coastal recession and lithology

Question 1

igneous

Answer 1

granite, basalt
very slow erosion rate
crystalline, make strong resistant rock
few joints
limited weaknesses for erosion to exploit

Question 2

metamorphic

Answer 2

slate, marble
slow erosion rate
some are crystalline, if so there is foliation where the crystals are in one direction
which produces weaknesses
often folded and fractured

Question 3

sedimentary

Answer 3

shale, sandstone
fast erosion rate
clastic so erode quicker than crystalline
shale has bedding planes and fractures, higher weaknesses

Question 4

geological structures

Answer 4

bedding plane- layers of sedimentary rock, line between beds is a weakness
fault- fracture between rocks of displacement, occur due to stress (tectonic)
fold- rock is bent during tectonic, irregular occurance of rock at surface, diff rate of erosion

Question 5

how do sand dunes start

Answer 5

lsd deposits material in intertidal zone
tide ebbs, sand drys out, winds move material through saltation
plants colonise area, high ph level due to calcium carbonate from shells

Question 6

embryo dune

Answer 6

first to develop, stablised by lyme and marram grass, grass traps more sand, become increasingly arid
need succlenet leaves to store water ( sand couch)

Question 7

foredune

Answer 7

attain height of 5m, bcome grey as humus and bacteria from plants and animals is added
gradually become more acidic and vegetation covered