Rocks, Resources And Scenery Flashcards
How is igneous rock formed?
All igneous rocks are formed when molten rock (magma) from the mantle cools down and hardens.
What’s intrusive igneous rock?
Forms when magma cools down BELOW the earths surface. The magma cools very slowly, forming large crystals that gives the rocks a coarse texture.
Name the three types of rock:
Igneous , sedimentary , metamorphic.
What’s extrusive igneous rock?
These form when magma cools down after its erupted from the volcano onto the earths surface, the magma cools very quickly, forming small crystals that give the rocks a fine texture.
What’s sedimentary rock?
They’re formed when layers of sediment are compacted together until it forms a rock e.g chalk is made from layers of tiny shells and skeletons of sea creatures … And clay is made from mud and clay minerals compacted together
What is the process of compaction called?
Lithification
What is metamorphic rock?
They’re formed when other rocks (igneous, sedimentary or older metamorphic rocks) are changed by heat and pressure.
What ways can rocks be affected by heat and pressure to become metamorphic?
Rocks deep in the earth can be changed by pressure from the weight above them, tectonic plates collide and rocks change from the massive heat and pressure that builds up. Magma also heats the rocks in the crust causing them to change.
Name the 5 ways one rock can change into another:
Weathering/erosion, compaction, heat and pressure, cooling , melting.
What is weathering and what are the three types?
Weathering is the breakdown of rocks, the three types are mechanical, chemical and biological.
What is freeze-thaw weathering?
It’s a type of mechanical weathering where water fills cracks in rocks and expands when it freezes, making the crack bigger. It then thaws and repeats the cycle until the rock splits.
What is exfoliation weathering?
A type of mechanical weathering. In places where there’s a big daily temperature range (e.g deserts are hot during day and cold at night) surface layers of rock heat up and expand faster than inner layers and cool down and contract faster, causing pressure and the surface layers to peel off.
What is mechanical weathering?
The breakdown of rocks without changing their chemical composition and the material created doesn’t get taken away like with erosion.
