Unit 6 Flashcards
Where are the two main sediement archives located?
Germany & Japan
What do sediments become after being lithified?
Sedimentary rock
How is lithogenous sediment created?
pre-existing rock from land (continents/islands) from:
erosion
volcanic eruptions
blown dust
Where is the highest deposition of lithogenous sediment?
Continental margin
What are the 4 ways to transport lithogenous sediments? Give examples for each
- Water (Yellowstone or Mississippi River)
- Wind (Saharan Desert)
- Ice
- Gravity (landsildes)
What is ice-rafted debris?
A way of dispersing lithogenous sediment:
1. sediments are locked into (obv frozen into) glacier
2. as glacier melts, sediments are released on the seafloor
Where are some places to find lithogenous sediments?
- bays and lagoons
- deltas at river mouths
-along beach shorelines
-continental margin
What mineral is most concentrated in lithogenous deposits? how would you know where to find them?
quartz; deposit of quartz tends to match global wind patterns
Where is neritic sediment found?
continental shelves, close to shore, shallow waters
Coarse or fine grain: neritic sediments
Coarse
low or high energy to deposit: neritic sediments
HIGH
Give some examples of neritic sediments:
- beach deposits (quartz rich sand)
- relict sediments
- turbidite deposits
- glacial deposists
what are relict sediments?
A sediment lying on the continental shelf which was deposited by processes no longer active in the area where the sediment now occurs.
what are pelagic sediments?
deep water deposits, finer grain, slowly deposits (LESS energy), open sea deposit location
What are some examples of pelagic sediments?
- abyssal clay
- wind-blown dust
-volcanic ash
why is abyssal clay red
oxidized iron
What are biogenous sediments? what are the 2 major types & which is more abundant?
derived from the remains of hard parts of once-living organisms
- Macroscopic (shells, bones)
- Microscopic (tiny shells or tests) MORE ABUNDANT
What are tests?
the hard parts of microscopic organisms that make up biogenous sediment
What are 2 types of biogenic ooze & what are they made up of?
- siliceous (silica from diatoms and radiolarians
- calcaerous (organisms that contain calcium carbonate)
What is marine snow? Where does it land relative to where it is produced? How long does it take to land?
basically made from poop rockets of zooplankton
lands not far from production spot
10-15 days
What are diatoms? Where can you find them?
= microscopic algae whose tests produce silica (siliceous ooze)
- photosynthetic (only found in upper, sunlit surface waters)
How do diatoms move?f
they are free floating (planktonic) and drift with currents
What are radiolarians? What is their main food source?
single cell protozoans (animals) whose tests produce silica (siliceous ooze)
- rely on food from the environment
What is diatomaceous earth?
Lithified siliceous ooze that has many commercial uses
What two organisms generate the calcium carbonate needed to make up calcareous ooze?
Coccolithophores & Foraminifera
What are coccolithophores? Where are they commonly found?
micrscopic photosynthetic algae
blooms found in high latitude areas
What are foraminifera?
mostly planktonic (sometimes benthic) microscopic protozoans
Difference between Planktonic and Benthic
Planktonic organisms float freely with currents while benthic organisms live on the bottom of bodies of water/within seafloor sediment
What science are foraminifera useful for
paleoceanography (used to map what climate was like before)
What is a lysocline?
depth at which CaCO3 (calcium carbonate) begins to dissolve rapidly
What is the average lysocline?
4000m
What is the CCD?
Calcite compensation depth
What is the average CCD?
4500m
Where is CaCO3 saturated? Under-saturated?
Warm, shallow oceans; cool, deep oceans
Describe conditions below & above the CCD
Above CCD: calcite stable and not dissolved
Below CCD: different conditions cause calcite to dissolve
How is there calcareous ooze BELOW the CCD?
seafloor spreading (mid-ocean ridge)
waht are some factors that determine there are enough test/skeltons to consider ocean sediment biogenous?
- productivity
- dissolution/destruction
- dilution
what are hydrogenous sediments made from?
materials dissolved in the water
what is precipitation?
change from the dissolved to the solid state resulting from a change in conditions
name 5 different types of hydrogenous sediments
- manganese nodules
- phosphates
- carbonates
- metal sulfides
- evaporites
