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10 November 2011
Shear bands in the Grassy Portage Sill
Continuing now with the discussion of my pre-GSA meeting field trip to examine the structural geology of the Quetico-Wabigoon subprovince boundary within the Superior Craton of southern Ontario, Canada. Our penultimate stop on the second day of the trip was a roadcut exposing the gabbro of the Grassy Portage Sill. This is what it looks like: …Except where it doesn’t. In places, it looks like this, instead: Zooming in a …