The Kinematic Evolution of the Galapagos Triple Junction

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

Researchers from the Woods Hole Oceanographic Institution are analyzing of multibeam bathymetry data that were recently collected at the Galapagos triple junction. The overarching goals are to understand: 1) whether the stresses associated with the large propagating Cocos-Nazca Rift near the East Pacific Rise controls the location and stability of transient rifting to its north and south; 2) the conditions that favored the formation of the Galapagos microplate about 1 million years ago. The research team will: 1) compile all existing raw multibeam data and integrate them with the recently collected raw data; 2) analyze topographic patterns south of the Cocos-Nazca Rift, before the initiation of the Galapagos microplate, to assess the applicability of the crack interaction model; 3) decipher the controls on the initiation of Dietz Deep Rift, the nearly concurrent formation of a large volcano near the East Pacific Rise, and the establishment of the Galapagos microplate; 4) understand topographic patterns within the microplate. A ridge-ridge-ridge oceanic triple junction is where three mid-ocean spreading centers meet. Seafloor topography at ridge-ridge-ridge oceanic triple junctions indicates that the major lithosphere plates in this setting are deforming internally. The observed deformation is not well understood, but can provide important information on how the lithosphere plates that cover Earth?s surface respond to stresses. The recently surveyed Galapagos triple junction region, provides an unparalleled view of an oceanic triple junction, and presents the opportunity to address several outstanding questions about the response of the lithosphere to stresses in this setting where the major plates meet and their boundaries are rapidly changing. This project addresses the outstanding large-scale problem of how major lithospheric plates deform under stress and how plate boundaries develop. The study of the Galapagos triple junction region may also provide insight into how magma rising beneath the plates and erupting on the surface might change the lithospheric stresses. In addition, the initiation and growth of the Galapagos microplate at this region has important implications for the dynamics of mid-ocean ridges.