Sierra Negra and Cerro Azul Volcanoes make up the southern end of Isabela Island in the Galapagos Archipelago. Preliminary observations suggest that these volcanoes are also fundamentally different, with Cerro Azul's lavas being the most primitive and Alcedo's strongly bimodal. Detailed field studies supplemented by geochronology will establish the eruptive history of the volcanoes. Geochemical and petrologic study will be used to determine the petrologic processes responsible for the diversity at the two volcanoes. These data will add further insight into the volcanic and petrologic evolution of Galapagos volcanoes and oceanic volcanism in general.
