Submergent landforms Flashcards
What is a ria?
A submerged river valley, the flood plains/lowest parts are drowned but valley sides are exposed.
What does a rias cross-section look like?
Shallow water which is deeper towards the centre, sides are gently sloping.
What does a plan view of a ria look like?
widening following the route of the river valley, formed by fluvial erosion in channels and sub-aerial processes on valley sides.
Where can you find a ria?
Salcombe, Devon has a deep ria with a shallow threshold because of sand bar deposited in low e environment of Kingsbridge estuary.
What is a fjord?
A submerged glacial valley with steep valley sides and uniformly deep water, U shaped cross section. Consists of glacial rock basin with a shallow threshold.
When were these landforms formed?
In post-glacial sea level rise of the Flandrian Transgression, deep water meant high marine erosion.
Where can you find fjords?
Milford sound, New Zealand, fjords have been infilled with sed deposited by South Alp glaciers meltwater.
How do shingle beaches form?
More land ice causes sea level to fall and areas of ‘new’ land emerge which accumulate sed. End of glacial period, sea levels rise again, pushing sed onshore. Chesil beach formed this way during Flandrian T.
