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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.
A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term rock formation can also refer to specific sedimentary strata or other rock unit in stratigraphic and petrologic studies.
This page is intended to be a list of rock textural and morphological terms. A. Adcumulate; Agglomeritic; Adamantine a type of lustre; Amygdaloidal; Anhedral ...
Igneous rocks are divided into two main categories: Plutonic or intrusive rocks result when magma cools and crystallizes slowly within the Earth's crust. A common example of this type is granite. Volcanic or extrusive rocks result from magma reaching the surface either as lava or fragmental ejecta, forming minerals such as pumice or basalt. [5]
Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.
If the rock was originally banded or foliated (as, for example, a laminated sandstone or a foliated calc-schist) this character may not be obliterated, and a banded hornfels is the product. [42] Contact metamorphism close to the surface produces distinctive low-pressure metamorphic minerals, [ 30 ] such as spinel , andalusite, vesuvianite , or ...
The meteorite is the oldest known rock originating from Earth, being approximately 4 billion years old. Big Muley: Lunar Sample Laboratory Facility, Houston, Texas, United States: Anorthosite Moon rock collected by Apollo 16 astronauts. It is approximately 3.9 billion years old and is the largest Moon rock brought from the Moon. Black Rock
The change of rock composition most responsible for the creation of magma is the addition of water. Water lowers the solidus temperature of rocks at a given pressure. For example, at a depth of about 100 kilometres, peridotite begins to melt near 800 °C in the presence of excess water, but near or above about 1,500 °C in the absence of water ...