profile. The igneous rocks have tightly interlocking mineral crystals. However, the Indawgyi gabbros are in the same broad structural zone as the subduction-generated jadeite and eclogite at Hpakant, suggesting that the gabbros are related in some way either to the formation of oceanic lithosphere or to a stress system that allowed ascent of serpentinized upper mantle. If the quantity of pyroxene increases in anorthosite, the rock grades into gabbro and vice-a-versa. Interlocking crystals are formed. Figure 2.8. Which scientific term names rocks formed from magma? Photomicrograph of thin section showing large phenocryst of deformed plagioclase (labrodorite) in fine-grained pyroxene and plagioclase-rich groundmass in massif Anorthosite. As the lava hurtles through the air it cools and the gases escape leaving the rock full of holes. A. rate of cooling of the magma or lava B. rate of tectonic uplift C. specific gravity of the magma or lava D. composition of the rock surrounding the magma 9.Igneous rock originates when hot, molten material called cools and crystallizes. It is composed of Ca-rich Plagioclase (Labradorite), Mg-rich Orthopyroxene/Hypersthene (Enstatite), and Olivine. Norite with Olivine is olivine norite. In the thicker gabbros of the Platta nappe, compositions range from olivine gabbros to differentiated Fe–Ti gabbros. 18.8A). The main difference between them is the process through which it formed and texture. Dolerite and Diabase are both mafic igneous rocks having same mineralogical composition, but differ in formation. The Cu and Ni concentrations fall through the QGAB Unit to background levels in the overlying GRAN (Fig. Throughout the Alpine ophiolites, gabbros intruded into the serpentinized peridotites do not occupy more than 5% of the total volume. Lava is the term given to magma once it reaches the Earth’s surface, usually in the form of a volcanic eruption. Partial melts of eclogites are SiO2-oversaturated, with near-solidus melts ranging from andesitic to dacitic (Yaxley and Green, 1998; Pertermann and Hirschmann, 2003). 2.4) is formed by simultaneously extended crystallization of bright (leucocratic) and dark ferromagnesian minerals that are compact, solid, and tough. Figure 18.9. Extrusive igneous rocks are formed when molten magma spill over to the surface as a result of a volcanic eruption. Rocks formed by cooling of magma within the crust are called 'Plutonic rocks'. Haldar, in Platinum-Nickel-Chromium Deposits, 2017. Many anorthosite outcrops are transected by thin veins and stringers of quartz and feldspar, manifesting incipient disaggregation by the granitic protolith to the host quartzofeldspathic gneiss. All gradations exist from cumulate-textured rocks dominated by bronzitic orthopyroxene (crystals to 1 cm), with lesser clinopyroxene and rare olivine and chromian spinel (Fig. 4.24). What unit is electrical energy typically measured in on energy bills? Given their single component nature and unambiguous igneous protolith, such leucogabbros are more properly afforded the title of Australia's oldest rocks. Magma is a form of molten rock that exists below the Earth’s surface. The magma, which is brought to the surface through fissures or volcanic eruptions, rapidly solidifies.Hence such rocks are fine-grained or even glassy.Basalt is the most common extrusive igneous rock and forms lava flows, lava sheets and lava plateaus. The Sudbury Gabbro is an important inclusion type and host-rock to the ore deposits at Totten Mine on the Worthington Offset, and at Kelly Lake in the southern part of the Copper Cliff Offset. Anthony I.S. Brainly User. The rocks usually display intersertal and intergranular texture. Which scientific term names rocks formed from magma? ... Get the Brainly App Many of the occurrences are developed up to 50 km WSW of Sudbury, and the textures are typical of magmatic sulfides formed from the parental magma of the Sudbury Gabbro intrusions. The gabbros are cut locally by dolerite dykes (Fig. They are closely associated in the field, for example in the Bole River area (Yan, 1979). The accessory minerals are Chlorite, Uralite, and Calcite. Photomicrograph showing large deformed plagioclase phenocryst embedded in finer matrix of ferromagnesian minerals in gabbro. The magma which is inform of molten rock is stored in the earth's crust, i.e below the earth surface, while the lava can be described as a magma, i.e molten rock found on the surface of the earth's crust. Samples of the Manfred Complex near Mount Narryer gave an Sm–Nd whole-rock isochron age of 3680 ± 70 Ma and a Pb–Pb isochron age of 3689 ± 146 Ma (Fletcher et al., 1988). It means that it formed as magma cooled slowly in the crust. — two different crystal sizes — Coarse and fine crystals are found together. Dolerite is heavy with specific gravity ranging between 2.9 and 3.3. Igneous rocks with similar composition are basalt (extrusive equivalent of gabbro) and diabase (the same rock type could be named dolerite or microgabbro instead).. Gabbro with large augite phenocrysts embedded in white plagioclase. FIGURE 4.19. Photograph of drill core (Norite) cutting across the mafic and ultramafic layered igneous intrusive complex, being explored for chromium and platinum group of minerals at Boula-Nausahi, Orissa, India. On weather magma cools slowly underground, so does the silica content as quartz/coesite Melts ( Yaxley and Brey 2004. 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