Sedimentary Rocks - L25-

Question 1

What does SSR stand for

Answer 1

Sedimentary stratigraphic record

Question 2

Thickness of sediments across the world

Answer 2

0.82-20km

Question 3

Problems with the SSR

x3

Answer 3

1) incomplete
2) Not always precise dates for the units studied
3) Not a continuous record

Question 4

Accommodation Space

Answer 4

The volumetric space within which sediment can accrue

Question 5

What does deposited sediment equal when the accommodation space is larger than the sediment supply?

Answer 5

Sediment supply

Question 6

What is deposited sediment equal to when the supply of sediment is larger than the accommodation space?

Answer 6

The accommodation space

Question 7

What sedimentary condition is found within the rock record

• so which rocks do we see

Answer 7

Depositional = aeolian and carbonate

Question 8

Which rocks do we not see in the sedimentary record?

Answer 8

Erosional - so glacial and alluvial

Question 9

What 3 things do we need to get ancient rocks for modern analysis

Answer 9

1) Accommodation space
2) Basins
3) Post-depositional Survival (as even now ancient but exposed sedimentary rocks are being eroded)

Question 10

What is accommodation space filling dictated by

Answer 10

base level

Question 11

What is base level

Answer 11

The level above which deposition is temporary and erosion occurs

Question 12

What is a diachronous facies

Answer 12

The same sediment deposited at different points at different times

Question 13

Walther’s Law

Answer 13

The transition between layers found in vertical-based deposits, where there is no break in succession, are the ones that are also found in laterally adjacent depositional environments

Question 14

Oldest Sedimentary rock in Britain

Answer 14

Mesoproterozoic

• Meall Dearg Formation - Scotland

Question 15

Why is it harder to rpedict the shape of the continents and tectonic plates after the Permian

Answer 15

Subduction zones have destroyed the continent or oceans - don’t know when continent became ocean plates etc

Question 16

Allogenic Processes

Answer 16

External to the system - climate and tectonics and leave sedimentary and geomorphic signatures

e.g Earthquakes, floods, waves, sea level

Question 17

Autogenic Processes

Answer 17

Pattern formation arises from how they were made - from growth

e.g Dune migration, River avulsion, Delta Growth

Question 18

Sadler Effect - 1981

Answer 18

The rate of sedimentation is more difficult to ascertain due to erosion

• the gaps skew the record of time and so understanding the parts missing is just as important