Geochronology of Galápagos seamounts

Lavas from seamounts of the central Galapagos Platform and the Carnegie Ridge increase in age with distance from the western edge of the platform, consistent with a hotspot model for the generation of these features. The areal distribution of seamount ages suggests that the pattern of dispersed volcanism seen on the present islands also prevailed between 5 and 6 Ma. Age-distance relationships are consistent with a decrease in the velocity of the Nazca plate relative to the Galapagos hotspot during the past 9 m.y., most likely at ∼5 Ma when there was a change in Pacific-hotspot motion. Alternatively, the plate velocity remained constant and volcanism at a single seamount endured up to 7 m.y. Lavas from seamounts along the Wolf-Darwin lineament to the northwest of the Galapagos Platform are young (<1 Ma), with the youngest measured ages closest to the platform.