This project is a follow up to a series of previous CD funded Rocky Mountain focused projects building on the discovery of a low velocity anomaly in the mantle beneath central Colorado. The proposed project involves a wide variety of techniques assembled to address the cause of the so called "Aspen anomaly", its history, and its effect on crustal evolution. The PIs are interested in the connection between changes in the mantle causing modification of surface topography. They have observed that the Aspen anomaly is located beneath the highest portion of the Rocky Mountains. They equate low mantle seismic velocities with low mantle densities to cause uplift. They will investigate whether the very large velocity variations in the mantle beneath this area are: a) in the lithosphere or asthenosphere, b) reflect Proterozoic lithospheric sutures reactivated by Cenozoic tectonism, c) are caused by a plume, and d) are caused by the presence of melt. These are all important and relevant questions for Continental Dynamics.
Specifically, the PIs will use: - passive seismology to better define the anomaly using tomography, receiver functions, surface waves, and anisotrophy; - geological studies (magmatic history, low temperature thermochronology, tectonic geomorphology) to identify Cenozoic tectonic and magmatic history to define long term and current history; - geodynamical models of topography uplift and mantle processes to study their connection.
