Lesson 8 Flashcards
What are sub aerial processes?
Land based processes which alter the shape of the coastline. a mixture of mass movement and weathering
What is weathering?
decay and disintegration of rock
What is mass movement?
movement of weathered material down slope due to gravity
how does soil creep/solidification move?
flow imperceptible
How does mud flow/earth flow move?
flows slow to rapid
How does rock fall/rock slide/slumping move?
slides slow to rapid
What is the case study for landslides?
holbeck hall
How much land slided at Holbeck Hall?
55 meters
What caused the land slide at Holbeck Hall?
Rain fall and geology
What is the geology of Holbeck Hall?
Glacial till, soft rock (sandstone)
What is chemical weathering?
Rainwater is slightly acidic because carbon dioxide dissolves in it which reacts with minerals in rocks so rocks weather faster
What is acid rain?
rainfall made so acidic by atmospheric pollution that it causes environmental harm, buildings and rocks damaged
What is freeze thaw weathering?
Water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.
What is salt wedging?
Water enters cracks in rocks and when it evaporates it leaves salt behind, overtime salt builds up creating pressure which can cause rock to split
What is biological weathering?
Animals wear away rocks by burrowing into cracks making them bigger and plant roots do the same.
What is soil creep?
The slowest form of mass movement but almost continuous. Individual particles of soil move down hill
What are terracettes?
A ridge on the side of a hill formed when saturated soil particles expand, as they dry it causes them to move down hill slowly.
What is solifluction?
The gradual movement of wet soil or other material down a slope
When does solifuction happen?
happens during the summer thaw when the water in the soil is trapped there by frozen permafrost beneath it.
What are mud/earth flows?
Heavy rain causes a reduction in friction, thus the earth turns into mud and flows slowly over bedrock
What is rock fall?
Occurs when freeze thaw breaks large chucks away
The cliff has to be at an angle of 40 degrees
Material that breaks off is called scree and bounces down to the bottom of the cliff
What is rock/debris slides?
Rocks that are joined or have bedding planes parallel to the slope are susceptible to landslides.
An increase in water can reduce friction making it easier
Slabs of rock which slide over the underlying rock are called slip or plane
What is slumping?
Occurs in saturated conditions and steep slopes
Causes rotational scars
Material moves way in chunks
