Seismic reflection trace synthesized from Proterozoic outcrop and its correlation to seismic profiles in northwestern Canada

Abstract

Geological descriptions of the Proterozoic Dismal Lakes and Hornby Bay Group strata northeast of Great Bear Lake in Canada's Northwest Territories were used to compute a synthetic seismic reflection trace that was then correlated with reflection data recorded in the Colville Hills region to the west. Reflectivity of the synthetic trace shows a striking similarity to reflections on the recorded profiles at travel times appropriate for the stratigraphic level of the Dismal Lakes and Hornby Bay groups. The similarity suggests that the method of synthesizing traces from outcrop information can be a valuable tool in areas where well control or other direct ties are lacking. Calibration of the Colville Hills seismic profiles with the synthetic trace indicates that the reflections are best interpreted in terms of the observed regional stratigraphy and, along with geometries observed on more structurally complex reflection profiles immediately west of the Colville Hills, affirms an interpretation of Proterozoic layer-parallel thrust faulting in the area. From this information it follows that a deep detachment may occur near the top of the Hornby Bay Group, in either the Kaertok or Lady Nye formations and that the autochthonous basement (probably 1.8–2.0 Ga Hudsonian) is situated about 1.0–1.5 s (about 3.0–4.5 km) beneath the lowest observed detachment in the Colville Hills region.