The Rock Cycle • The rock cycle is a fundamental concept in geology that describes the dynamic transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous.
Igneous • Rocks are formed from cooled magma the slower they cool the larger the crystals are. They can be cooled underground and are called intrusive; if they are cooled above ground they are extrusive.
Metamorphic • A rock resulting from the change of preexisting rock as a result of the effect of heat , pressure, chemical action or combination of these.
Sedamentary A rock formed from precipitation from a solution , by accumulation of organic materials or by sedimentation and cementation of sediments derived from preexisting rocks and transported to a site of deposition by water , wind or ice. Types of Sedimentary rocks: Clastic : fragmented rock Crystalline,sedimentary rock that has interlocking crystals. Amorphous: very compact texture finely divided non crystalline material. oolitic: spheroid particles less than 2 millimeters called ooliths. bioclastic : This texture Is produced by aggregation of fragments of organic remains , the most common of which are shell fragments. .
Cooling • When liquid or hot magma/lava is reduced in temperature until it becomes solid.
Heating and Pressure • Heating: When a rock is heated and the temperature increases until it changes shape or becomes liquid magma. • Pressure: Pressure (the symbol: P) is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.
Lithification • The combination of processes that convert a sediment into sedimentary rock
Intrusive and Extrusive Igneous • Intrusive : magma that slowly cools underground forming crystals. • Extrusive: lava that cools rather quickly above the ground.