ocean sediments

Question 1

significance of ocean sediments

Answer 1

1. continents are sites of erosion, oceans are sites of deposition
2. oceans retain more complete record of history
3. law of superposition

Question 2

law of superposition

Answer 2

sedimentary layers deposited in time sequence , oldest on top

Question 3

name the 3 types of marine sediments

Answer 3

1. authigenic: formed in situ by precipitation of submarine alteration
2. terrigenous- detritus from continental erosion and explosive vulcanism
3. biogenic - shells or skeletons that sink ( silicate or carbonate)

Question 4

name the 4 origins of marinesediment

Answer 4

1. volcanogenic particles : from eruptions
2. lithogenous particles: weathering
3. glacially derived particles: rock beds from moving
4. biogenic particles: shells or skeletons from animals

Question 5

what controls the distribution of various kinds of seafloor sediments?

Answer 5

1. Delivery: no delivery- the wouldnt fucking be there
2. Dilution: too much sediment: high dilution rate, other sediment becomes unimportant
3. Destruction: certain processes destroy particles and remove them from seafloor sediment

Question 6

Authigenic Sediment Sources

Answer 6

1. Evaporites
2. phosphorites

Question 7

Terrigenous Sediment Sources

Answer 7

1. TO the continental margins
   - sediments funneled across margins though submarine canyons to deep sea fans
2. To the deep sea
   - volcanic ash, tephra- was transported by wind

Question 8

Biogenic Sediment sources

Answer 8

1. organisms use dissolved materials - they remove these to build shells and skeletons
   -carbonate and silica
   ** foraminifera, coccolithophorids, diatoms , radiolaria, pteropods

Question 9

what are siliceous sediments controlled by

Answer 9

delivery

Question 10

what are carbonate sediments controlled by

Answer 10

sediment depth, it will dissolve below CCD bc of acidity

Question 11

why is it important to understand CO2 in system

Answer 11

-builds organic matter
- controls ocean pH
-GHG effect
-affects calcium carbonate deposited on the sea floor

Question 12

what are the major dissolved forms of CO2

Answer 12

1. co2 (aqueous carbon dioxide)
2. HCO3- ( bicarbonate ion)
3. CO32- ( carbonate ion)

Question 13

explain calcium carbonate distribution

Answer 13

Ω= 1 is called the saturation horizon; , <1 undersaturated so net dissolution of caco3, =1 saturated so equilibrium, >1 supersaturated so net precipitation

• the upper icean is supersaturated
  -the saturation horizon is shallower in pacific

Question 14

factors affecting ccd

Answer 14

temp, depth, concentration of co2, pH, carbonate supply, terrigenous supply

Question 15

explain lysocline

Answer 15

where dissolution effects first appear in carbonate grains
- ccd is when deposition rate= dissolution rate