Seismic tomography of the Colorado Rocky Mountains upper mantle from CREST: Lithosphere–asthenosphere interactions and mantle support of topography

摘要: Abstract The CREST experiment (Colorado Rocky Mountains Experiment and Seismic Transects) integrated the EarthScope USArray Transportable Array with portable permanent stations to provide detailed seismic imaging of crust mantle properties beneath highest topography region Mountains. Inverting approximately 14,600 P- 3600 S-wave arrival times recorded at 160 for upper V p s structure, we find that large perturbations relative AK135 7% variations 8% take place over very short (approaching tens kilometers) lateral distances. Highest heterogeneity is observed in 300 km mantle, but well resolved low velocity features extend top transition zone portions these images. previously noted Aspen Anomaly into multiple features. lowest velocities are found San Juan Mountains, which clearly distinguished from other northern Rio Grande Rift, Taos/Latir region, below Never Summer We suggest anomaly, a similar feature New Mexico, related delamination remnant heat (and melt) sites extraordinarily voluminous middle-Cenozoic volcanism. interpret northeast–southwest grain structure parallels Colorado Mineral belt depths near 150 as being reflective control by uppermost Proterozoic accretionary lithospheric architecture. Further north west, Wyoming province Plateau show high indicative thick (∼150 km) preserved Archean lithosphere, respectively. Overall, highly heterogeneous southern reflecting interfingered chemical lithosphere has been, currently being, replaced modified upwelling asthenosphere. Low here indicate this process may be sourced deeply 410 km. One driving mechanism interaction between hydration-induced partial melt destabilized downwelling deeper mantle. Tomographic crustal thickness results modeling elevations substantially supported strong correlations thin crust/high across region. This, along rich heterogeneity, suggests buoyancy dynamics central present day topographic support recent geomorphic evolution