Volume 17, Number 4 (1990)
Articles

Dynamics of the tectonic assembly of northeast Laurentia in geon 18 (1.9-1.8 Ga)

Paul F. Hoffman
Continental Geoscience Division, Geological Survey of Canada, Ottawa, Ontario.
Published December 12, 1990
How to Cite
Hoffman, P. F. (1990). Dynamics of the tectonic assembly of northeast Laurentia in geon 18 (1.9-1.8 Ga). Geoscience Canada, 17(4). Retrieved from https://journals.lib.unb.ca/index.php/GC/article/view/3692

Abstract

A tectonic model is proposed, based on the Cenozoic evolution of Southeast Asia, in which the southeast arm of the Rae Province rotated clockwise in response to collisional indentation of the Superior Province. A dextral pull-apart basin characterized by mafic sill-sediment complexes formed along the leading edge of the rotating block. Relics of this basin, analogous to the Andaman Sea basin of Southeast Asia, were subsequently thrust onto the Superior Province margin where they occur as allocations in the Labrador Trough. A wedge-shaped ancestral Baffin basin, analogous to the South China Sea, opened simultaneously in the wake of the rotating block.The margins of this basin are delineated by the Foxe-Rinkian and Dorset fold belts; their convergence and disappearance westward reflect the primary shape of the basin. North-west-dipping subduction beneath the mouth of the basin accommodated convergence of the Burwell and Nain provinces from the southeast and gave rise to the Cumberland batholith. Docking of the Burwell and Nain provinces caused compressional collapse of the ancestral Baffin basin and sinistral transpression of the Torngat Orogen, respectively. The model is well constrained by existing U-Pb geochronological data and makes predictions which can be tested by additional data.