Rocktizzlleee's
by Britany Rosa
What is a rock?
A rock is composed of minerals. They are classified by how they are formed (origin). There are 3 types of rocks,
Igneous Rocks
- igneous rocks are formed by cooling and crystallization of molten rocks
- they are formed in volcanoes
- the two type of igneous rocks are: intrusive and extrusive
- intrusive rocks are formed by crystallizing slowly inside the earths crust
- extrusive rocks are formed by crystallizing quickly at earths surface
Sedimentary Rocks
- sedimentary rocks are formed by compacting and cementing of sediments
- they are formed at or near earths surface
- the main type of sedimentary rocks are: inorganic land-derived sedimentary rocks such as clastic sedimentary rocks, chemically and/or organically such as bioclastic sedimentary rocks and crystalline sedimentary rocks.
- clastic sedimentary rocks are formed of different sized particles cemented together
- bioclastic sedimentary rocks are formed by the accumulation of plant and animal remains
- crystalline sedimentary rocks are deposited when chemical in seawater precipitate and fall to ocean bottom
Metamorphic Rocks
- metamorphic rocks are formed when other rocks are exposed to heat and/or pressure without melting (melting > magma > igneous rock)
- they are formed deep (up to 20 km) within earth
- the main types of metamorphic rocks are foliation and nonfoliation
- foliation is alignment of minerals in a metamorphic rock
- nonfoliation is no mineral alignment in banding
Igneous Rock: Rhyolite
- Rhyolite is an extrusive rock which means it was formed outside of a volcano and its crystals formed fast
- its texture is fine and its crystal size is less than 1 mm
- it is non vesicular
- its color is light, its density is low, and its composition is felsic (rich in Si, AI)
- Potassium Feldspar is 20%, Quarts is 40%, Plagioclase Feldspar is 20%, Biotite is 10%, and Amphibole is 10%
Sedimentary Rock: Conglomerate
- Conglomerate is an inorganic rock
- its texture is clastic and its grain size is as pebbles, cobbles, and/or boulders embedded in sand, slit, and/or clay
- its composition is mostly quartz, feldspar, and clay minerals; may contain fragments of other rocks and minerals
- rounded fragments
Metamorphic Rock: Quartzite
- the texture of quartzite is nonfoliated
- its grain size is fine to coarse
- its composition is quartz
- the type of metamorphism is regional or contact
- metamorphism of quartz sandstone
The Rock Cycle
Model showing how rocks and sediments change over time