Search results
Results from the WOW.Com Content Network
Foliation in geology refers to repetitive layering in metamorphic rocks. [1] Each layer can be as thin as a sheet of paper, or over a meter in thickness. [ 1 ] The word comes from the Latin folium , meaning "leaf", and refers to the sheet-like planar structure. [ 1 ]
Geologists define schist as medium-grained metamorphic rock that shows well-developed schistosity. [3] Schistosity is a thin layering of the rock produced by metamorphism (a foliation) that permits the rock to easily be split into flakes or slabs less than 5 to 10 millimeters (0.2 to 0.4 in) thick.
Cleavage is a type of secondary foliation associated with fine grained rocks. For coarser grained rocks, schistosity is used to describe secondary foliation. There are a variety of definitions for cleavage, which may cause confusion and debate. The terminology used in this article is based largely on Passchier and Trouw (2005).
Greenschists also have pronounced schistosity. [3] Schistosity is a thin layering of the rock produced by metamorphism (a foliation) that permits the rock to easily be split into flakes or slabs less than 5 to 10 millimeters (0.2 to 0.4 in) thick. This arises from the presence of chlorite or other platy minerals that become aligned in layers ...
Gneisses, which are more coarse grained and show thicker foliation than schists, with layers over 5mm thick. [23] These show less well-developed schistosity. [24] Granofels, which show no obvious foliation [23] or schistosity. [24] A hornfels is a granofels that is known to result from contact metamorphism.
A discontinuity can be, for example, a bedding, schistosity, foliation, joint, cleavage, fracture, fissure, crack, or fault plane. A division is made between mechanical and integral discontinuities. Discontinuities may occur multiple times with broadly the same mechanical characteristics in a discontinuity set, or may be a single discontinuity.
A massive metamorphic rock lacking schistosity or foliation. felsic Silicate minerals, magmas, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Light minerals (quartz and feldspar) greater than 60% - acid. [Granite (Rhyolite), Adamellite (Rhyo-dacite), Granodiorite (Dacite)].
Tectonites are rocks with minerals that have been affected by natural forces of the earth, which allowed their orientations to change. This usually includes recrystallization of minerals, and the foliation formation. Tectonites are studied through structural analysis and allows for the determination of two things: [2]