organisms
- macroscopic
- microscopic
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Biogenic ooze
30% more or more tests
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Coccoliths
calcium carbonate
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calcium carbonate
coccoliths
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factors controlling distribution of biogenous sedimetns
- productivity
- destruction (dissolution)
- dilution
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