marine sediment Flashcards
1
Q
what are the main types of sediment?
A
- terrigenous
- biogenic oozes
- authigenic
2
Q
what are terrigenous sediments?
A
- land derived
- continental sediments
- abyssal
- pelagic
- red clays
3
Q
what are biogenic oozes?
A
- biological material
- calcareous ooze
- siliceous ooze
4
Q
what are authigenic ooze?
A
- created in situ
- manganese nodules
5
Q
what is the indus delta?
A
- much depleted as a result of dam construction up stream
6
Q
what controls accumulation of ocean sediments?
A
- deposition rate from surface
- degree of preservation
7
Q
describe deposition rate from surface:
A
- for terrigenous sediments in the open ocean this is constant
- for biogenic sediments - depends on productivity in surface waters which in turn is linked to nutrient availability
8
Q
describe degree of preservation
A
- mineral sediments have very long lifespan
- some dissolve depends on conditions = depth, pressure, water, temperature
9
Q
what are calcareous materials?
A
- warm, shallow water saturated with calcium carbonate
- cool, deep ocean unsaturated with calcium carbonate
10
Q
what is the lysocline
A
- depth at which CaCO3 begins to dissolve rapidly
11
Q
what is the calcium compensation depth CCD?
A
- depth where CaCO3 readily dissolves
12
Q
what are authigenic processes?
A
- occurs after deposition
- can include precipitation of metals onto particles, precipitation of salts, or calcium carbonate in some conditions or simply formation of compounds such as rust
13
Q
what does authigenic mean?
A
- self originating
14
Q
what is the typical sediment structure
A
- oxygenated surface layer
- anoxic layer
- old chemically and physically stable sediment
15
Q
in voltaic cell, what happens at the anode?
A
- zinc will be dissolved from the electrode into solution
