Flashcards in Sea Level Change Deck (8)
How much lower was the sea level 18,000 years ago?
Which time period has since the greatest amount of sea level change?
Last 500 years risen by 10 meters
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
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
Where do coastlines of emergence occur?
Give some features
Where sea level has lowered,
Raised beaches along with relict landforms
Wave cut platforms
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
How fast are sea levels rising currently?
2mm per year