J. Garcia-Sansegundo & J. Poblet write: Based on the relationships between the mesoscopic structures and the contact metamorphic porphyroblasts related to the Maladeta grano-diorite (Pyrenean Axial Zone), Evans et al. 1998 state that the batholith emplacement is coeval with the main Hercynian deformation phase (D2). This hypothesis was already suggested by Gleizes et al. (1997a, b) for the Hercynian granitoids located in the Pyrenean Axial Zone using the anisotropy of magnetic susceptibility. However, as pointed out recently (Laumonier 1997; Garcia-Sansegundo & Poblet 1997), this hypothesis does not take into account the cross-cutting relationships between the granitoids and some macrostructures showed by previous workers. In this paper, we will discuss the relative chronology of the Maladeta granodiorite and the surrounding Hercynian structures as well as some problems that arise from the geological map and cross section presented by Evans et al. 1998.

Evans et al. 1998 show a map and a cross section across the aureole (see Evans et al. 1998, figs 4 and 6) in which the main structures consist of a large, recumbent, south-facing fold deformed by smaller-scale, upright, south-facing folds belonging to the main phase (D2). Recent geological maps and cross sections across this region and adjacent areas are substantially different from the ones presented by Evans et al. 1998. Thus, previous studies do not describe the occurrence of recumbent, south-facing folds, but they evidence north-facing folds developed before the main phase (Poblet & Casas 1993, figs 2, 4, 6; Garcia-Sansegundo 1996, fig. 6). Both Dl and D2

First Page Preview

First page PDF preview
You do not currently have access to this article.