Great Cranberry Island: Lava Lane

Formative Processes

First a super volcano erupted multiple times leaving layers of alternating lava and ash.  Over time these ancient lava flows were metamorphosed possibly during a mountain building event like that of Appalachia or when the super volcano in the area caldera collapsed. This upturned the volcanic rock from lying horizontal to vertical. 60 million years later the Bakers Island Granite intruded the volcanic rock creating Contact Metamorphosed Siltstone and Slate. The fracture lines going NW-SE and SW-NE cut both rock types; assuming to have occurred after the granite intrusion. The quartz veins tend to follow the fracture orientations, ranging in size from a millimeter to multiple inches across. Weathering is a factor on the coastlines with active seas and strong winds. The volcanic rock is softer and more prone to erosion and sediment build up allowing vegetation to form. Both rock types break along fracture lines and points of cleavage, creating a very angled coast with large to small boulders rounded by wave action. The Cranberry Isles comprise of three different rock types two of which are visible at this field site.