9419021 Levander In 1995 the Canadian Lithoprobe program plans a continental scale active source expanding spread seismic profile to probe the Archean upper mantle beneath the Alberta Plains, with the midpoint of the probe over the Medicine Hat Block, a crustal block which has been high standing since the Proterozoic. This DeepProbe profile, centered near Calgary, has a 2500km aperture along the front and interior of the western Cordillera. The Canadians will shoot into 2 dense receiver spreads, each roughly 600km long, extending from Calgary southward into the US to the Colorado-Wyoming border. This project is a component of a suite of 3 integrated US seismic experiments which will complement the Canadian effort, making use of similar experimental methodologies, but addressing different tectonic and geologic problems within the US. The 3 experiments are: 1) an active source expanding spread large- aperture mantle probe; 2) passive teleseismic recording and 3) a crustal refraction profile. The wide-range of scales examined permits geodynamic evaluation of a complete crust-mantle system. The US experiments will investigate Phanerozoic asthenosphere and Archean-Proterozoic lithosphere modified by Phanerozoic tectonism beneath the Colorado Plateau/Southern Rocky Mountains. ***
