Rocks Flashcards
How are sedimentary rocks formed?
They are formed when sediment such as sand and gravel settle at the bottom of a body of water like a river or sea. Then over time it gets compressed into rocks.
Give two examples of sedimentary rocks
Limestone and Sandstone
How are igneous rocks formed?
They are formed in volcanoes when magma is exposed to the air, causing it to cool.
Give two examples of igneous rocks?
Granite and Basalt
How are metamorphic rocks formed?
They are formed when sedimentary rocks are compressed under great pressure and heat.
Give two examples of metamorphic rocks?
Slate and Marble
How does the speed in which magma cools effect the rock type?
Magma that cools slowly forms large rock crystals such as granite (intrusive) and if it cools slowly, it forms small rock crystals such as basalt (extrusive).
What is striated rock?
Rock that has been scratched by ice (glacier) moving over it with sediment stuck to the bottom.
What is a cirque?
The bowl at the top of the valley caused by the movement of a glacier.
What is polished rock?
Rock that has been polished by a glacier passing over it with no sediment underneath it.
How does a batholith form?
Magma rises to the earth’s surface and cools to form igneous rocks e.g. granite. The rocks above it then erode away over time to leaving exposed igneous rock.
What are the economic uses of granite and basalt?
granite- kitchen worktops + gravestones
Basalt- roads and railways
How is a ribbon lake formed?
It is formed when a glacier erodes a patch of soft rock forming a basin that fills with water and becomes a ribbon lake.
What is trill/boulder clay?
Rock deposits laid down by a glacier.
What is an erratic?
A large rock found on its own and not in piles.
