Rocks Flashcards
What is the difference between intrusive and extrusive igneous rock?
Intrusive – magma cools inside the Earth’s crust
Extrusive – magma cools outside earths crust
How are igneous rocks formed?
Formed by magma in the molten interior of the earth
When magma erupts it cools to form volcanic landforms
What are some types of igneous rocks?
Pumice – polish, dental abrasive
Basalt – floor tiles, asphalt
Granites – countertops
Where are igneous rocks found?
On surface in areas of current or past volcanic activity
Deep underground almost everywhere
Basalt: giants causeway
Granite: Cornwall
How are sedimentary rocks formed?
Formed from sediments that have settled at the bottom of the lake, sea or ocean
Sediments came from eroded rock and skeletons of sea creatures
Sediments are compressed by successive layers and water to form rocks
What characteristics do sedimentary rocks have?
There are many strata, joints and bedding planes and faults
Soft rock, easily eroded
What are joints?
Vertical weaknesses within the layers of rock
What is a fault?
Birth movements have broken up the bed of rock
What are bedding planes?
Surface separating distinctive layers of sedimentary rock
Indicate the end of phase of deposition and the beginning of another
What are the different types of sedimentary rock
Compressed stone : sandstone – glassware
Compressed mud : Clay – bricks, pottery
Compressed animals and calcium : Limestone and chalk (carboniferous period) – Buildings
Where are sedimentary rocks found?
Riverbanks, cliffs
Line the majority of the ocean floor
Chalk: white cliffs of dover
How are metamorphic rocks formed?
Subjected to enormous heat or pressure deep within the earth near plate boundaries
Causes them to change into another rock type
What are the characteristics of metamorphic rocks?
Resistance to weathering and erosion
Hard wearing
What are the different types of metamorphic rock?
Limestone into marble – countertops
Shale into slate – roofing material
Where are metamorphic rocks found?
Deep underground, at base of mountains
Glaciated terrain
Surface of eroded mountains
Marble: italy
