History of the Late Cenozoic

Question 1

What was the main orogenic process in the Late Cenozoic?

Answer 1

Mountain building of the Himalayas and Alps

Question 2

What can be used to work out the past effect of sea ice volume effect?

Answer 2

Magnesium calcium ratio
More temp more Mg thus affected sea oxygen isotopes

Question 3

What would the effect of all of the greenland land ice melting?

Answer 3

Sea level would be hundreds of meters higher diluting salinity losing the gulf stream

Question 4

What stability problem is experienced by Antarctica?

Answer 4

The east side is very stable being wholly on land but the western side is surrounded by water and more dynamic

Question 5

What would the effect of the whole of the western Antarctic ice sheet melting?

Answer 5

York and cambridge would become coastal town

Question 6

What is the history of the west Antarctic ice sheet?

Answer 6

It has been prone to collapse in warm periods (sensitive to CO2 climate warming)

Question 7

What produced CO2 in the Eocene?

Answer 7

India - Asia collision with resulting metamorphism and volcanics

Question 8

What happens to the carbon cycle when the Tibetan plateau formed?

Answer 8

Increased weathering (Frost shatter), reducing the atmospheric C reservoir

Question 9

What does global mean rate of chemical weathering depend upon?

Answer 9

Availability of fresh rocks and mineral surfaces brought about by fast tectonic uplift

Question 10

What did increased weathering brought about by the Tibetan plateau ~55Ma do to earths climate?

Answer 10

cools global climate and starts transition to icehouse earth

Question 11

What is evidence of the start of glaciers in the alps and the Mediterranean?

Answer 11

Massive increase of sediment flux

Question 12

What is the Uk stratigraphy controlled by?

Answer 12

Tectonic subsidence and uplift
Global sea level changes

Question 13

What was the transition of the Uk stratigraphy?

Answer 13

From sedimentary basins to regional uplift and compression

Question 14

What caused compression and uplift in the UK?

Answer 14

Upward movement and collision of the alps and Mid-Atlantic ridge spreading

Question 15

What was early Palaeogene deposition in the uk dominated by?

Answer 15

Shallow marine basins of the south of England especially the London and Hampshire basins

Question 16

What was occurring in the Midlands in the early Palaeogene uk?

Answer 16

It was being eroded by the North Atlantic igneous province

Question 17

What is the determining factor of deposition of the London basin?

Answer 17

By temperature and its relationship with sea levels

Question 18

Where is one of the best examples of the Hampshire basin?

Answer 18

Alum Bay on the isle of wight - with the Bracklesham formation

Question 19

What is the orientation of the Alum bay Bracklesham formation?

Answer 19

Near vertical hinting at tectonic rotation/ tipping

Question 20

What dies the reading formation consist of?

Answer 20

Consists of clays and marls mottled with reddish iron oxide stain - palaeosols

Question 21

What was the Reading formation originally?

Answer 21

grey soils deposited on a flood plain

Question 22

What type of folding is present in Alum bay?

Answer 22

Monocline

Question 23

What occurs towards the base of the Reading formation in Alum bay?

Answer 23

Thin conglomerate as a result of an unconformity

Question 24

What type of landscape can be seen on the top of the chalk in Alum bay?

Answer 24

It has been eroded unevenly due to presence of limestone creating castic landscape

Question 25

What is the London clay made up of?

Answer 25

Mix of unconsolidated mudstone with coarser sand and silt beds

Question 26

How is the London clay controlled by transgressive-regressive cycles?

Answer 26

Clay deposition in deeper water during transgression
Deposition of sands and silts in shallower waters during regression

Question 27

What was the environment like at the time of the London clay?

Answer 27

Sub-tropical seen by presence of turtle and alligator fossils ad palms in the midlands

Question 28

What would sea temp have been around the time of the London clay?

Answer 28

Around 30* (Known due to research by Tom Dunkley in Ireland which showed se temp was 27)

Question 29

What was the importance and complication of the London clays importance?

Answer 29

Was used for underground and cross rail but it is very unstable when exposed to water creating a concrete acid

Question 30

What is the poole formation?

Answer 30

lower part of the Bracklesham Group, non-marine deltaic facie

Question 31

What are the characteristics of the poole formation?

Answer 31

consists of sands, grey clays with plant debris & lignite beds and pipe clay (ball clay) beds

Question 32

What is the barton clay?

Answer 32

Grey clay with white aragonitic shells
Related to very shallow marine shoreline deposits

Question 33

What clasts can be seen in the Barton clay and what does it indicate?

Answer 33

Limestone casts which should be many units/ time below but must have been uplifted and eroded to be worked into the formation

Question 34

What caused the end of the S.England Palaeogene depostion?

Answer 34

Evidence of regression in the Bouldnor and Bembridge formations

Question 35

How old has the loch neigh depresseion been dated to?

Answer 35

By drilling sediments around the exterior is shows an age of 10 million years