09 Mar 09 Metamorphic rock
Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means “change in form”. The protolith is subjected to heat and pressure (temperatures greater than 150 to 200 °C and pressures of 1500 bars[1]) causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic rock. Metamorphic rocks make up a large part of the Earth’s crust and are classified by te... Full articleTags: metamorphic rock
09 Mar 09 Sedimentary rock
Sedimentary rock is one of the three main rock types (the others being igneous and metamorphic rock). Sedimentary rock is formed by deposition and consolidation of mineral and organic material and from precipitation of minerals from solution. The processes that form sedimentary rock occur at the surface of the Earth and within bodies of water. Rock formed from sediments covers 75-80% of the Earth’s land area, and includes common types such as limestone, chalk, dolostone, sandstone, conglomerate, some types... Full articleTags: sedimentary rock
09 Mar 09 Igneous rock
Igneous rock is one of the three main rock types (the others being sedimentary and metamorphic rock). Igneous rock is formed by magma (molten rock) being cooled and becoming solid . They may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. This magma can be derived from partial melts of pre-existing rocks in either the Earth’s mantle or crust. Typically, the melting is caused by one or more of three processes: an i... Full articleTags: Extrusive igneous rocks, Igneous rock, Intrusive igneous rocks
09 Mar 09 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. As the diagram to the right illustrates, each type of rock is altered or destroyed when it is forced out of its equilibrium conditions. An igneous rock such as basalt may break down and dissolve when exposed to the atmosphere, or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics... Full articleTags: Igneous rocks, metamorphic rock, rock cycle, sedimentary rock
09 Mar 09 Rock
In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids. The Earth’s outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic. The scientific study of rocks is called petrology, and petrology is an essential component of geology. Rocks are classified by mineral and chemical composition, by the texture of the constituent particles and by the processes that formed them. These indicators separate ro... Full articleTags: Igneous rocks, metamorphic rock, rock, sedimentary rock
