Fig. 3From: Discovery of Ordovician–Silurian metamorphic monazite in garnet metapelites of the Alpine External Aiguilles Rouges MassifTh–U–Pb CHIME model ages of monazite in the Col de Bérard region of the Aiguilles Rouges Massif. Total PbO versus ThO2* (wt%) isochron diagrams; ThO2* is ThO2 + UO2 equivalents expressed as ThO2, after Suzuki et al. (1994). Isochrons are calculated from regression forced through zero as proposedby Montel et al. (1996). Isochron ages match weighted average ages with error calculated according to Ludwig (2001). The MSWD values refer to 95% confidence interval. Age bars are given in Ma. a, b Mylonitic garnet gneisses with Ordovician and Variscan (Carboniferous) monazite ages. c–f Variscan (Carboniferous) monazites in garnet-bearing micaschists. Pre- and post-Variscan monazite ages and data from monazite enclosed in garnet are markedBack to article page