How rock types influence recession - 2b.3

Cards (17)

what is geology 
the type of rock
what are the 4 types of rock
unconsolidated, sedimentary, igneous, metamorphic
what is unconsolidated rock 
sediment that hasn't been compacted and cemented (lithified)
example of unconsolidated rock
boulder clay - glacial till
which coastline is mainly composed of unconsolidated rock and what is the recession rate
holderness, 2-10m per year
what is sedimentary rock 
sediment that has been compacted and cemented (clastic or non clastic rock)
why is sedimentary rock not very resistant 
-weak bedding planes
-many joints due to compaction and pressure release
-clastic not crystalline
examples of sedimentary rock 
sandstone (clastic) and limestone (non clastic)
recession rate of limestone
1cm per year
what is metamorphic rock 
recrystallisation of sedimentary and igneous rock due to heat and pressure in earths core
why is metamorphic rock less resistant than igneous 
-the crystals often oriented in the same direction (foliation)
-many joints due to high pressure
what is foliation 
when the crystals are oriented in the same direction
what is igneous rock 
solidified magma/lava
why is igneous rock so strong
interlocking crystals
despite a few faults from cooling, less faults and joints
example igneous rock 
granite
recession rate of igneous rock
less than 0.1 cm per year
recession rate of metamorphic rock
01-0.3 cm per year