Enclave (geology)

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In geology, an enclave is an aggregate of minerals or rock observed inside a larger rock body. Usually it refers to such situations in plutonic rocks. Micro-granular enclaves in felsic plutons result from the introduction of mafic magma into the magma chamber and its subsequent cooling following incomplete mixing. [1]

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<span class="mw-page-title-main">Granite</span> Type of igneous rock

Granite is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground. It is common in the continental crust of Earth, where it is found in igneous intrusions. These range in size from dikes only a few centimeters across to batholiths exposed over hundreds of square kilometers.

<span class="mw-page-title-main">Magma</span> Hot semifluid material found beneath the surface of Earth

Magma is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles.

<span class="mw-page-title-main">Rhyolite</span> Igneous, volcanic rock, of felsic (silica-rich) composition

Rhyolite is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent to granite.

<span class="mw-page-title-main">Volcanism</span> Eruption of molten rock onto Earths surface

Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a vent. It includes all phenomena resulting from and causing magma within the crust or mantle of the body, to rise through the crust and form volcanic rocks on the surface. Magmas that reach the surface and solidify form extrusive landforms.

<span class="mw-page-title-main">Magma (band)</span> French progressive rock band

Magma is a French progressive rock band founded in Paris in 1969 by self-taught drummer Christian Vander, who claimed as his inspiration a "vision of humanity's spiritual and ecological future" that profoundly disturbed him. In the course of their first album, the band tells the story of a group of people fleeing a doomed Earth to settle on the planet Kobaïa. Later, conflict arises when the Kobaïans—descendants of the original colonists—encounter other Earth refugees. The style of progressive rock that Vander developed with Magma is termed "Zeuhl", and has been applied to other bands in France operating in the same period, and to some recent Japanese bands.

<span class="mw-page-title-main">Rock (geology)</span> Naturally occurring mineral aggregate

In geology, rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere. 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.

<span class="mw-page-title-main">Dacite</span> Volcanic rock intermediate in composition between andesite and rhyolite

Dacite is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.

<span class="mw-page-title-main">Andesite</span> Type of volcanic rock

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<span class="mw-page-title-main">Magma chamber</span> Accumulation of molten rock within the Earths crust

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<span class="mw-page-title-main">Dike (geology)</span> A sheet of rock that is formed in a fracture of a pre-existing rock body

In geology, a dike or dyke is a sheet of rock that is formed in a fracture of a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.

<span class="mw-page-title-main">Flood basalt</span> Very large volume eruption of basalt lava

A flood basalt is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reaching the surface of the earth via a mantle plume. Flood basalt provinces such as the Deccan Traps of India are often called traps, after the Swedish word trappa, due to the characteristic stairstep geomorphology of many associated landscapes.

<span class="mw-page-title-main">Nevado de Longaví</span> Volcano in Chile

Nevado de Longaví is a volcano in the Andes of central Chile. The 3,242 m (10,636 ft) high volcano lies in the Linares Province, which is part of the Maule Region. It features a summit crater and several parasitic vents. The volcano is constructed principally from lava flows. Two collapses of the edifice have carved collapse scars into the volcano, one on the eastern slope known as Lomas Limpias and another on the southwestern slope known as Los Bueye. The volcano features a glacier and the Achibueno and Blanco rivers originate on the mountain.

<span class="mw-page-title-main">Igneous intrusion</span> Body of intrusive igneous rocks

In geology, an igneous intrusion is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and compositions, illustrated by examples like the Palisades Sill of New York and New Jersey; the Henry Mountains of Utah; the Bushveld Igneous Complex of South Africa; Shiprock in New Mexico; the Ardnamurchan intrusion in Scotland; and the Sierra Nevada Batholith of California.

<span class="mw-page-title-main">Lunar magma ocean</span> Theorized historical geological layer on the Moon

The Lunar Magma Ocean (LMO) is the layer of molten rock that is theorized to have been present on the surface of the Moon. The Lunar Magma Ocean was likely present on the Moon from the time of the Moon's formation to tens or hundreds of millions of years after that time. It is a thermodynamic consequence of the Moon's relatively rapid formation in the aftermath of a giant impact between the proto-Earth and another planetary body. As the Moon accreted from the debris from the giant impact, gravitational potential energy was converted to thermal energy. Due to the rapid accretion of the Moon, thermal energy was trapped since it did not have sufficient time to thermally radiate away energy through the lunar surface. The subsequent thermochemical evolution of the Lunar Magma Ocean explains the Moon's largely anorthositic crust, europium anomaly, and KREEP material.

<span class="mw-page-title-main">Tres Vírgenes</span> Complex of volcanoes located Mulegé Municipality, Mexico

Tres Vírgenes is a complex of volcanoes located in the Mulegé Municipality in the state of Baja California Sur, on the Baja California Peninsula in northwestern Mexico. This Volcano is part of a volcanic ridge that extends from Baja California towards the Guaymas Basin.

Igneous petrology is the study of igneous rocks—those that are formed from magma. As a branch of geology, igneous petrology is closely related to volcanology, tectonophysics, and petrology in general. The modern study of igneous rocks utilizes a number of techniques, some of them developed in the fields of chemistry, physics, or other earth sciences. Petrography, crystallography, and isotopic studies are common methods used in igneous petrology.

<span class="mw-page-title-main">Igneous rock</span> Rock formed through the cooling and solidification of magma or lava

Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.

The methods of pluton emplacement are the ways magma is accommodated in a host rock where the final result is a pluton. The methods of pluton emplacement are not yet fully understood, but there are many different proposed pluton emplacement mechanisms. Stoping, diapirism and ballooning are the widely accepted mechanisms. There is now evidence of incremental emplacement of plutons.

The Achala Batholith is a group of plutons in the Sierras de Córdoba in central Argentina. With a mapped surface of over 2500 km2 it constitutes the largest group of intrusions exposed in the Sierras Pampeanas. The oldest reference to the batholith dates to 1932.

<span class="mw-page-title-main">Red Hill Syenite</span>

The Red Hill Syenite is a layered igneous rock complex in central New Hampshire, about 20 mi (32 km) east of Plymouth. The Red Hill Syenite is part of the White Mountain magma series, which underlays the White Mountains of New Hampshire. Red Hill is roughly oval-shaped, covers just under 7.7 square miles (20 km2), and has a summit elevation of 2,028 feet (618 m).

References

  1. Dorais, Michel J.; Lira, Raul; Chen, Yadong; Tingey, David (1997). "Origin of biotite-apatite-rich enclaves, Achala batholith, Argentina". Contributions to Mineralogy and Petrology . 140 (1): 31–46. Bibcode:1997CoMP..130...31D. doi:10.1007/s004100050347. S2CID   129621632.