Geological structure Flashcards
Geological structure
refers to the arrangement of rock units
Lithology
the type of rock
Geology
refers to the geological structure and lithology
rock strata
the different layers of rock in a location and how they relate to eachother
depending on their arrangement, the rate of erosion can be increased
for example if weaker rocks are exposed to erosion can be either layers of rock next to eachother or layers of rock on top of eachother
folds
bends in the rock
they are produced by sedimentary rock layers being squeezed by tectonic forces
main fold types
anticlines (arch shaped)
synclines (trough shaped)
dip
refers to the angle in which the angle at which the rock strata lie
(horizontally, vertically, dipping towards the sea or dipping in land)
sedimentary rocks and deposited horizontally but can be tilted by folding and failing it by tectonic plate movement
faulting
major fractures in the rock created by tectonic forces, with displacement of rocks either side of the fault line
they are often large scare, extending many km. it significantly increased the rate of erosion since zones of faulted rock are much more easily eroded
Joints
fractures in rocks (created without movement)
the occur in most rocks, often in regular patterns, dividing up rock strata up into blocks with regular shape
fissures
small cracks in rocks also represent weakness that erosion can exploit
can be caused by weathering eg freeze thaw/ animals and plants
Concordant coastline
Same type of rock along the length to the coast
Discordant
Alternating rock types along the coastline
Horizontal dip cliff profile
Stable coast
Near verticle profile
Wave cut notches (caused by hydraulic action)
Seaward dip high angle cliff profile
Unstable
High angle rock
Weathering and erosion at the bottom of cliff
Seaward dip low angle cliff profile
Low angle
Unstable
Weathering at the top of the cliff causes weakness, rocks fall off cliff and go into the sea
