Marble Contact Or Regional Metamorphism

Marble is created from limestone that has been subjected to heat.

Marble contact or regional metamorphism.

The type and intensity of the metamorphism and width of the metamorphic aureole will depend on a number of factors including the type of country rock the. It is composed primarily of the mineral calcite caco 3 and usually contains other minerals such as clay minerals micas quartz pyrite iron oxides and graphite under the conditions of metamorphism the calcite in the limestone recrystallizes to form a rock that is. Some foliation may be present if the marble contains micas. Regional metamorphism causes a layered or platy structure in rocks called foliation.

The higher temperatures the pyrometamorphism effect as it is known whereby not just most but practically all the marble quarried is of fine commercial grade as i have found out and the new owners of the. Regional metamorphism by contrast takes place over large areas and is high grade metamorphism. The three types of metamorphism are contact regional and dynamic metamorphism. Burial metamorphism differs from regional and contact metamorphism in that it is the result of rocks being buried deeper into the earth s crust through tectonic movements.

Regional metamorphism is associated with the major events of earth dynamics and the vast majority of metamorphic rocks are so produced they are the rocks involved in the cyclic processes of erosion sedimentation burial metamorphism and mountain building events that are all related to major convective processes in earth s mantle. Contact metamorphism creates marble superior in every way to that of regional metamorphism by the very nature in which it was created. It s a perfect rock to use because it s soft the white mineral that dominates it is not quartz but calcite it can form either by regional metamorphism or contact metamorphism near igneous intrusions. Any type of magma body can lead to contact metamorphism from a thin dyke to a large stock.

Metamorphism can be instantaneous as in the shearing of rocks at plate boundaries or can take millions of years as in the slow cooling of magma buried deep under the surface of the earth. An example of contact metamorphism is the metamorphic rock marble. Regional pressure dominated metamorphism occurs over large areas during periods of mountain building. There are three ways that metamorphic rocks can form.

Eclogites usually do not show foliation. These are medium to coarse grained consisting mostly of garnet and green clinopyroxene called omphacite that result from high grade metamorphism of basic igneous rocks. Contact metamorphism is the name given to the changes that take place when magma is injected in the surrounding solid rock country rock.