Amphibole Granite Research Articles

Mineralogía y condiciones de cristalización en el complejo subvolcánico de Barcarrota (Badajoz, España)

A description of mineral chemistry from rocks of the subvolcanic Barcarrota Complex is made. This igneous massif consists of several sub-alkaline lithologies, namely olivine gabbros, diorites, quartz-monzonites and amphibole granites, as well as minor peralkaline granites. Physico-chemical conditions during magma crystallization are obtained on the basis of mineral data. Thus different geothermometers lead to the following crystallization temperatures: olivine gabbros (972-1.008° C), diorites (953-995° C), quartz-monzonites (801-833° C) and amphibole granites 750° C. The presence of illmenite as the sole Fe-Ti mineral in these rocks (except in the peralkaline types where it is magnetite), sugests that the fO2 was never higher than the MW buffer, decreasing continuously with the differentiation degree fram fO2= 1O -13.2 atm. for the olivine gabbros to 10 -18.87 atm. in the granites) Furthemore water played an important role during crystallization of the different magmas.

Sur l'extension des "durbachites" et autres roches basifiees au sein des gneiss de Sainte-Marie-aux-Mines dans les Vosges (Haut-Rhin)

Abstract So-called durbachites and related rocks within the Sainte-Marie-aux-Mines gneiss of the Vosges massif (Haut-Rhin, France) have been mapped. Their origin seems to be related to the nature of the original rock, their position relative to a nearby biotite-amphibole granite, and the proximity of a coarse two-mica granite at shallow depth. They are considered to have formed by desilication of leptynitic rocks and later feldspathization. Microsyenites which extend farther northward in the Urbeis gneiss at the margin of the amphibole granite represent magmatic counterparts of the durbachites.

Sur l'evolution du granite de Querigut (Ariege)

Abstract Discusses the genetic relationships between migmatites (amphibole granites and diorites with or without quartz) and basic rocks (melanocratic diorites, norites, hornblendites, peridotites) in the peripheral zone of the Querigut massif in the French Pyrenees. The massif is composed for the most part of normal biotite granites. The basic masses included in the migmatites are considered local segregation products formed in highly contaminated zones during a late stage of migmatization.