Types of Rocks
What are the three main types of rocks?
Igneous, sedimentary, and metamorphic
What is the difference between intrusive and extrusive igneous rocks?
Intrusive rocks form underground with large crystals; extrusive rocks form on the surface with small crystals
What are sediments?
Small pieces of rock, mineral, or organic material
What does “metamorphic” mean in Greek?
To change form
What is the rock cycle?
A continuous process where rocks change from one type to another
Which type of rock forms from cooled magma or lava?
Igneous
What type of igneous rock is granite?
Intrusive
What process turns sediments into sedimentary rock?
Compaction and cementation
What causes a rock to become metamorphic?
Heat and pressure
Can a sedimentary rock become an igneous rock? How?
Yes; it melts into magma, then cools and hardens
Which type of rock is formed through heat and pressure?
Metamorphic
What type of igneous rock is basalt?
Extrusive
Name a common sedimentary rock formed from sand.
Sandstone
What is the difference between foliated and non-foliated metamorphic rocks?
Foliated rocks have layered or banded appearance; non-foliated do not
What role does heat play in the rock cycle?
It can melt rock into magma or cause metamorphism
Which type of rock is formed from compacted sediments?
Sedimentary
Why do intrusive igneous rocks have larger crystals?
They cool slowly, allowing crystals to grow larger
How do fossils form in sedimentary rocks?
Organisms get buried in layers of sediment and are preserved over time
Name a metamorphic rock that forms from limestone.
Marble
How can weathering affect a metamorphic rock?
It can break it down into sediments
What type of rock can form from any other rock type?
Metamorphic
What determines whether magma forms granite or basalt?
The rate of cooling and the location (underground or surface)
What are the three main types of sedimentary rocks?
Clastic, chemical, and organic
How does pressure deep underground affect rock structure?
It re-aligns minerals and can create foliation or denser structures
Describe a complete cycle where an igneous rock becomes sedimentary, then metamorphic.
Igneous rock weathers into sediment, compacts into sedimentary rock, then undergoes heat and pressure to become metamorphic