More from Mount Washington, New Hampshire: some folds in the Madison Member of the Littleton Formation (schist) along the auto road near Cragway Springs (just past 5 miles up; see map below):
IMAGE SOURCE
The folds are asymmetrical, with long west-dipping limbs, and shorter east-dipping limbs.
Happy Friday!
According to my research, a sub-horizontal sheeted joint set seen in the migmatized Src on Mt. Clay is not seen (at least statistically) in the folded, bedded Dl on the side of Mt. Washington. Looking at your photos, I wonder if the reduction in overburden during exhumation caused failure preferentially along bedding planes. It’s clear that there are fractures along the folded S(sub 0), but these fractures curve with the folds. This irregularity may be the reason a nice parallel set matching that in the Src was not found in Dl…
Really great folds eh! I’d imagine the length of the limbs is affected by the direction of thrust – Avalon rammed Gander and Laurentia from the east. Wish I could draw a cartoon here, or maybe I’ll just stick to nice simple brittle deformation!