April 27, 2010
The photo above shows an attention-getting pegmatite dike near Essex, Connecticut. Pegmatites are igneous deposits that commonly contain large crystals and rather uncommon minerals. Numerous dikes can be found intruding into the metamorphic rock mass that took shape during the compression phase of the ancient Pangaea supercontinent's formation. After the breakup of Pangaea, approximately 200 million years ago, there were a number of episodes of igneous intrusions into the metamorphic mass. Today, all along the Route 9 North highway many repeating diagonal dikes are clearly visible. Photo taken on April 5, 2010.
Photo details: Camera: NIKON E5900; Image Date: 2010:04:05 13:10:12; Focal Length: 7.8mm (35mm equivalent: 38mm); Aperture: f/4.8; Exposure Time: 0.0027 s (1/374); ISO equiv: 64