This is a collaborative proposal between the Lamont-Doherty Earth Observatory and Yale's Department of Geology and Geophysics to study the seismic structure of lithosphere at the continent-ocean transition in northeastern North America. Our aim is to understand the structure of the lithosphere across this Mezozoic-age passive continental margin, and the pattern of asthenosphic flow under it and around the edge of the craton.

Previous work indicates the presence of several important structures in the mantle on the continental side of the margin: 1) two-layers of distinct mantle fabric, with the upper layer possibly indicating strain in the lithosphere and the lower one flow in the asthenosphere; 2) low shear-velocity streaks that appear to cut across the margin, possibly related to hot spot tracks; and 3) a sub-horizontal interface at about 280 km depth, possibly related to the cratonic keel. A key part of our proposal is to understand how these structures change eastward across the margin into the region of much younger (and possibly simpler) oceanic lithophere of the western Atlantic.

A new synoptic teleseismic dataset (including body wave traveltimes, shear wave splitting measurements, body wave mode-conversion and surface wave dispersion) will be collected with an onshore/offshore array of about 100 seismometers, stretching along a corridor between the Great Lakes and Bermuda. The array will be formed by combining a new 2-year deployment of 10 portable broadband seismic stations and a 15 month deployment of 16 ocean bottom seismometers with existing land stations (including the new Canadian Polaris array).