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The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks.
Primitive rocks are common on the surfaces of many asteroids, and the majority of meteorites are primitive rocks." [1]: 145 Widmanstätten pattern in an iron-rich meteorite. An example of a primitive rock is the achondritic iron-nickel octahedrite mineral seen in the Widmanstätten pattern that is found in a number of iron-rich meteorites.
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these ...
Rock art found in southeastern Venezuela may have come from a previously unknown culture. ... the research team discovered 20 rock art sites that show how the area was possibly used by indigenous ...
Serpentinization is a form of low-temperature (0 to ~600 °C) [5] metamorphism of ferromagnesian minerals in mafic and ultramafic rocks, such as dunite, harzburgite, or lherzolite. These are rocks low in silica and composed mostly of olivine ((Mg 2+, Fe 2+) 2 SiO 4), pyroxene (XY(Si,Al) 2 O 6), and chromite (approximately FeCr 2 O 4).
The classification method depends on the type and detail of research being conducted. [1] [2] [5] A sedimentary rock composed largely of gravel is first named according to the roundness of the gravel. If the gravel clasts that comprise it are largely well-rounded to subrounded, it is a conglomerate.
Many of the world's most valuable reserves of lead, zinc and silver, are found in rocks from this time, as well as rich sources of beryllium, boron and uranium minerals. [ 15 ] : 181 This interval also saw the formation of the supercontinent Columbia , its breakup, and the formation of Rodinia .
Anthropic rock is rock that is made, modified and moved by humans. Concrete is the most widely known example of this. [ 1 ] The new category has been proposed to recognise that human-made rocks are likely to last for long periods of Earth's future geological time , and will be important in humanity's long-term future.