MAGMATIC PULSES IN IBERIA DURING PANGEA AMALGAMATION: COLLISION, EXHUMATION AND OROCLINE DEVELOPMENT IGNEOUS FINGERPRINTS

One of the main characteristics linked to the amalgamation of Pangea in the western European Variscan belt is the presence of a large amount of igneous intrusive and volcanic rocks spanning in age from 350 to 295 Ma. Nowadays the time constraints and their relation with the collisional processes are subject of intense debate. New LA-U-Pb-ICP-MS geochronological data from the Tormes Dome and the Cantabrian Zone in Iberia, toghether with other recent available ages in surrounding realms, provide important constraints in understanding the timing and the involved large-scale processes that shaped Pangea. The recent new geochronological data suggest the episodicity of the main igneous pulses present in Iberia which can be correlated to major tectonic events during Pangea amalgamation. The three main identified pulses range in age from: i) 350-400 Ma, recording the effects of the Variscan collision and the exhumation of the subducted passive margin of Gondwana: ii) 325-318 Ma, reflecting the orogenic collapse of the Variscan orogen that stitched Pangea; and iii) 310-290 Ma, related to the magmatic effects of the orocline development and coeval mantle replacement in the core of Pangea. In addition, the abundance of inherited xenocrystic zircons present in the analysed samples shed light in the tectonic events that pre-dated the Variscan collision and also in the nature of the different terranes involved.