Age Constraints on the Eruptive History of the Northern Galapagos Volcanic Province

The Northern Galápagos Volcanic Province, located north of the Galápagos Archipelago and centered near the 90° 50'W Galápagos transform fault (GTF), is represented by a complex set of islands, seamount chains and ridges. To better understand the dynamics of ridge-hotspot interaction in this unique region, we collected bathymetry, sidescan sonar, magnetic, sub-bottom seismic, and gravity data during the 2010 FLAMINGO (MV1007) cruise of the R/V Melville. In addition to the geophysical studies, lava samples were recovered by dredge at 43 locations on both the Nazca Plate and Cocos Plate. The bathymetric mapping shows that region on the Nazca Plate west of the GTF is dominated by numerous seamounts aligned in three volcanic lineaments, the largest of which is the Wolf-Darwin Lineament. Faulting patterns and seamount morphology suggest that the locations and orientations of the lineaments may be partly controlled by the lithospheric stress field associated with the GTF. In contrast, east of the GTF on the Cocos Plate, there is little evidence of constructional volcanism - instead, there are several linear, nearly ridge-parallel, faulted features with up to 1km of relief. In this paper, we present new 40Ar/39Ar ages from the lavas collected in this region. These data allow us to constrain the age and duration of volcanism, thereby testing different models for interactions between the Galápagos plume and the Galápagos Spreading Center.