Bull. Minéral. (1987), 110, 235-247
Physicochemical and crystal-chemical controls on accessory mineral paragenesis in granitoids : implications for uranium metallogenesis
by Michel CUNEY and Marc FRIEDRICH
Centre de Recherche sur la Géologie de l'Uranium et G. S. C.N.R.S.-CREGU B.P. n° 23, 54501 Vandœuvre-les-Nancy Cedex, France.
Paramètres physicochimiques et cristallochimiques contrôlant les paragenèses de minéraux accessoires dans les granites : implications en métallogénie de l’uranium.
I. Introduction
Several types of accessory mineral paragene-ses have been described in granitoids and, espe¬ cially, in U and Th enriched granitoids. Accor¬ ding to mineralogical studies carried out on granite samples mostly from the European Her-cynian chain, Cuney et al. (1979) and Pagel (1981, 1982), have identified two contrasting ty¬
pes of parageneses. Peraluminous granites, with a CaO content generally lower than 1 wt % are characterized by the association of monazite with low thorium-uraninite ± xenotime. Ilme-nite, anatase ± pyrite are the main accessory Fe-Ti minerals. High Ca (> 1 wt %) metalumi¬ nous monzonitic granites, designated as subalka-line granites, (Pagel and Leterrier, 1980 ; Pagel, 1981), are characterized by the association of
© Société française de Minéralogie et de Cristallographie, Paris, 1987.
