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This precludes a major input of an unmodified, mantle-derived component, at the time of magma genesis. Nd isotopic contrasts between enclaves and hosts are 1 ε-Nd-unit at most. These data indicate broadly cogenetic origins for enclave-host systems, though some enclaves have slightly less "crustal" signatures than the enclosing granitoids.Web
Experiments designed to simulate the dissolution of alkali feldspar during magma mixing produced plagioclase mantles that are texturally and compositionally similar to those in some hybrid volcanic rocks. In hydrous dacite melt (69% SiO2) at 0.8 GPa, 850°C, orthoclase (Or93) and sanidine (Or30) partially dissolved and were mantled by sodic …Web
The origin of rapakivi feldspars is still a matter of active debate and a number of mechanisms have been presented to explain the formation of mantled feldspars. One model explains the origin of rapakivi texture by mixing of an alkali feldspar-rich felsic magma and a mafic magma, which increases the temperature of the felsic magma and …Web
The magma mixing origin of mantled feldspars. M. Hibbard. Geology. 1981; The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K-feldspar on plagioclase. Once this nucleation takes place there is a relatively straightforward process … Expand. 370.Web
Enclaves of igneous origin are also present in all major plutons except Carnmenellis, generally comprising < 1 vol.% of the granites. The most common type is intermediate in composition, with microgranular texture, and mineral compositions and textures consistent with an origin by magma mixing.Web
The generation of mantled feldspars is probably related to isothermal decompression and magma mixing, which is compatible with the εNdi signatures (−3.76 to −4.40).Web
The magma mixing origin of mantled feldspars. Contrib. Mineral. Petrol. (1981) W. Hildreth Gradients in silicic magma chambers: implications for lithospheric magmatism. Journal of Geophysical Research: Solid Earth (1981) H.E. Huppert et al. The generation of granitic magmas by intrusion of basalt into continental crust.Web
The magma mixing origin of mantled feldspars. M. Hibbard. Geology. 1981; The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K-feldspar on plagioclase. Once this nucleation takes place there is a relatively straightforward process … Expand. 368.Web
The magma mixing origin of mantled feldspars. M. Hibbard. Geology. 1981; The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K-feldspar on plagioclase.Web
Hibbard, M.J. (1981) The magma mixing origin of mantled feldspars. ... Magma mixing and crust–mantle interaction in the Triassic monzogranites of Bikou Terrane, central China: Constraints from petrology, geochemistry, and zircon U–Pb–Hf isotopic systematics. Journal of Asian Earth Sciences, Vol. 98, Issue., p. 320.Web
Mantled feldspars in some intrusive systems (i.e., "rapakivi granites") may form by a similar dissolution- and diffusion-controlled mechanism. Textural evidence of a similar origin …Web
A complex process involving crustal anatexis, magma recharging and mixing, and crystallization could have developed during the generation of the Dupangling rapakivi granites. An open-system magma chamber is hereby estimated to reveal the origin of rapakivi feldspars. 4.3.1. The role of magma recharging and mixingWeb
Petrographic features like resorption textures, quartz ocelli, and the poikilitic nature of the large K-feldspar grains enclosed within plagioclase indicate interaction and magma mixing/mingling processes in an open magma chamber. Bladed biotite and acicular apatite grains in MMEs are due to rapid crystallization during the magma …Web
The magma mixing origin of mantled feldspars. M. Hibbard. Geology. 1981; The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K-feldspar on plagioclase. Once this nucleation takes place there is a relatively straightforward process … Expand. 369.Web
In these (and other) volcanic examples (see Stimac and This study was prompted by our attempts to understand the origin Wark in press), rapakivi texture formed as a result of magma mix- of mantled feldspars in (a) dacites and rhyodacites from the 0.3 ing, which caused partial resorption of alkali feldspar that was 0.6 Ma Clear Lake volcanic ...Web
The origin of volcanic rapakivi feldspars has been attributed to magma mixing (Hibbard, 1981; McDowell, 1978; Stimac and Wark, 1992), although decompression during magma ascent has been theoretically proposed (Nekvasil, 1991). ... but did not study mantled feldspars or examine the processes of magmatic resorption. ... The magma …Web
They concluded that the texture was formed by mixing of magmas of slightly different composition. Dempster et al., 1991, Dempster et al., 1994suggested that rapakivi texture formed by exsolution and diffusion of components within K-feldspar, where the plagioclase-component diffused to the rim of the ovoid and the Or-component was …Web
