Abstract

Several groups of Aphebian layered rocks in the northeastern Canadian Shield have been correlated because of lithologic and stratigraphic similarities and alignment of groups and structural trends. Most of these layered rocks lie in three distinct fold belts which from south to north have been named the Dorset, Foxe, and the Committee Fold Belts.The widespread occurrence of Aphebian outliers between the fold belts indicates that Aphebian strata probably originally covered the entire area from the Circum–Ungava Geosyncline or Fold Belt east to the Dorset Fold Belt and north to the Committee Fold Belt. The name Baffin Geosyncline is proposed for this depositional zone. Aphebian layered rocks in the two last-named fold belts were probably deposited in marginal mio-eugeosynclinal zones of the main geosyncline and are mainly meta-shale, meta-graywacke, and metamorphosed basic volcanic rocks and associated basic and ultrabasic intrusions. The Aphebian rocks of the Dorset and Foxe Fold Belts were deposited in the central shelf zone of the Baffin Geosyncline and are mainly meta-shale, meta-graywacke, rusty quartz-rich gneiss, marble, and quartzite.The Aphebian layered rocks have been intruded by large granitic plutons and have been metamorphosed to amphibolite and granulite facies of regional metamorphism. Age determinations and structural data indicate that a mid-Aphebian orogeny affected much of the northern part of this region 2000–2200 m.y. ago, and that the whole region was strongly affected by the Hudsonian orogeny.

You do not currently have access to this article.