The processes that control leucosome compositions in metasedimentary granulites: perspectives from the Southern Marginal Zone migmatites, Limpopo Belt, South Africa. In north-central Bhutan northeast of Thimphu, Swapp and Hollister (1991) studied metamorphic textures and assemblages in the higher levels of the HHC (Tibetan Slab), which they divided into a Lower Structural Level (LSL) and a Higher Structural Level (HSL) zone. Laixi Tong, Zhao Liu, Zheng-Xiang Li, Xiaohan Liu, Xin Zhou, Poly-phase metamorphism of garnet-bearing mafic granulite from the Larsemann Hills, East Antarctica: P-T path, U-Pb ages and tectonic implications, Precambrian Research, 10.1016/j.precamres.2017.12.045, (2017). The second tectonic phase involved the intrusion of the St Peter Suite (1630–1608 Ma) as a continental magmatic arc, and probably reflects accretion of continental blocks from the west, now buried beneath the Phanerozoic Eucla Basin. Granulite facies. Mesoproterozoic granulite and amphibolite facies gneisses of the Musgrave Block were overprinted during the Petermann Orogeny (-550 Ma)with zones of high strain concentrated along broadly east-west trending shear zones. Working off-campus? Concentrated aqueous solutions of strong electrolytes, including (Na,K)Cl, would have low aH2O, as would CO2-rich fluids. Granulite facies and eclogite xenoliths are plentiful in eastern Australia and Pearson & Oâ ReiUy demonstrate, on the basis of detailed petrography and geochemistry, that the xenoliths come from a depth of 35-75 km. Conditions during the formation of granitic magmas by crustal melting – hot or cold; drenched, damp or dry?. New approaches to crustal evolution studies and the origin of granitic rocks: what can the Lu-Hf and Re-Os isotope systems tell us?. The main ocean closure was probably some where in ice-covered central East Antarctica within inferred blocks of 1.2–0.8 Ga mafic granitoids. Metamorphism and partial melting of high-pressure pelitic granulites from the Qianlishan Complex: Constraints on the tectonic evolution of the Khondalite Belt in the North China Craton. Grujic et al. The Araçuaí Orogen is subdivided by the Abre Campo Shear Zone into two tectonic domains - the internal (eastern) and the external (western) (Figure 1b). mean1 Median ±1σ 1 Archaean gneisses 95 3000– 2500 Dominantly tona-litic to granitic gneisses Early Proterozoic (c. 2.0–1.8 Ga) amphibo-lite- to granulite-facies metamorphism. Petrological studies of metagabbros from the southwest periphery of the Biligirirangan Block reveal clockwise prograde and retrograde metamorphism in a subduction zone setting at a HP of 18–19 kbar and temperature of ~840°C (Ratheesh-Kumar et al., 2016). The granulite-facies metamorphism with peak P-T conditions at 718–729 ºC and 0.46–0.53 GPa is characterized by an anticlockwise P-T path. The model endorses that the EGMB–south represents a fraction of an exotic terrane that was transferred to proto-India in the late Paleoproterozoic (1.68–1.6 Ga). Isotopic constraints on fluid infiltration from an eclogite facies shear zone, Holsenøy, Norway. The contribution of charnockite magmatism to achieve near-ultrahigh temperatures in the Namaqua–Natal Metamorphic Province, South Africa. With the recognition that much of the intrusion, metamorphism, and deformation in the Buller and Takaka terranes (‘Tuhua Orogen’) occurred during the Cretaceous (of ‘Rangitata’ age), the orogen terminology became obsolete. Very high density CO2 associated with ultrahigh-temperature metamorphism in the Eastern Ghats granulite belt, India. The greenschist–amphibolite facies boundary (line 2, in Figure 5) is characterized in mafic rocks by the relatively abrupt increase of the calcium (anorthite)-content of plagioclase and by a simultaneous increase of the tschermak- and edenite-content of amphibole. The Yixingzhai granitoid plutons are chemically similar to the Hengshan TTG gneisses, but are only metamorphosed to greenschist to lower-amphibolite facies and are less deformed, locally preserving igneous textures. Based on the tectonic setting of the Pedra Dourada Granulite, this P-T path could be related to crustal thickening during the Transamazonian tectonothermal events (2,1-2,0 Ga) or the Brasiliano tectonothermal events (590-574 Ma) (Noce et al., 2007). de Wit’s intra-oceanic model; e.g., 1998). Anatexis during High-pressure Crustal Metamorphism: Evidence from As it is likely that some of the metamorphosed dykes belong to the 1.14 Ga- The formation of staurolite and the breakdown of chloritoid are generally considered to reflect the greenschist–amphibolite facies transition in pelitic rocks. A – type granite this type is formed from per-alkaline to alkaline magma (Al2O3 < Na2O + K2O) which forms Alkali Feldspar Granite from partial melting of continental crust and granulite rocks or fractionation in the crust. 