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The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
Folk's carbonate rock classification details the relative proportions of allochems in the rock and the type of matrix. The classification scheme covers most common carbonate rocks , however the more inclusive although less precise alternative, Dunham classification , may be preferred in some instances.
A facies encompasses all the characteristics of a rock including its chemical, physical, and biological features that distinguish it from adjacent rock. [ 2 ] The term "facies" was introduced by the Swiss geologist Amanz Gressly in 1838 and was part of his significant contribution to the foundations of modern stratigraphy , [ 3 ] which replaced ...
The use of rock has had a huge impact on the cultural and technological development of the human race. Rock has been used by humans and other hominids for at least 2.5 million years. [22] Lithic technology marks some of the oldest and continuously used technologies. The mining of rock for its metal content has been one of the most important ...
Gneiss, a foliated metamorphic rock. Quartzite, a non-foliated metamorphic rock. 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]
Sedimentary structures include all kinds of features in sediments and sedimentary rocks, formed at the time of deposition.. Sediments and sedimentary rocks are characterized by bedding, which occurs when layers of sediment, with different particle sizes are deposited on top of each other. [1]
In this series of zones, both pressure and temperature increase gradually along the metamorphic gradient. Barrovian metamorphism takes place during regional metamorphism, caused by crustal thickening in the roots of an orogenic belt (under mountain chains). Barrovian zones are especially easy to recognize in pelitic rocks.
Folds in the rock are formed about the stress field in which the rocks are located and the rheology, or method of response to stress, of the rock at the time at which the stress is applied. The rheology of the layers being folded determines characteristic features of the folds that are measured in the field.