Near-vertical and wide-angle seismic reflection studies of the Moho and sub-crustal lithosphere in NW Canada ...

• Main Author: Oueity, Jounada
• Format: Text
• Language: English
• Published: University of British Columbia 2010
• Subjects: Northwest Territories; Canada
• Online Access: https://dx.doi.org/10.14288/1.0052966; https://doi.library.ubc.ca/10.14288/1.0052966

High quality, coincident near-vertical incidence (NVI) and refraction/wide-angle seismic reflection data (R/WAR) acquired along a profile in the Northwest Territories are used to study the nature of the Moho and subcrustal reflectors. First, we re-examine distinct subhorizontal reflections on NVI data in the uppermost mantle that were interpreted previously as a separate feature from a relict subducted slab. Using forward and inverse traveltime modeling of both data sets along the crooked line, we investigate the origin of the reflections. Our results demonstrate that the subhorizontal reflectors are the continuation of the relict subducted slab, which extends laterally for 300 km at depths from 35 to 90 km. Its base is the source of the R/WAR reflections. The apparent flattening is an artifact of projecting a 3-D geometry onto a 2-D cross section. The shallowly subducted slab probably contributed to the thickening and stabilization of the sub-crustal lithosphere in the region. Second, we examine the ...