A reprocessing program to enhance the correlation between the surface geology and the seismic data has been completed for seismic line 9 (eastern 100 km) and line 10 in the central region of the Trans-Hudson Orogen of Saskatchewan, Canada. The new seismic images through lateral continuity of reflectivity provide sufficient detail to resolve the discrepancy between the low-dipping, layer-parallel and dextral-reverse nature of the Sturgeon-Weir shear zone (line 9) observed in the field and its steeply dipping (apparent) normal displacement character interpreted on the basis of the initial processing. Furthermore, the new interpretation provides a strong confirmation of the role of Pelican Thrust as a major detachment zone - the main 'sole thrust' - along which juvenile allochthons have been carried across the Archaean microcontinental block. The images are also refined enough to suggest: 1) a boundary within the Pelican Thrust between its internal and external suites; 2) a possible boundary separating a lower (older?) Archaean basement from its upper (younger?) counterpart; and 3) sub-Moho events (M2) which reveal possible involvement of the upper mantle in the collisional tectonic process in addition to the well defined Moho (M1) which probably represents the youngest of the post-collisional detachments.
ASJC Scopus subject areas
- Earth-Surface Processes