In:Isachsen YW (ed) Origin of anorthosites and related rocks. NY State Mus Sci Serv Mem 18:99–110. Hewitt CH (1959) Geology and mineral deposits of the Northern Big Burro Mountains-Redrock area, Grant county, New Mexico. New Mexico Inst Min Tech Bull 60,151 pp. Hibbard MJ (1981) The magma mixing origin of mantled feldspars. …Web
Tectonic setting and origin of the Proterozoic rapakivi granites of southeastern Fennoscandia - Volume 83 Issue 1-2 ... The magma mixing origin of mantled feldspars. CONTRIB MINERAL PETROL 76, 158 –70.Google Scholar. Hubbard, ... Central India - An Example for Magma Mixing and Differentiation. Gondwana …Web
The magma mixing origin of mantled feldspars. M. Hibbard. Geology. 1981; The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K-feldspar on plagioclase. Once this nucleation takes place there is a relatively straightforward process … Expand. 370.Web
The feldspars are situated in the MMEs and near the host-enclave boundary. ... Hibbard MJ (1981) The magma mixing origin of mantled feldspars. Contrib Mineral Petrol 76:158–170. Article ... (2009) Magma mixing origin for the post-collisional adakitic monzogranitegranite of the Triassic Yangba pluton, Northwestern margin of the South …Web
The outcome of this study will help evaluate the role of magmatic processes (e.g., magma mixing) and subsolidus fluid-rock interaction in the generation of rapakivi feldspar. ... The magma mixing origin of mantled feldspars. Contrib. Mineral. Petrol. (1981) View more references. Cited by (0) View full textWeb
Abstract. The key to mantled feldspar genesis is epitaxial nuclea- tion of plagioclase on K-feldspar or K-feldspar on plagioclase. Once this nucleation takes place there is a …Web
The magma mixing origin of mantled feldspars. M. Hibbard. Geology. 1981; The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K-feldspar on plagioclase. Once this nucleation takes place there is a relatively straightforward process … Expand. 370. 1 Excerpt;Web
The magma mixing origin of mantled feldspars. Contributions to Mineralogy and Petrology 76, 158 –70.Google Scholar. Hibbard, M. J. 1991. Textural anatomy of twelve magma-mixed granitoid systems. In Didier, J. & Barbarin, B. (eds) Enclaves and Granite Petrology, 431 –44.Web
The porphyritic andesite consists of rapakivi feldspars, which are characterized by phenocrysts of alkali feldspar mantled by plagioclase rims. Results …Web
Origin of mantle (rapakivi) feldspars: experimental evidence of a dissolution- and diffusion-controlled mechanism ... Experiments designed to simulate the dissolution of alkali feldspar during magma mixing produced plagioclase mantles that are texturally and compositionally similar to ... Mantled feldspars from the Golden Horn batholith ...Web
The Quxu monzogranites have a magma crystallization age of ∼50 Ma. Some elements (e.g., Al, Sr, Cr and Ni) of the Quxu monzogranite and MMEs show scatter and no linear variations with increasing SiO 2, indicating that simple magma mixing between mafic and felsic endmembers is unconspicuous for the formation of the Quxu monzogranites. …Web
Hibbard MJ (1981) The magma mixing origin of mantled feldspars. Contrib Mineral Petrol ... The above features suggest the origin of KG by magma mixing. Furthermore, textures including quartz ...Web
1. Introduction. Magma mixing is an important process that occurs during magmatic evolution and is the main reason for the diversity of igneous rocks in subduction zones, orogenic belts and extensional tectonic settings (Hu et al., 2017, Plail et al., 2018, Sun et al., 2020).Hybrid magmas represent the results of mixing between at least two …Web
The magma mixing origin of mantled feldspars. Abstract. The key to mantled feldspar genesis is epitaxial nucleation of plagioclase on K-feldspar or K …Web
Initial quenching of a magma globule in felsic magma involves rapid temperature equilibration, which causes a high rate of nucleation of minerals precipitating from the enclave magma at the time, followed by a period of slow cooling, during which the nucleation and growth rates of later-crystallizing minerals are similar to the much slower ...Web
DOI: 10.1016/J.LITHOS.2016.09.016 Corpus ID: 132477639; Feldspar megacrysts from the Santa Angélica composite pluton — Formation/transformation path revealed by combined CL, Raman and LA-ICP-MS dataWeb
However, more such mantled alkali feldspars have to be reported from other magma mixing scenarios to validate our hypothesis. Based on petrographical observations and mineral chemical analyses, we infer that varying degrees of interaction between intrusive mafic and host felsic magmas occurred in the Kathalguri Pluton.Web
