RT Journal Article
T1 Gahnite, chrysoberyl and beryl co-occurrence as accessory mineralsin a highly evolved peraluminous pluton: The Belvís de Monroyleucogranite (Cáceres, Spain)
A1 Merino Martínez, Enrique
A1 Villaseca González, Carlos
A1 Orejana García, David
A1 Jeffries, Teresa E.
AB Gahnite (ZnAl2O4), chrysoberyl (BeAl2O4) and beryl (Be3Al2Si6O18) have been found as accessory minerals in the external, highly fractionated, leucogranitic unit within the Hercynian reversely zoned Belvís de Monroy pluton (westernmost part of the Montes de Toledo batholith, Cáceres, Spain). The highly felsic (SiO2 > 72 wt.%) and peraluminous (ACNK > 1.2) character of this leucogranite, together with the high content of some incompatible elements (F, Li, B, and P), seems to be a primary consequence of fractional crystallization in a magmatic closedsystem. The high Be contents and Zn/FeTotal ratio (>0.01) are relevant factors which have favoured the precipitation of these minerals. Moreover, the Si, Al, P, B, and F activities might be high, favouring the magmatic crystallization of such exotic mineral phases together with Be-rich cordierite, F-rich micas, sillimanite and Alrich phosphates. In fact, the interplay between the silica and alumina activities likely controls the stabilization and the preferential crystallization of gahnite + chrysoberyl or beryl + chrysoberyl assemblages in mm-sized microdomains. The P–T crystallization conditions are constrained by the muscovite and sillimanite stability fields and the minimum granite Al2O3-saturated solidus, and have been estimated at temperatures between 670 and 700 °C, and pressures between 1 and 2 kbar.
PB Elsevier Science B.V., Amsterdam
SN 0024-4937
YR 2013
FD 2013
LK https://hdl.handle.net/20.500.14352/43380
UL https://hdl.handle.net/20.500.14352/43380
LA eng
NO Ministerio de Economía y Competitividad de España
DS Docta Complutense
RD 7 abr 2025