Last September, at the location of the faulted moraine (eastern Sierra Nevada, California), I took some photos of some of the sexier plutonic contacts exposed in big boulders (erratics) of the glacial till composing the moraine. Check them out. What do you see here?
On last May’s GSW spring field trip to Chain Bridge Flats, I saw a quartz vein: Surely, upon looking at this photograph, you will be struck by the way the vein is not the same thickness along its length, and parts of it appear to be a white line transitioning into a parallelogram, and back … Read more
Whilst discussing how to quantify strain with my GMU structural geology students recently, I hit upon a cool analogy. In order for you to understand the analogy (assuming you’re not a structural geologist), I’ll have to review some background information first. Stick with it, and I promise you a salamander at the end. Structural geologists … Read more
Check out these cool structures in one of the amphibolite bodies exposed along the Billy Goat Trail (C&O Canal NHP, near Potomac, Maryland): Those are shear bands — basically small shear zones that are discretely localized within a larger body of less-deformed rock. Note the grain-size reduction visible in the shear bands, their dextral sense … Read more
My cat loves to sit on, or lie on, paper. Maps are here favorite, but she will take a pile of structural geology labs instead, if that’s all that’s available.
Continuing with the recounting of geological sights in the Owens Valley, California, area… This one is in the Pine Creek area. Take a look at this photo: No, that’s not just a portrait of Jeff Lee and his awesome handlebar mustache. Look behind Jeff, on the hillside above. See the little step down that the … Read more
Back at NOVA Geoblog, I spent a portion of September and October 2009 reviewing the geological wonders I witnessed as part of a GSA field forum in the Owens Valley of California. However, I got distracted by other things, and never finished the series. I’d like to pick up on that today, looking at a … Read more
Intersection of 16th Street and Columbia Road NW… … a wee bit underexposed, eh? Guess the high albedo blew out my iPhone camera. (glove for scale)