4.4a). TRK Chetty, in Proterozoic Orogens of India, 2017. Generally, the rocks of the South Delhi Terrane are marked by amphibolite facies metamorphism and multiple stages of folding. Retrograde processes in migmatites and granulites revisited, Large‐scale fluid infiltration, metasomatism and re‐equilibration of Archaean basement granulites during Palaeoproterozoic thrust belt construction, Ungava Orogen, Canada. On the other hand, the style of crustal evolution during the Palaeoproterozoic differs significantly not only from that in the Archaean, but also from that in the Phanerozoic. A. Feenstra, G. Franz, in Reference Module in Earth Systems and Environmental Sciences, 2015. The earlier stage (c. 1160–1120 Ma) produced granulite facies assemblages in the Parry Sound domain and upper amphibolite facies assemblages in the Parry Island thrust sheet. The assemblage is typical of what is formed in conditions corresponding to an area on the two dimensional graph of temperature vs. pressure (See diagram in Figure 1). Metamorphism and Plate Tectonics At present, the geothermal gradients observed are strongly affected by plate tectonics. Experimental Study of the Melting Reaction and Genetic Mechanism of Mineral Phase Transformation in Granulite Facies Metamorphism. It has been regarded as consisting of three tectonic events and dates from ∼1850 to ∼1690 Ma. basins and oassive margins; thick sediments create enough t and p for recrystallization in lower layers, gradient- normal, facies- zeolite (relatively low t and p) ... facies- greenschist, amphibolite, granulite. In the early 1980s it was realized that the Mesozoic Rangitata Orogeny was probably a composite of an older subduction-related event and a younger extension-related event. Charnockitic alteration: evidence for CO2 infiltration in granulite facies metamorphism. 322. Water budget and partial melting in an Archean crustal column: example from the Dharwar Craton, India. Learn more. The original eclogite-facies mineral assemblage in the mafic rocks has been strongly overprinted by granulite facies metamorphism at 750 C and 0.7–0.8 GPa. At the eastern margin of the Gawler Craton, orthogneiss of the Miltalie Gneiss (∼2003 Ma) is unconformably overlain by shallow-water continental shelf deposits. Retrograde melt–residue interaction and the formation of near‐anhydrous leucosomes in migmatites. 2012; and references therein). The latest, most widespread and intense event at c.1150 Ma gave rise to low-P granulites which record an anticlockwise P-T path and were accompanied by gneissic granite and charnockite. The postkinematic mineral assemblages, however, formed at around 640°C and 6 kb. Oxygen Fugacity and Water Activity during Thermal Peak and Retrogression of Granulites around the Sarvapuram Area, Karimnagar Granulite Terrane, Andhra Pradesh, India. High-pressure partial melting and melt loss in felsic granulites in the Kutná Hora complex, Bohemian Massif (Czech Republic). The steep mélanges may represent zones of strike-slip deformation. Crustal melting and melt extraction, ascent and emplacement in orogens: mechanisms and consequences. Pan-African extension and near-isothermal exhumation of a granulite facies terrain, Dronning Maud Land, Antarctica - Volume 141 Issue 6. Divergent boundaries are characterized by a rift in the surface of the earth along the midocean ridges. Features of the amphibolite–granulite facies boundary (line 3, in Figure 5) and the lower limit of the greenschist facies (line 1, in Figure 5) have been briefly discussed. The full text of this article hosted at is unavailable due to technical difficulties. 20 C) consistent with granulite facies metamorphism occurring contemporaneously with eclogite facies meta-morphism along strike to the northeast. Orthopyroxene‐bearing, mafic migmatites at Cone Peak, California: evidence for the formation of migmatitic granulites by anatexis in an open system. Tourmaline is associated with leucocratic granite variety. The Namaqualand Metamorphic Complex contains granulite facies rocks formed in two or more thermotectonic cycles during the mid-Proterozoic. Following accretion to the North Australian Craton, the site of subduction may have moved to the south-western Gawler Craton (Figure 4) with the development of the first tectonic episode of the Kararan Orogeny (1710–1670 Ma) and the intrusion of voluminous granitic rocks of the Tunkillia Suite in a possible back-arc setting. Anatectic migmatites in medium‐ to low‐pressure granulite facies metasediments exposed in the Larsemann Hills, East Antarctica, contain leucosomes with abundant quartz and plagioclase and minor interstitial K‐feldspar, and assemblages of garnet–cordierite–spinel–ilmenite–sillimanite. This model, combined with the natural observations, suggests that it is possible to form granulite facies assemblages without participation of external fluid and without major extraction of silicate melt. Also, unlike in the LSL, the compositional zoning in the rim and a homogeneous compositional picture in the core region of garnet, according to Swapp and Hollister (1991), suggest that such P-T conditions were achieved during cooling from a temperature of at