Geochronology of Galápagos seamounts

Abstract

Lavas from seamounts of the central Galápagos 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 Galápagos 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 Galápagos Platform are young (<1 Ma), with the youngest measured ages closest to the platform.