2B.3A: Lithology and Rate of Coastal Recession.
Bedrock lithology (igneous, sedimentary, metamorphic) and unconsolidated material geology are important in understanding rates of coastal recession.
How Lithology Affects Resistance:
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First, some rather important definitions:
Rate of recession is influenced by bedrock lithology (igneous, sedimentary or metamorphic) and the geology unconsolidated sediment.
Igneous
Metamorphic
Sedimentary
They are less resistant than metamorphic or igneous rocks, due to:
However, the rate of erosion varies from slow (0.5 cm) to fast (10 cm):
This is because:
Unconsolidated Sediment - sediment that has not yet been cemented to form solid rock (lithification) Drift geology is recently deposited unconsolidated sediment that usually overlies the solid geology of the bedrock. Some examples of unconsolidated sediment are: (or sand)
They are very easily eroded, resulting in very fast rates of recession
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