Evolución microestructural y metamórfica de la zona de cizalla extensional de Berzosa-Riaza: la superposición de asociaciones minerales de Baja-P/Alta-T sobre una secuencia Barroviense

Abstract

A new integrated analysis of microstructural, metamorphic and U-Pb monazite age data, indicates that the Berzosa-Riaza shear zone (BRSZ) is a major D2 extensional structure associated with crustal-scale ductile extensional shearing and important decompression. Low-P/high-T metamorphism associated with thw D2 event overprints earlier barrovian metamorphic assemblages formedduring the Hercynian D1 compressional event. Qualitatively-derived P-T-t paths suggest that this syncollisional extension in the Somosierra sector of the Spanish Central System was associated with the major extensional collapse of the previously thickened Hercynian crust