2B.3 Flashcards
What does lithology mean?
refers to the physical characteristic of the rock.
What does lithology effect on what scale?
on a medium or meso scale
What is igneous rock?
The most resistant rock eg Granite
It is made up of interlocked crystals in a crystalline structure that are well connected impermeable and have few weaknesses
What do igneous rocks cause?
steep cliffs
0.1-0.3cm/year
Eg Lands End in Cornwall
What is metamorphic rock?
Well connected rocks that are impermeable but folded so create faults and joints as a weakness.
Eg marble, slate, schist
What do metamorphic rocks cause?
rocky coastline
steep profiles
erode slowly (0.5-1cm/year)
Eg St Ives in Cornwall, slate
What is sedimentary rock?
Layers of dead organisms compressed over millions of years in strata. eg Limestone and chalk.
What does sedimentary rock cause?
Steep cliffs and headlands and wave-cut platforms
They are vulnerable: clastic, in strata, porous and permeable (limestone 1-2cm/year) (chalk 1-100cm/year)
What are unconsolidated rock?
layers of permeable rock where water can remove the cement between particles from water pressure reducing stability
What do unconsolidated rock cause?
Rock falls and through falls,slumping, mudslides
eg Sandstone 10-100cm/year
Eg boulder clay on Holderness coast (NE) where 100-1000cm year
What can tectonic processes cause in rocks?
changing dip eg Lulworth cove
What are the type of cliff faces that cause recession?
Steep dips
Horizontal strata
towards the sea
away from the sea (landward)
What is differential erosion?
erosion that happens at varying rates due to geological structure of the rock
How can recession rates be determined?
examining historic maps and images over recent ones.
How has marram grass stabilised coastlines?
long roots - moisture
roots capture sand
example of xerophyte - lives in arid conditions
Waxy leaves prevent evaporation
