High temperature - Low pressure tectonites from the Boa Fé Fault Zone (Évora Massif, Ossa Morena Zone, Portugal): Evidences for transtensional tectonics

• Autores: M. Chichorro, M. Francisco Pereira, Arturo Apraiz Atutxa, J.B. Silva
• Localización: Geogaceta, ISSN 0213-683X, Nº. 34, 2003, págs. 43-46
• Idioma: inglés
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• Resumen

  • Partial melting in the Évora Massif (Ossa-Morena Zone) occurred contemporaneously with non-coaxial deformation in a transcurrent regime.

    An example of this fact has been taken from studied partially melted biotite-sillimanite-K-feldspar-andalusite-cordierite tectonites from the Boa Fé Fault Zone. These HT-LP (- 2,5-3.5 kbar and 550°-750°C) mylonitic rocks characterized by a steeply dipping to SW foliation (N30º-55°W, 70º-80ºSW) and gently dipping to SE stretching lineation (10°-20° to SE) associated to sinistral sense of movement. Transtensional tectonics ís suggested to explain how the Évora High-grade Metamorphic Terrain migmatites were exhumed in parallelism with the orogen-trend.