whats a rock?
A rock is the solid mineral material forming part of the surface of the earth and other similar planets, exposed on the surface or underlying the soil of the ocean
- Formed by cooling and cyrstallization of molten rock. (600-1000 degrees celsius)
- texture: non-vesicular ,vesicular, glassy, fine,coarse and very course.
- two main types are intrusive and extrusive. Intrusive rocks crystallize slowly inside the earths crust. Extrusive rocks on the other hand crystallize quickly at the earths surface.
- Most sedimentary rocks are composed primarily of the weathered (broken) remains of other rocks. They usually formed by the compaction (adding pressure) and cementing of sediments.
- texture: Clastic, crystalline, and/or bioclastic.
- They are commonly found at or near the earths surface.
- The two main types are clastic, Crystalline. Clastic are formed by different particles cemented together. Crystalline is deposited when chemicals in seawater- precipitates and fall to the ocean bottom evaporates.
- metamorphic rocks form when other rocks are exposed to heat and/or pressure without (melting-magma).
- Texture: Foliated, non-foliated, banding, mineral alignment.
- The two main types of rocks are foliation and banding. Foliation is the alignment of minerals in a metamorphic rock. Banding is casued by metamorphism.
- Texture: fine
- crystal size: less than 1mm.
- Color; darker
- Density: higher
- Composition: mafic
- Percentage of plagioclase feldspar:25%...proxene:65%...olivine:15%
- The rock is extrusive so in conclusion the rocks formed faster.
- chemically and/or organic
- Texture: crystalline
- Composition: Halite
- Comments: crystals form chemical precipitates and evaporates.
Grain size: Fine
Composition: various minerals
Type of metamorphism: regional
Comments: various rocks changed by heat from nearby magma/lava.
A model showing how rocks and sediments change over time.