14C AGES OF THE LAST ERUPTIVE STAGE OF FAIAL ISLAND CALDEIRA VOLCANO

Faial is one of the nine islands that form the Azores archipelago in the North Atlantic, characterized by a complex geodynamic setting dominated by the triple point where the North American, Eurasian, and African lithospheric plates meet. Faial Island comprises two central volcanoes and two basaltic fissure systems. The oldest central volcano is the Ribeirinha Volcano, on the northeast sector of the island. It is an extinct volcano, extensively dissected by the regional distensive faults of the Pedro Miguel Graben. The volcano has an age spanning from more than 850 ka BP to about 340 ka BP. The central portion of the island is formed by the Caldeira Volcano, a central volcano that has been active since before 440 ka BP. The ages of the basaltic fissure systems are less well constrained. The Horta Platform Fissure System, on the southeast sector of the island, has been active since more then 11 ka BP and its most recent activity is older than 6 ka BP. The Capelo Peninsula Fissure System, forming the west portion of the island, is a geomorphologically young region. This system has been active until the present and produced two historical eruptions, one in AD 1672–1673 and another in AD 1957–1958. © 2015 by the Arizona Board of Regents on behalf of the University of Arizona.