-
Metamorphic rocks
- Pre-existing rocks (protoliths) or
- sediments (ig/meta/sed) that have been altered by high temperature and or
- pressure, fluids, chemical gases, etc
- -schist, rhyolite, diorite, andesite, gabbro, basalt periodotite
-
Foliation
characterized by texture (how parallel minerals are to each other) – aligned bands
Gneiss is foliated, marble is not
-
Igneous rocks
cooling liquid rock (lava- when on the surface, magma when inside the earth)
-
exstrusive volcanic rocks
plutonic volcanic rocks
- exstrusive
- volcanic rocks – formed on surface
- plutonic
- volcanic rocks – formed below the surface
- make up 90% of the volume of Earth’s crust
- make up 90% of
- the volume of Earth’s crust
- make up 90% of
- the volume of Earth’s crust
-
Classifying Igneous Rocks
- Igneous rocks tend to have interlocking, intergrowing mineral grains
- Size of crystals controlled by rate of cooling
- color is controlled by mineral content
- light = quartz and feldspar
- crystallizes cool @ low temperatures
- dark – pyroxines, magnatite
-
Aphaneritic
rapid cooling, fine grains
-
Phaneritic
slow cooling, coarse grains
-
Porphoritic
large grains enclosed in smooth rock
-
Metamorphosis
recrystallization of minerals while rock remains in solid state
-
Sedimentary Rocks
- formed by the consolidation of eroded materials from pre-existing rocks. This may be
- fragments cemented together or material precipitated from mineral rich water solution
-
Importance of Sedimentary Rocks
Contain information about the past, biota, environmental conditions, etc
|
|
