BARSCOPE - EXTENDING EARTHSCOPE BETWEEN THE APPALACHIANS AND THE ROCKIES

As the EarthScope program ends, investigators interested in various regions will likely consider how to build on its results and intellectual momentum. As researchers interested in the evolution of the continental interior, we have begun conceptualizing a program of active and passive source seismic experiments targeting areas where important geologic problems could be addressed by high-resolution crustal studies and other methods. These would be community projects open to all interested university, geological survey, and industry investigators. Projects would be planned by integrating existing geological and geophysical (including EarthScope) data to maximize the chances of answering interesting questions. We envision 100-200 km long refraction-reflection seismic lines to image structure - layering, faults, terrane boundaries, suture zones, etc. - in the crust. Given the advances in reflection seismology, we can expect far better results than were possible in the 1980s COCORP program. The dense profiles would be surrounded by a wider footprint of seismic instruments that would provide broader and deeper - especially Moho - images, and complementary passive seismic studies. An initial project in Kentucky or Ohio could target the "East Continental Mystery Triangle", the poorly understood region west of the Appalachians involving parts of the East Continental Gravity High, the Midcontinent Rift's east arm, the Grenville Front, the Illinois and Appalachian Basins, the Eastern Granite-Rhyolite Province, and other tectonic elements. The results would give important new insight into how Amazonia and other crustal blocks collided with Laurentia as part of the assembly of Rodinia during the Grenville Orogeny (~1.3-0.98 Ga). Other possible study areas will be explored that allow existing large scale results to be more fully utilized in answering open questions on the evolution of the North America plate.