The Grenville Front itself is a zone from 20 to 30 km wide, with increased metamorphic effects in rocks on both the Superior and Grenville sides. The fault varies between a high-angle reverse and a thrust that dips southeast. Elsewhere, the best evidence for the discontinuity comes from abrupt changes in metamorphic grade, with higher intensities in the Grenville Province. Foliation, as well as a number of megafractures, trends northeast. The east-northeast secondary trend noted in the two rose diagrams is associated with the boundary zone between provinces.
Low areas contain glacial fill.
Forests consist of maple and pine in the south that give way to spruce and fir northward. This image is southeast of the previous Landsat images and shows how erosion has differentially etched out the folded metasediments.