Rocks Flashcards
Name 3 periods/epochs
Cretaceous Jurassic Triassic
What era was/is clay found in
Quaternary Teriatiary Jurassic Triassic Permian
What era was chalk found in?
Cretaceous
What era was limestone found in?
Carboniferous
What era was granite found in?
Pre-Cambrian Devonian
Where in the UK is clay found?
London basin
Where in the UK is chalk found?
Chiltern hills North downs South Downs
Where in the UK is limestone found?
Yorkshire dales
Where in the UK is granite found?
Dartmoor Lands end
Label the map showing which rock is found
How are igneous rocks formed?
Igneous rocks are formed by the solidification of molten material from below the earths surface. Extrusive igneous rocks are cooled quickly so small crystals form. Intrusive igneous rocks are cooled slowly so large crystals form .
Give an example of an intrusive and extrusive igneous rock
Extrusive - basalt Intrusive - granite
How are sedimentary rocks formed?
Sedimentary rocks are made from layers of sediment. They are grainy and crumbly and may contain fossil. The process that creates them is called sedimentation.
What are the 3 eras?
Caenozoic Mesozoic Palaeozoic
Give an example of a sedimentary rock
Limestone and chalk
How are metamorphic rocks formed?
Metamorphic rocks are formed by the effect of extreme pressures and temperatures deep within the earth. This alters the structures of the existing rock. They contain small crystals in layers. They are hard and smooth.
Give an example of metamorphic rock
Slate and marble
Where is the main areas in the UK where igneous rocks are found?
Scotland
Where is the main areas in the UK where sedimentary rocks are found?
North England
Where is the main areas in the UK where metamorphic rocks are found?
Wales
Define weathering
breakdown of materials in the earths crust into sediment in stitu.
define erosion
weathered rock is carried away by gravity, water, wind, and ice.
What do weathering and erosion do?
they work together to change the environment
How does freeze-thaw weathering work?
most rocks are hard, but despite this they can be broken by just a small amount of water getting into cracks in the rock. This is because as water freezes overnight it expands by 8 to 10% of its own volume. This creates powerful forces that can enlarge the cracks. This process is repeated and cracks start to spread through the rock. Eventually small pieces of rock called scree break off.
***what are a and b
a = joint
b = bedding plane
What is chemical weathering
CO2 dissolves into rainwater in the atmosphere to form a weak carbonic acid. This dissolves calcium carbonate (limestone) Limestone is particularly vulnerable due to the many lines of weakness (joints and bedding planes). This process happens over a long period of time.
What is onion skin weathering (physical)
rock is eroded layer by layer
what is biological weathering?
plant roots get into cracks in the rock and can physically open them further. Also decaying plant roots produce acid which can further weather the rock.
Describe the rock cycle
Lava spills out of the volcano and cools to form extrusive igneous rock. The weather breaks down the igneous rock by processes such as freeze-thaw. Erosion by rivers takes the sediments down to the sea. Sediments fall to the sea floor along with organic matter and are compacted to form sedimentary rock. Sedimentary rock is subducted into the mantle. It is heated and pressurised to form metamorphic rock.
Where is the granite case study?
Dartmoor