K-Ar ages from the eastern Azores group (Santa Maria, São Miguel and the Formigas Islands)
1975; Elsevier BV; Volume: 8; Issue: 4 Linguagem: Inglês
10.1016/0024-4937(75)90008-0
ISSN1872-6143
AutoresA.A. Abdel-Monem, L. A. Fernández, Gary M. Boone,
Tópico(s)Geological formations and processes
ResumoPresent estimates of the age of volcanic activity in the eastern Azores group are based on shelly fauna in a coquina zone separating the two basaltic sequences on Santa Maria. A Vindobonian (Middle Miocene) age has been assigned to the coquina zone. Our K-Ar data suggests that it was deposited 4–6 m.y. ago, i.e. Mio-Pliocene in age. The basaltic series exposed below the coquina zone on Santa Maria is 6–8 m.y. old and probably much older. The post-coquina basaltic complex is 4 m.y. old and younger. The Nordeste basaltic complex in the NE part of São Miguel and the basaltic flows of the Formigas Bank are also 4 m.y. old and younger. We suggest that the three latter basaltic sequences are chronostratigraphic equivalents.
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