Callan shares images of extraordinary boudinage outcrops in strained Archean meta-basalts on the Quetico-Wabigoon subprovince boundary within the southern Superior Craton. Ogle these gorgeous structures in awe and wonder.
The Friday fold is a contribution from the Massachusetts Geological Survey. It shows a migmatite with lovely structure. An upcoming (free) field trip to this location will be part of the 2012 Structural Geology and Tectonics Forum: an event readers may be interested in attending
One of Callan’s former students leads a field trip to examine the western edge of the Blue Ridge geologic province, attempting to answer the question of whether the Blue Ridge / Valley & Ridge contact is indeed the trace of a thrust fault. Breccias and S-C fabrics tell part of the story…
After a roadside explanation just an hour and a half earlier on how the relationship between bedding and cleavage can reveal whether bedding is likely right-side-up or up-side-down, my students and I were walking up the road to the Ancient Bristlecone Pine Forest in the White Mountains of California, and I saw this outcrop that … Read more
On Monday, my field course students and I tried to find the Poleta folds, but I had failed to figure out in advance the best access point. Oops. That’s the way the cookie crumbles, when you’ve got big plans but not enough time to enact them with appropriate pre-planning. We had some happy exploration of … Read more
Meter-scale fold in metagraywacke layers at the head of Mather Gorge, Maryland shore of the Potomac River, highlighted by differential weathering along the layering. Annotated interpretation: Happy Friday!
Incipient mylonitization of a granite/granitoid, as displayed in a sample on a shelf of one of the meeting rooms adjacent to the Reading Room of the Geological Sciences building at the University of Texas at El Paso. Same side, slightly different lighting conditions: I’d call this a protomylonite. Some of you might prefer the term … Read more
[gigapan id=”98833″] GigaPan by Alan Pitts, as part of the M.A.G.I.C. project that we are working on. Here’s another one from a few meters away. Here’s a shot from 2.5 minutes after Alan saw this anticline for the first time. Here’s some shots of my own early visit to the site, after I first found … Read more
Today, let’s zoom in on a little something I saw at the outcrop of the Contorted Bed in downtown Johannesburg, South Africa: What are these things? I only saw them at this one spot. These look to me like en echelon fractures at a high angle to bedding, that were then deformed due to dextral … Read more
Callan looks south across the border from Texas. Above the drug-war-ravaged town of Juarez, the Sierra de Juarez Mountains feature an enormous recumbent synform.