least 650°C (probably near 700°C). Miyashiro (1961) proposed five facies series, most of them named for a specific representative “ type locality” The series were: 1. Episodes of tectonic activity were previously described as orogenies. Tectonics Metamorphic Facies Metamorphism And Plate Tectonics If you ally craving such a referred metamorphic facies metamorphism and plate tectonics book that will present you worth, get the definitely best seller from us currently from several preferred authors. (HP) granulite facies and ultrahigh temperature is sparsely pre-served but widely distributed in Phanerozoic orogenic belts and Precambrian cratons (e.g. This is mostly due to the strong dependence of the stable assemblages on the redox conditions prevailing during high-pressure metamorphism. Lamb and Valley, 1984; Crawford and Hollister, 1986; B. R. Frost and C. D. Frost, 1987; Newton, 1995; Aranovich and Newton, 1996, 1997, 1998, and numerous references cited therein). Contrasting behaviour of rare earth and major elements during partial melting in granulite facies migmatites, Wuluma Hills, Arunta Block, central Australia. Buchan or Abukuma Facies Series (low -P regional) 3. Figure 6.12. Geochronology and geochemistry of the enderbite series in the Lapland Granulite Belt: generation, tectonic setting, and correlation of the belt11NORDSIM Publication No. Granulites and charnockites of the Gruf Complex: Evidence for Permian ultra-high temperature metamorphism in the Central Alps. Although the real reasons for the different evolution of the belts remain unknown, it is clear that this difference played a fundamental role in crustal evolution. Prograde and retrograde reactions, garnet zoning patterns, and accessory phase behaviour in SW Finland migmatites, with implications for geochronology. Equilibria involving melt and solid phases are effective buffers of aH2,o. Silica-undersaturated spinel granulites in the Daqingshan complex of the Khondalite Belt, North China Craton: Petrology and quantitative P–T–X constraints. Garnet-bearing paragneiss from the Biligirirangan massif in the southern Karnatak. Fluid-rock interaction during high-grade metamorphism: Instructive examples from the Southern Marginal Zone of the Limpopo Complex, South Africa. All the tectonothermal events in the region including the UHT metamorphism can be considered as part of this accretionary process. Melting, carbonic fluids and water recycling in the deep crust: an example from the Limpopo Belt, South Africa. Seemingly disparate temperatures recorded in coexisting granulite facies lithologies. During this final assembly of Gondwana, the orogen was further deformed through thrusting and strike-slip shearing of the Rayner Complex against the Archean Napier Complex and the EGMB against the eastern margin of Archean Dharwar/Bastar cratons, (5) 0.3–0.2 Ga Permian–Triassic: the conjugate margins were crossed by a system of rift valleys, which accumulated the Gondwana succession of basal glacial sediments followed by coal measures and red beds, (6) 0.16–0.14 Ga Jurassic-Cretaceous: after preliminary rifting, continental breakup along the EGMB–Rayner complex, (7) to 0 Ma: the newly formed margins accumulated onlapping drift successions. Sodium is transferred from feldspar to amphibole and mica (paragonite). Metamorphic rock - Metamorphic rock - Pressure-temperature-time paths: Interaction between metamorphic petrologists and geophysicists in the 1980s led to the realization that each metamorphic rock follows its own unique path through pressure- (depth-) temperature space during metamorphism and that these paths bear little or no resemblance to steady-state geotherms. These facies are found in crustal tectonic setting or subduction zone. They also observed that reaction textures and geothermobarometry indicate high-temperature decompression of the upper portion of the Tibetan Slab to nearly 4 kb from a higher pressure. Max Wigley (2009): Phase relations of osumilite and reaction processes in granulite facies rocks from Namaqualand, South Africa. However, the highest grade rocks in sillimanite (±cordierite) zone of Pecher and Le Fort (1986) containing leucogranites were shown by Gansser (1983) under sillimanite–granulite facies. Felsic and bimodal volcanics and interlayered metasedimentary rocks of the Myola Volcanics and the Broadview Schist, and the Peake Metamorphics were deposited on the Gawler Craton ∼1790 Ma, contemporaneous with syntectonic granitic rocks of the Lincoln Complex. The preservation of anhydrous assemblages and the restricted distribution of late hydrous minerals suggest that retrograde reaction between hydrous melt and solids did not occur and that H2O in the melt was released as vapour on crystallization. Use the link below to share a full-text version of this article with your friends and colleagues. A metamorphic facies is a set of mineral assemblages in metamorphic rocks formed under similar pressures and temperatures.
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