Origin of Differentiated Volcanic and Plutonic Rocks from Ascension Island, South Atlantic Ocean

Abstract

altered pre-existing volcanic basement may have been melted or The first phase of felsic magmatism on Ascension Island, in the assimilated during differentiation of some of the felsic magmas. form of trachyte and rhyolite domes, coule es, lava flows, and pyroclastic deposits, created the central and eastern parts of the island between about 10 and 056 my ago. The geochemical characteristics of the felsic rocks are largely consistent with an origin by fractional crystallization of high Zr/Nb mafic magmas as