DEVELOPMENT OF THE SUPERIOR PROVINCE OF NORTHWESTERN ONTARIO BY MERGING ISLAND ARCS.

Abstract

The major geologic features of Archaean rocks in northeastern Ontario are similar to those of younger rocks in the Cordillera of Western Canada. Thus, in correspondence with an island-arc model proposed for the Cordillera, it is proposed that the Uchi, Wabigoon, and Wawa belts originated as island arcs, which, as they developed, moved northward against the Berens River and Gods Lake craton. Deep basins between the arcs filled with sediments and produced the Quetico and English River belts. Such an origin suggests that the Archaean was not drastically different from succeeding eras and that continental plates, although smaller, were not markedly thinner. Although models proposed on the scanty evidence now available must be regarded as speculative, the evidence does suggest that the comparison of orogens of different ages provides useful controls on such speculations.