ROCK
By Robbie Stratakos
The Rock
The rock is composed of minerals, and they"re classified by how they were formed (origin). There are three types of rocks: Igneous, Sedimentary, and Metaphoric.
Igneous Rocks
Igneous Rocks are formed by cooling and crystallization of molten rock. They are formed inside and outside if a volcano. The two main types of Igneous rock are Intrusive and extrusive. Intrusive Igneous Rock is rock that crystallizes slowly inside the earth's crust, and Extrusive Igneous Rock is rock that crystallizes quickly at the earths surface.
Sedimentary Rocks
Sedimentary rocks are composed of the weathered remains of other rocks. They're usually formed by the compaction and cementing of sediments. The main types of sedimentary rocks are Clastic, Bioclastic and crystalline. Calstic is made of different sized particles cemented together. Bioclastic are formed by the accumulation of plant and animal remains. Crystalline are deposited chemicals in seawater precipated and fall to the ocean bottom.
Metamorphic Rocks
Metamorphic Rocks form when other rocks are exposed to heat and or pressure without melting. There is foliation which us an allignment of minerals in a Metamorphic rock. There is banding which is a type of foliation that's wavy colored stripes. There are two types of Metamorphic Rock: Regional and Contact. Regional Metamorphism is when large masses of rock are changed by deep burial deep within the earth. Contact Metamorphism is a chemical and physical change to a rock caused by nearby intrusion or extrusion of molten rock.
Gabbro
Gabbro is an Igneous Rock. Gabbro's texture is Coarse and it is non-vesicular. The crystals formed inbetween, and its density is very high. It is darker colored and its composition is Mafic. The amount of Plagioclase Felspar is fifty percent, the amount of Proxene is 40 percent, and the amount of Amphibole is ten percent.
Limestone
Limestone is a Sedimentary Rock. Limestone is a chemically organic formed Sedimentary Rock. Its texture is Crystalline or Bioclastic, and its grain size Microscopic to very coarse. Its composition is Calcite. Limestone also precipitates of biologic origin or cemented shell fragments.
Marble
Marble is a Metamorphic Rock. Its texture is nonfoliated, and its grain size is fine to coarse. It composition is calcite and or dolomite. It is also both a Regional and Contact type of Metamorphic Rock. It is also Metamorphism of Limestone and or Dolostone
The Rock Cycle
The Rock Cycle is a model showing how rocks and Sediments change over time.