Search results
Results From The WOW.Com Content Network
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith ) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000 bar ) or more, causing profound physical or chemical changes.
In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment. Then, the rock was buried underneath subsequent rock and was subjected to high pressures and temperatures, causing the rock to recrystallize. The overall composition of a metasedimentary rock can be ...
Some of the most unusual concretion nuclei are World War II military shells, bombs, and shrapnel, which are found inside siderite concretions found in an English coastal salt marsh. [ 10 ] Depending on the environmental conditions present at the time of their formation, concretions can be created by either concentric or pervasive growth.
Depending on the structure, metamorphic rocks are divided into two general categories. Those that possess a texture are referred to as foliated ; the remainders are termed non-foliated. The name of the rock is then determined based on the types of minerals present.
Jadeitite – Metamorphic rock found in blueschist-grade metamorphic terranes Litchfieldite – Nepheline syenite gneiss; Marble – Type of metamorphic rock – a metamorphosed limestone; Migmatite – Mixture of metamorphic rock and igneous rock; Mylonite – Metamorphic rock – A metamorphic rock formed by shearing
Impactite is rock created or modified by one or more impacts of a meteorite. [1] [2] Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact. [3] On Earth, impactites consist primarily of modified terrestrial material, sometimes with pieces of the original meteorite. [3]
[33] [34] Subsequent erosion of the mountains exposes the roots of the orogenic belt as extensive outcrops of metamorphic rock, [35] characteristic of mountain chains. [33] Metamorphic rock formed in these settings tends to shown well-developed foliation. [33] Foliation develops when a rock is being shortened along one axis during metamorphism.
L-Tectonites are aligned in a linear fabric, which allows the rock to split into rod-like shapes due to the two intersecting planes. The foliation of this type is not strong. S-Tectonites are the fabric that is dominantly a foliation fabric which allows the rock to split into plate-like sheets that are parallel to foliation.