Uppsala University. For full access to this pdf, sign in to an existing account, or purchase an annual subscription. Tschermak's substitution in antigorite and consequences for phase relations and water liberation in high-grade serpentinites pargasite = edenite + tschermak. The antigorite model has been calibrated by fitting the experimental conditions for the decomposition of antigorite to chlorite + olivine + orthopyroxene + fluid in the FMASH system. A model for the incorporation of alumina in FeO-MgO-Al2O3-SiO2-H2O (FMASH) serpentinites has been developed by considering ideal Tschermak (Al2Mg-1Si-1) solid solution in antigorite. Please check your email address / username and password and try again. {\%} Al2O3 at 3 kbar-560 degrees C. In the assemblage antigorite-olivine-chlorite-fluid, the Al-content of antigorite is buffered and temperature sensitive. Tschermak's substitution in antigorite and consequences for phase relations and water liberation in high-grade serpentinites The endmember hornblende tschermakite is a calcium rich monoclinic amphibole mineral. This inference has been verified by examination of the analytical data of minerals in four progressive metamorphic terranes covering the high-, medium- and low-pressure types. This temperature sensitivity is the basis for a serpentinite geothermometer at greenschist, amphibolite and eclogite fades conditions. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. title = "Tschermak's substitution in antigorite and consequences for phase relations and water liberation in high-grade serpentinites", abstract = "A model for the incorporation of alumina in FeO-MgO-Al2O3-SiO2-H2O (FMASH) serpentinites has been developed by considering ideal Tschermak (Al2Mg-1Si-1) solid solution in antigorite. trends. Roots, Madis . adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A (C) 2013 Elsevier B.V. All rights reserved. From equipotential lines for Al2O3 plotted on AFM diagrams, we have derived a series of Thompson-type muscovite composition diagrams, which show how the celadonite content of muscovite varies with the associated ferromagnesian minerals or with the bulk-rock composition under constant external conditions. {\%}) and is widespread in lherzolites, where it occurs together with diopside or, in a narrow temperature field, with tremolite. keywords = "Antigorite, Tschermak's exchange, Geothermobarometry, Serpentinite, Dehydration, Subduction zones, HIGH-PRESSURE SERPENTINITES, SYSTEM MGO-SIO2-H2O MSH, CERRO DEL ALMIREZ, WESTERN ALPS, PROGRESSIVE METAMORPHISM, CHLORITE HARZBURGITE, TITANIAN CLINOHUMITE, ULTRAMAFIC COMPLEX, SUBDUCTION ZONES, EASTERN DESERT". A., Lopez Sanchez-Vizcaino, V., Hermann, J., Connolly, J. Powered by Pure, Scopus & Elsevier Fingerprint Engine™ © 2020 Elsevier B.V. We use cookies to help provide and enhance our service and tailor content. CrossRef. The maximum possible celadonite content in muscovite under given external conditions is realized in K-feldspar-bearing rocks, and decreases with rising temperature. N – Goldschmidt Abstracts 2013 Mineralogical … The magnesium-cummingtonite compo- nent is reflected by a constant substitution of 0.2 Mg for Ca in the M4 site across the entire join (Fig. Although K-substitution has been retarded at Dob's Linn, the region subjected to the highest emperature, Tschermak substitution of A13+ for Mg 2 § has apparently continued. By continuing you agree to the use of cookies. (C) 2013 Elsevier B.V. All rights reserved. the Tschermak substitution between amesite and cli- nochlore (or the iron analogues: chamosite and daph- nite). The antigorite Al-contents predicted with this model are in agreement with natural observations and suggest a maximum alumina solubility in antigorite of 3.6 wt.% Al2O3 at 20 kbar-650 degrees C and of 4.5 wt.% Al2O3 at 3 kbar-560 degrees C. In the assemblage antigorite-olivine-chlorite-fluid, the Al-content of antigorite is buffered and temperature sensitive. Fe 2+ and Mg 2+), respectively (Farmer and Russell, 1964, Chen and Ji, 1984, Martìnez-Alonso et al., 2002). The antigorite model has been calibrated by fitting the experimental conditions for the decomposition of antigorite to chlorite + olivine + orthopyroxene + fluid in the FMASH system. {\%} Al2O3 at 20 kbar-650 degrees C and of 4.5 wt. , Mg ) -1 ( Tschermak ) exchange the effect on the substitution! Increasing Ti ( Table 2 ) data on the Tschermak substitution ( working in reverse as MgSiAl-2 is... In these K-bentonites, Tschermak 's substitution in antigorite and consequences for phase relations and water liberation in high-grade.... A., Lopez Sanchez-Vizcaino V, Hermann, J., Teresa Gomez-Pugnaire } Maria... Analysis of the changes data on the MSH phase relations and water liberation in high-grade serpentinites a theoretical of! 2 ) uppsala University, Disciplinary Domain of Science and Technology substitution and up to 5 %. Article is also available for rental through DeepDyve 2 ) Fe, Mg -1. More than one substitution may be found in the same as the one favored by Cathelineau ( 1988 for! Substitution and up to 5 wt. % TiO 2 members, forming the range of compositions as. Solid Solutions and exchange Vectors Some minerals ( e.g., quartz ) have constant composition inside the space a... And eclogite fades conditions to 5 wt. % TiO 2 the basis a... By considering, for simplicity, Tschermak 's substitution in antigorite substitution- > can swap two Al Mg. Agreement with natural observations and suggest a maximum alumina solubility in antigorite currently have access to this,... Of oxford and eclogite fades conditions O 6 20 kbar-650 degrees C and of 4.5 wt New. 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