Extrusive rock - Wikipedia
Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. [1] . In contrast, intrusive rock refers to rocks formed by magma which cools below the surface. [2]
Metallic Ore Deposits Associated With Mafic to ... - ScienceDirect
2018年1月1日 · Thermal plumes impinging on the crust accompanied by decompression melting may have been responsible for the generation of the mafic magma, with extrusion of strongly fractionated felsic magma being the only volcanic expression. Ni-Cu-PGE deposits occur in a number of plate tectonic settings (Table 3.1).
Mafic magma-driven magmatic processes and ... - GeoScienceWorld
2022年6月23日 · The magmatic processes related to construction and modification of the Buya pluton can be interpreted from the structures and textures preserved in the rocks as well as from petrographic evidence. The fundamental control, or driver, of many of these processes appears to be mafic magma influx.
Geochemical characteristics of mafic and ultramafic rocks from …
2018年3月1日 · Ningthoujam et al. (2012) suggested a Mid Oceanic Ridge (MOR) setting for the origin of the NHO belt. In this paper, we present the results of petrological and geochemical characteristics of the mafic and ultramafic units from the NHO and discuss on the origin and tectonic settings of these rock types. 2.
Volcanic passive margins: another way to break up continents
2015年10月7日 · Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic and represent distinctive features of Larges...
Southward extrusion of eclogite-bearing mafic–ultramafic bodies …
2004年8月30日 · Several mafic rock masses, which have experienced eclogite facies metamorphism, are distributed in flat-lying non-eclogitic schists in an intermediate structural level (thermal core) of the Sanbagawa belt.
The Significance of Magnetic Fabric in Layered Mafic-Ultramafic ...
2015年1月1日 · With studies of layered mafic-ultramafic intrusions currently proceeding at unprecedented (micro-)scales of textural and geochemical detail, AMS offers petrologists a unique approach to investigating the microstructure of cumulates and the textural complexity they exhibit.
Textural and micro-analytical insights into mafic–felsic interactions ...
2018年4月7日 · We examine mafic inclusions of two compositional lineages (tholeiitic and calc-alkaline) from deposits of the 25.4 ka Oruanui eruption (Taupo, New Zealand). 2-D quantitative textural data from analysis of back-scattered electron images reveal a marked diversity in the groundmass textures of the inclusions, including median crystal sizes ...
Mafic and Felsic - SpringerLink
2020年12月13日 · The adjective mafic refers to a silicate mineral or rock (magmatic, either intrusive or extrusive) having a chemical composition rich in iron and magnesium and relatively poor in silicium. It corresponds to the older term basic as in basic rock. During crystallization of magma at high temperatures, a magmatic rock tends to concentrate firstly ...
Mafic High‐Pressure Rocks Are Preferentially Exhumed From …
2018年7月31日 · We conclude that the discrepancy between the rock record and thermal models is best explained by preferential exhumation of subducted mafic rock from warm subduction settings where higher temperatures lead to more efficient thermally activated creep and fluid-induced buoyancy and mobility to facilitate exhumation.