14. Marine Sedimentspages 113-136 in your text
It’s a Wet, Dirty World!
Ya Gotta Love It!!!
What is Sediment?
Matter that has been deposited by some natural process
Where does marine sediment come from?
Major Sediment Input to the Oceans-Land
Rivers contribute the mostOther Sources:
Glaciers and ice sheetsWind blown dustCoastal erosionVolcanic debrisGroundwater
How do we know? We sample!
How is marine sediment classified?
•Oceanic (AKA Pelagic) – those found in the open ocean (further away from land)
•Neritic – those found in waters above continental margins (closer to land) (coastal, “n” for nearshore)
What sediments are found where?
Neritic
Pelagic
What are the sediment types?
1) Terrigenous - derived from land2) Biogenous - derived from plants and animals3) Hydrogenous - formed on or in the
sediments on the sea floor (AKA Authigenic)4) Cosmogenous - particles from outer space
See page 119 in your text for a summary of these
1) Terrigenous Sedimentex. Sahara Dust –
Turbidites – another example of Terrigenous Sediment
Like a landslide, but it happens
under water
2)
If the ocean becomes more acidic, organisms with calcium skeletons will be
in trouble
Coccolithophore subjected to acidic seas – before and after:
Corals have calcium shells – imagine a
huge worldwide reef
die-off!
Can you find the coccolithophore bloom?
Still don’t believe a teeny organism can make sediment?
Famous White Chalk cliffs in Etretat France –
actually hundreds of millions of
coccolithophores!
Famous Painting by Monet:
3 & 4)
Evaporites – an example of (3) Hydrogenous Sediment
Form when seawater
evaporates and is not replaced with fresh
water
Sampling for an example of Hydrogenous Sediment –
Hydrothermal Vents
Closer to Home…
Long Island – Fire Island Beach Sand is mostly Quartz, Garnet, and Magnetite
Grain SizesWhat is the name of this equipment?
Need To Check Your Notes?• Check your details in your text and on
these sites:http://www.indiana.edu/~g131/seds.html
http://geology.uprm.edu/Morelock/dpseaterrig.htm
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