Tia Complex migmatitic schist

This high-grade complexly deformed psammo-pelitic schist is from the Tia Metamorphic Complex in the Southern New England Orogen. The metamorphic grade is upper amphibolite facies, with temperatures peaking at around 550°C - hot enough for the rock to develop incipient melt veins. Prior to this at lower temperatures, abundant quartz veins developed. Rocks of the Tia Complex exhibit up to five phases of deformation visible at outcrop or hand specimen scale. Three of these are visible in this specimen as F3, F4 and F5 folds, along with two metamorphic foliations. S3 is the main form surface, and a spaced S5 cleavage is defined by biotite. Early quartz veins are generaly parallel to S3, and later granitic veins are parallel to F5 fold hinges. L5/3 intersection lineations are also visible.