Evolution of the Galapagos Hotspot

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

Kurz EAR-0126097 This project will involve a combined geochemical, isotopic, and chronological study of Galapagos lava flows in order to constrain the origin of the Galapagos hotspot and to compare it to other oceanic hotspots, such as Hawaii. An important obstacle to evaluating the temporal evolution of Galapagos volcanoes has been the lack of an eruption time scale. This project will rely heavily on the relatively new dating method of surface exposure dating (using cosmic-ray-produced nuclides such as 3He and 36Cl) to determine lava flow ages. Combining the new age information with the geochemical data (i.e. the isotopes of strontium, neodymium, lead and helium) will help determine if the large geochemical differences between Galapagos volcanoes are related to temporal or spatial variability, which is crucial to hotspot models. One key goal of the research will be to evaluate temporal evolution at Cerro Azul and Fernandina, the two most active volcanoes in the western end archipelago which are thought to be near the center of the present-day hotspot. The project will also generate a west-to-east geochemical transect from Fernandina to San Cristobal to evaluate the hotspot model in the paradigm of plate tectonics. New field work will provide a geochemical comparison of these results to the northern volcanoes on Pinta and Marchena which are presently difficult to explain in standard hotspot models.