6 November 2013

Natural Bridge, Yoho National Park: Bedding/cleavage relationships

Posted by Callan Bentley

Check out the scene at Natural Bridge in Yoho National Park, British Columbia, Canada:


Don’t confuse this “Natural Bridge” with the one in Virginia. Here, in the western Canadian Rockies, the structural geology is much better. You may recall that I’ve previously featured outcrops from nearby this site as a Friday fold.

It’s a great place for examining bedding / cleavage relationships in the rocks. Here’s the previous picture, annotated:


…It’s a broad synform, with a cleavage fan.

Another scene, close by, in the same rocks:

DSC01685 DSC01685anno

…Same thing!

Another nice well-developed expression of cleavage overprinting bedding:



Here’s a bed that has begun to buckle (note the small wrinkles with axes perpendicular to compression), but not yet cleaved so nicely as the strata in the previous pictures:


Finally, a conjugate pair of faults disrupting bedding in a nearby outcrop (also only very lightly cleaved):



I’m looking forward to returning to this site next summer on my Canadian Rockies field course. We are accepting applications now, if you’re interested in joining us. Know any great students who would benefit from this trip? Please pass the information on to them!