



Photographer: Mark Koleszar

Summary Author: Mark Koleszar

The above photo shows an interesting example of intersecting iron-rich late Jurassic (or early Cretaceous) granitic intrusions or crosscut dikes. It was taken at Iron Point, Twin Islands in the northern Georgia Strait of British Columbia, Canada. The narrower intrusion (bottom center) would have formed first, filling a previously existing fault line. It was then displaced by a new fault line that was filled with a larger granitic intrusion. Contact melting features can be observed around the edges of the intrusions. Photo taken July 26, 2014.

Photo Details: Camera Model: Nikon D7000; Lens: 17-70mm; Focal Length: 22mm; Aperture: f/11.0; Exposure Time: 0.008s (1/125); ISO equiv: 160; Software: Adobe Photoshop CS6 (Windows).