Metamorphic rock, any rock that results from the alteration of preexisting rocks in response to changing conditions, such as variations in temperature, pressure, and mechanical stress, and the addition or subtraction of chemical components. The preexisti
Examples of nonfoliated rocks include: hornfels, marble, novaculite, quartzite, and skarn. Photographs and brief descriptions of some common types of metamorphic rocks are shown on this page.Gneiss is a foliated metamorphic rock that has a banded appearance and is made up of granular mineral ...
Schist is a metamorphic rock that comes in almost infinite variety, but its main characteristic is hinted at in its name:Schistcomes from the ancient Greek for "split," through Latin and French. It is formed by dynamic metamorphism at high temperatures and high pressures that aligns the grains...
In most cases, rocks that are metamorphosed are heated and squeezed and pushed around, i.e. deformed. For instance, as an igneous pluton intrudes into the surrounding rock, it heats the rock and it also has to make space for itself and hence it shoulders aside the pre-existing rock. Thi...
(seeMETAMORPHISM). Metamorphic facies are usually classified according to the names of the main types of basic rocks that are stable in each facies (see Figure 1). Examples include the greenschist and glaucophane schist facies (low temperature, intermediate and high pressures), epidote-amphibolite...
Very simple: metabasalts react sensitively todifferent pressures and temperatures and also form rock types that are easy to distinguishmacroscopically—such as greenschist, blueschist, amphibolite, and eclogite.So all metamorphic rocks can be described with the corresponding facies concept and theprefix ...
The rock cycle: How different types of rock are formed The Earth's surface and crust are constantly evolving through a process called the... Video: Encyclopædia Britannica, Inc. Images gneiss Gneiss displays a well-developed foliation and a poorly developed schistosity and... ...
M.E. Jones, Mineralogical Magazine Contents: Metamorphic Fieldwork and Mapping -- Names and Categories of Metamorphic Rocks and Rock Units -- Rock Banding -- Minerals -- Compositions -- Grade -- Textures -- Fabric Types -- Relations to Structures -- Undeformed Pods -- Augen -- Pseudomorphs...
Seeing gneiss, gabbro, labradorite, diorite, and other types of rock marketed as "granite" disturbs many geologists. However, this long-time practice of the dimension stone trade simplifies discussions with customers since not everyone knows the technical names of unusual igneous and metamorphic rocks...
Hence, the combined petrological study on the eclogites and their surrounding metapelites is useful in revealing the metamorphic history of both rock types, which can demonstrate whether the peak conditions of the host rocks are consistent with the peak conditions of eclogites or not. In this ...