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A Level Physical Geography > Sea Level Change > Flashcards

Flashcards in Sea Level Change Deck (8)
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1

How much lower was the sea level 18,000 years ago?

110meters

2

Which time period has since the greatest amount of sea level change?

Last 500 years risen by 10 meters

3

What is eustatic change? What are its causes?

Ocean level rises reative to the land
1) thermal expansion
2) melting of ice sheets
3) tectonic activity - displacement of water by moving the ocean basin up

4

What is isostatic change?

Level of land changes relative to the sea
1) tectonic activity - fold mountains
2) glaciation - heavy glaciers push the ground into the upper layer of the mantle, upon melting the land rebounds out of the asthenosphere
3) subsidence - ground water abstraction causes collapses

5

Where do coastlines of emergence occur?
Give some features

Where sea level has lowered,
Raised beaches along with relict landforms
Wave cut platforms

6

What are coastlines of submergence ?
What landforms occur?

Coastlines that have seen severe sea level rises
Rias - flooded river valleys with gentle profiles
Fjords - flooded glacial valleys with steep sides
Dalmatian coasts - concordant geology has valleys parallel to the coast which are flooded

7

How fast are sea levels rising currently?

2mm per year

8

Give four impacts that sea level rise has on coasts.

Increased storm frequency due to altered wind patterns etc
More costal flooding = lost agricultural land 0.3 meter rise = 8000Km2 in Bangladesh
Contamination of fresh water sources reduces biodiversity
Faster costal erosion rates