Structural Deformation of the South-eastern Margin of CA Basin

Elisabeth Bjerkebæk

Orogenesis phases, spanning from Late Early Devonian to Early Carboniferous, most likely affected an extensive area along the margins of the CA Basin. Seismic mapping offshore Banks Island demonstrates the presence and regional extent of a clastic wedge, derived from the exhumed Parry Island Fold Belt, during this period. The clastic wedge was deposited contemporaneous with the orogenesis in a foreland setting, which probably advanced southwestwards through time. Thickness distribution and extensional faults, point towards a phase of a syn-tectonic extension and clastic wedge deposition, coincidental with the Ellesmerian Orogeny (Late Devonian – Early Carboniferous, e.g the Parry Island Fold Belt in the Sverdrup area). This extension could also be a post orogenic extension to the Romanzof deformation (Late Early Devonian – Early Middle Devonian, seen onshore Alaska and northwestern Yukon). The extensional faulting was followed by a comprehensive phase of erosion. The resulting unconformity, which spans from Late Devonian until at least Jurassic times, records an important uplift and erosional event, within the overall geological development of the area. This unconformity and the Paleozoic structures, impart a fundamental control on Mesozoic structuring during rifting, prior to opening of the CA Basin and the later evolution of the passive margin. The Cenozoic time was mainly dominated by thick marine sedimentary deposits, derived from the uplifted hinterland (Canadian Shields), which constitute the largest proportion of the sediments on the oceanic crust in the CA Basin.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013