SYNTECTONIC ANATEXIS AND MAGMATISM IN A MIDCRUSTAL TRANSPRESSIONAL SHEAR ZONE - AN EXAMPLE FROM THE HERCYNIAN ROCKS OF THE EASTERN PYRENEES

Hercynian metamorphism and magmatism in the Cap de Creus peninsula (ea stern Pyrenees) occurred contemporaneously with non-coaxial deformatio n in a transpressive regime. An example of this has been taken from a migmatite complex in the northern coast. The studied area is formed by partially melted sillimanite schists together with two different suit es of igneous rocks: a calc-alkaline magmatic sequence, consisting of small granitoid bodies, and later peraluminous Leucogranites and pegma tites. All these rocks occur within a NE-SW- to E-W-trending sub-verti cal high-strain zone, where a first schistosity is tightly folded and transposed. The relations between folds and crenulation cleavage in th e metasediments and deformational fabrics in the granitoids and migmat ites provide good evidence for the penecontemporaneity of deformationa l processes. magmatism and migmatization. Further-more, the analysis o f cross-cutting relationships between different granitoids as well as the observation of their different degrees of deformation verifies tha t magmatism in this area took place as synkinematic consecutive intrus ions from the more basic magmas to the peraluminous acid dykes. (C) 19 98 Elsevier Science Ltd. All rights reserved.