TY  - JOUR
A1  - Ferrero, Silvio
A1  - Braga, R.
A1  - Berkesi, M.
A1  - Cesare, Bernardo
A1  - Ouazaa, N. Laridhi
T1  - Production of metaluminous melt during fluid-present anatexis: an example from the Maghrebian basement, La Galite Archipelago, central Mediterranean
JF  - Journal of metamorphic geology
N2  - Garnet brought to the surface by late Miocene granitoids at La Galite Archipelago (Central Mediterranean, Tunisia) contains abundant primary melt and fluid inclusions. Microstructural observations and mineral chemistry define the host garnet as a peritectic phase produced by biotite incongruent melting at ~800 degrees C and 0.5GPa, under fluid-present conditions. The trapped melt is leucogranitic with an unexpected metaluminous and almost peralkaline character. Fluid inclusions are one phase at room temperature, and contain a CO2-dominated fluid, with minor H2O, N-2 and CH4. Siderite and an OH-bearing phase were identified by Raman and IR spectroscopy within every analysed inclusion, and are interpreted as products of a post-entrapment carbonation/hydration reaction between the fluid and the host during cooling. The fluid present during anatexis is therefore inferred to have been originally richer in both H2O and CO2. The production of anatectic melt with a metaluminous signature can be explained as the result of partial melting of relatively Al-poor protoliths assisted by CO2-rich fluids.
KW  - fluid inclusions
KW  - garnet
KW  - anatexis
KW  - nanogranites
KW  - melt inclusions
Y1  - 2014
U6  - https://doi.org/10.1111/jmg.12068
SN  - 0263-4929
SN  - 1525-1314
VL  - 32
IS  - 2
SP  - 209
EP  - 225
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -