High-Mg andesites and related lavas from southwest Puerto Rico (Greater Antilles Island Arc): Petrogenetic links with emplacement of the Late Cretaceous Caribbean mantle plume

Two-pyroxene-bearing high-Mg andesite, hornblende basalt and andesite, and high-Fe augite basalt were erupted simultaneously in southwest Puerto Rico between 85 and 65 Ma. An analogy with geologic settings in Cenozoic arcs indicates that hornblende-bearing lavas and high-Mg andesites, restricted to the southwestern-most corner of Puerto Rico, represent the forearc assemblage, whereas high-Fe basalts, concentrated in an adjacent volcanic belt …