Rocks Flashcards
(29 cards)
What is the process of compaction called in sedimentary rocks
Lithification
What texture do intrusive rocks have
Extrusive?
Rough - large crystals
Smooth - small crystals
What is a batholith?
Dykes?
Sills?
Batholith-domes underground of cooled magma that gave formed domes of igneous rock
Dykes vertical gap of cooled magma
Sill- horizontal
Describe the distribution of rock types in the UK
Sedimentary is the south of the UK ie wales n England and Ireland
Metamorphic north-Scotland
Igneous-scattered around the north
When was chalk chalk clay Carboniferous limestone and granite
Chalk top of table
Clay Jurassic
Carboniferous limestone Carboniferous
Granite bottom of table
How are tors formed
Granite had lots of joints which aren’t evenly spreaf
Freeze thaw n chemical weathering wear down the parts with a lot of joints in faster
Sections with fewer joints weather more slowly so stick out at surface leaving tors
What are the characteristics of a granite landscape
Tors
Granite is impermeable so doesn’t let water through which creates Moorland-waterlogged and acidic soil with low growing vegetation
Contour lines are found close together on a map
Flat topped moorland
Why does horizontal layer of chalk and clay form
Sometimes tilted diagonally by earths movements
What is the steep slope of the escarpment called and gentle slopes called
What is a spring line
Why do chalk areas have dry valleys
Scarp slope- steep
Gentle slope-dip slope
Chalk is permeable so it can store water, water flows through the chalk and emerges where the chalk meets impermeable rock, this is called the spring line
The water is flowing underground so there is no stream or river flowing through them
What is a limestone pavement and how is it formed
Like stone has been exposed at the surface due to chemical erosion and mechanical erosion, the joints become widened to leave dips between the rock these are called Grikes , the blocks are allied clints
Malham cove
What are swallow holes
Example
Weathered holes in the surface
Gaping hill
How is a cavern formed in Carboniferous rock
River goes down swallow hole
Reaches lots of joints and bedding planes which causes more chemical weathering from the weak carbonic acid in the water. forming a cave
Caves gets bigger eg white scar caves
Turns into a cavern
How is a limestone gorge formed
Example ?
Cavern enlarges as the rainwater and rivers deep deep through joints and bedding planes (chemical weathering)
Cavern becomes higher thinner so has nothing to support it
Cavern roof collapsed creating a steep sided gorge
Eg Gordale scar
What are resurgent rivers
Rivers that pop out at the surface when the limestone meets and impermeable rock
Stalactites and stalagmites
What are they called when they meet?
What is a curtain
Water that seeps through joint n bedding planes contains minerals, when the water drops Ito a cavern the mineral solidify and built up over time
Pillar
When water flows Ina sheet a curtain builds up
what is granite used for?
Building stone for flooring n worktops
Opportunities for rearing livestock - not good for arable farming
Good place to build reservoirs as its impermeable
CASE STUDY DARTMOOR lots of granite quarries, eg? Quarried granite used for? Why do people visit Dartmoor? Farming? Reservoirs
Meldon quarry, granite used to build nelsons column
Millions of people visit Dartmoor every year to enjoy features of a granite landscape e.g. Bowermans nose and hound tor
290 000 hecteres of land used for rearing live stock (only 900 of arable)
8 reservoirs in Dartmoor some of which supply water to Plymouth
What is the appearance of sedimentary rocks
Metamorphic
Sedimentary- crumbly with a rough texture Contain fossils Metamorphic Shiny appearance Many layers within
What is land and economic uses of granite
Dartmoor prison- walls strong impossible to escape - in middle of nowhere
Headstones- last millions of years big crystals so pretty
Rip rap won’t be eroded by sea so good for protection
Reservoirs- impermeable
Sheep farming
Army training
What are the pros and cons of the London aquifer
Good - Make money Doesn't dry out after a drought Stores water for years Boreholes can be dug down to get water Clean n useful source of minerals 20% of London get their water form it Bad- Takes a long time for water to be replaced Has a limit to how much water it can hold as u can't make it any bigger
What are Grykes and clints
Grykes- pattern of englarged joints on limestone pavement
Clints - flat surfaces
An example of a limestone pavement is Malham cove
CASE STUDY SOUTH DOWNS
Clay vales- flat lush grass ideal for Cows
Dip slope- gentle gradient rough grazing for sheep
Scarp n dip slope
Escarpment
SOUTH DOWNS
What are the land and economic uses of clay and chalk?
Aquifer
Tourism
Building materials
Chalk provides short turf grass for sheep grazing
Clay provides long lush grass for dairy farming
CASE STUDY - Yorkshire dales
What are the land and economic uses of limestone areas
Limestone helps to fertilise acidic soil as it is a base so it neutralises it
Building material e.g. Houses of Parliament
Scenery above n below ground encourages tourism e.g. Yorkshire dales national park
Sheep farming
