Physical Geology concepts.pdf
3 Rock Types
Igneous – Formed when molten rock (magma) cools.
-Extrusive (rock is ejected from the Earth’s surface and then cools)
-Intrusive (rock remains below the Earth’s surface, cooling slowly).
Sedimentary – Formed when sediment layers that accumulated at the
Earth’s surface are lithified (compacted and cemented) into a rock mass.
Metamorphic - New rocks formed from existing sedimentary or igneous
or metamorphic rocks that are subjected to heat and pressure.