Proterozoic deformation beneath Banks Island: implications for the regional extent of the Racklan orogeny

Seismic reflection data from the northeast corner of Banks Island in arctic Canada show that Proterozoic layers were subjected to at least two deformational events prior to the Cambrian. The oldest of these events involved folding and faulting(?) from west-northwest to east-southeast. The ages of the layers that were subjected to this deformation are unknown; however, younger Proterozoic layers, probably correlative with the Shaler Group (ca. 1.1–0.8 Ga), unconformably overlie the folded and faulted layers, and were themselves regionally arched prior to the Cambrian. The relative position of the oldest deformed strata is thus the same as that of the strata observed to the south beneath the Anderson Plains, where thrust faulting and folding deformed pre-Mackenzie Mountains Supergroup (Shaler Group equivalent) layers during at the time of the Racklan orogeny (ca. 1.1–1.2 Ga). Distant effects of the Racklan orogeny may therefore extend to at least the northeast side of Banks Island.