Bronson Hill Arc

The Bronson Hill Arc is a bimodal volcanic arc and associated sediments that formed over a west dipping subduction zone during the Ordovician period as part of the Taconic Orogeny. These rocks are presently well exposed along the Connecticut River Valley of Vermont and New Hampshire. The arc is evidenced by plutonism and extrusive volcanism, including the Ammonoosuc Volcanics and the overlying Partridge Formation. It is related to the slightly older Shelburne Falls arc that lies to the west. These rocks were metamorphosed and deformed during the Acadian Orogeny and the Alleghenian Orogeny.