Article Volume 14, Number 8 6 August 2013 doi: 10.1002/ggge.20143 ISSN: 1525-2027 A rootless rockies—Support and lithospheric structure of the Colorado Rocky Mountains inferred from CREST and TA seismic data Steven M. Hansen and Ken G. Dueker Department of Geology and Geophysics, University of Wyoming, Laramie, Wyoming, USA Now at Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Boulder, Colorado, USA (
[email protected]) Josh C. Stachnik Earth and Environmental Sciences Department, Lehigh University, Bethlehem, Pennsylvania,USA Richard C. Aster Geophysical Research Center and Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA Karl E. Karlstrom Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico, USA [1] Support for the Colorado high topography is resolved using seismic data from the Colorado Rocky Mountain (CRM) Experiment and Seismic Transects. The average crustal thickness, derived from P wave receiver function imaging, is 48 km. However, a negative correlation between Moho depth and elevation is observed, which negates Airy-Heiskanen isostasy. Shallow Moho (<45 km depth) is found beneath some of the highest elevations, and therefore, the CRM are rootless. Deep Moho (45–51 km) regions indicate structure inherited from the Proterozoic assembly of the continent. Shear wave velocities from surface wave tomography are mapped to density employing empirical velocity-to-density relations in the crust and mantle temperature modeling. Predicted elastic plate flexure and gravity fields derived from the density model agree with observed long-wavelength topography and Bouguer gravity.