Diques piroclásticos en el Complejo Volcánico Marifil

GONZÁLEZ, SANTIAGO N.; GRECO, GERSON A.

Córdoba

Congreso; Congreso de Mineralogía, Petrología Ígnea y Metamórfica, y Metalogénesis: XIII MINMET y IV PIMMA; 2019

COMPETRO-AGA

Pyroclastic dykes in the Marifil Volcanic Complex. The acidic rocks from the Marifil Volcanic Complex (MVC) represent the Jurassic magmatism from the northeast Patagonia. The emplacement and eruption of this magmatism was controlled by northwest extensional fractures. The stratigraphic succession of the MVC starts with epiclastic deposits follow by thick pyroclastic sheets. Domes, lava flows, dykes and stocks represent the final stages of the Jurassic magmatic event. In Rincon de Paileman, pyroclastic dykes have been recognized and has been related to the pyroclastic eruptions of the MVC. Based in this relation between the pyroclastic dykes and the violent eruptions, a proposal about the evolution of the MVC is made. It started with sedimentation in depocenters where their development was control by northwest extensional fractures. When the extensional fractures reach cortical magmatic reservoirs, it produces a massive degasification leading to violent eruptions and thedeposition of thick pyroclastic levels. The pyroclastic dykes might have been the feeders of those eruptions. After degasification the magmatic activity turns less violent producing coherent magma bodies as domes, dykes and stocks. The successive magmatic pulses might have used the northwest structures as channels producing pyroclastic and magmatic dykes with the same orientation. These channels might have also worked as feeders for the eruptive products. Considering this new data and the proposed model, the idea of a fissural Jurassic volcanism in the northeast Patagonia is reinforced.