over the last 100 million years earth has been cooling down.
Antarctica's ice began forming 34 million years ago
define quaternary glaciation
alternating between glacial and interglacial periods over the last 2.6 million years.
we are currently in an interglacial period
define the greenhouse effect
solar radiation enters the earth's atmosphere and gases trap heat before it reflects into space
define the continental drift theory
continents split from one supercontinent called Pangea over the last 200 million years
define global atmospheric circulation
different types of environments at different latitudes:
Tundra at 90 degrees = cold and dry
temperate forests at 60 degrees = cool and humid
hot deserts at 30 degrees = hot and dry
tropical rainforests at 0 degrees = hot and humid
define eustatic sea level changes
changes in volume of water = global effect
causes of eustatic sea level change
change in mass of glacial ice = water trapped
thermalexpansion of water = water heated so more space between molecules
sea floor changes by tectonic processes
define isostatic sea level changes
elevation of land relative to sea level = local effect
causes of isostatic sea level changes
geological or tectonic processes such as uplift of land masses
downward pressure of ice mass lifting and letting land rebound = land uplift = rises above sea level = sea level drops
define emergent landforms
influenced by falling sea levels due to cooling climate = previously formed landforms will be inland and away from marine influence.
raisedbeaches, marineterraces, abandonedcliffs = beaches, shore platforms, coastal cliffs that are no longer interacting with wave energy
in the UK = most emergent coastlines due to eustatic sea level change because we have no tectonic boundary
define submergent landforms
influenced by rising sea levels due to warming climate = sea level is rising faster than land.
ria, fjord, shingle beach = landforms
the FlandrianTransgression = transition into current interglacial period = creating submergence landforms
define the Flandrian Transgression
around 12000 years ago (beginning of Holocene) = large number of glaciers retreated in the last phase of the glacial period = transitioning to interglacial
outline rias - submergent landforms
a drownedrivervalley
fluvial processes and rivers cut a channel to the new coastline
during the FlandrianTransgression = lower parts of valley is drowned and exposed to marine processes
outline fjords - submergent landforms
a drownedglacial valley
glaciers have more erosive power = steep cliff-like valley sides and deep water (often over 1000 m)
high energy environment = either deepened or infilled by sediment from continued erosion
area like New Zealand, glaciers melt and deposits sediment into fjords.
outline shingle beach - submergent landforms
rivers and glaciers deposit sediment in nearshore areas