Faciologia da Associação Vulcano-Plutônica Taquarembó, Cambriano do Escudo Sul-rio-grandense, RS - Brasil

WILSON WILDNER, EVANDRO FERNANDES DE LIMA, LUIZ FERNANDO DE ROS, LAURO VALENTIM STOLL NARDI

Resumo


The Taquarembo Plateau, situated in the southwestern part of Sul-rio-grandense shield, is part of Camaquã Basin, that was formed at the end of the post-collisional stage in Brasiliano/Pan-Africa event, Neoproterozoic in age. This plateau is composed of volcanic and shallow intrusions, related to a silica-saturated alkaline series, ranging from alkaline metaluminous basalt to comendiitic flows, known as Taquarembo Volcano-Plutonic Association. The faciological identification leads to the reconstruction of the volcanic pile, formed from the base to the top by: particulated flows (ignimbrites and reo-ignimbrites); ressedimented syneruptive deposits; surge and fall horizons, closely associated with alkaline metaluminous lava flows (basalts, mugearites, rhyolites); and peralkaline lava flows (comendiites), and shallow intrusions of quarz monzonite and syenite that crosscut the volcanic pile. The facies identification suggests a highly explosive volcanic regime, under sub-aerial condition, in a close association with the feeder necks.


Palavras-chave


volcanic sequences, Cambrian volcanism, volcanic textures.

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DOI: https://doi.org/10.22456/1807-9806.20179

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