Today’s Friday fold comes to us from Alistair Knock on Flickr*, via Dave Schumaker’s Geology News Blog, where there is a daily Flickr feed of photos tagged with the word “geology”: Bigger version here. The fold in question, an overturned synform, is at a place called “Butt of Lewis” (the northernmost point on the island … Read more
My student Troy was working on the geologic history of the Thoroughfare Gap regions for his Honors project this semester, and we went out there last week to check out some stuff. One thing I was struck by was how much more deformed these rocks were than I had expected. This was particularly evident in … Read more
I already mentioned the “paddle hackle” that I saw on the field trip I took to Thoroughfare Gap in February. Well, this week I went back out to Throughfare Gap twice, once with a student and once with my fianceé and a friend of ours. I saw cool new plumes both times, decorating joint surfaces … Read more
Kink bands in phyllite. Another sample from the GMU teaching collection. Ruler in the background shows blurry mm-scale demarcations. Happy Friday — enjoy your weekend!
This is a sample from the teaching collection at George Mason University: The swirly folds exhibited by this quartz vein reminds me of von Karman vortices. Happy Friday! For me, it’s the last day of classes of the spring semester at NOVA, though GMU is still in session for a couple more weeks. I’m grateful … Read more
Stopped at Sideling Hill, Maryland, a few weeks back with my three Honors students, on our way to Pittsburgh for the northeast/north-central GSA section meeting. Robin took this photo of me with some sandstone beds that reveal two nice examples of joint anatomy, complementary in their structure: First focus in on the area right of … Read more
The Friday fold is a contorted chert sample from Turkey.
The Friday fold is glimpsed from Google Earth. Atop a valley glacier in south-central Alaska’s Kenai mountain range, a fold of “transverse moraine” displays parasitic folds.
Here’s a joint extracted from gelatin during this year’s GMU structural geology “Make a Joint” exercise: A soda bottle full of congealed gelatin serves a “rock.” We then use construction clamps to impart a stress field to the gelatin bottle. Into it, we inject fluid plaster of Paris. The extra pore fluid pressure causes a … Read more
Cretaceous calcarenite layers, folded along the coast of Spain (?). From the repository of geological images hosted by the European Geological Union, Imaggeo. I was reminded of Imaggeo earlier this week, and it’s a great place to go browse around for cool photos of geological things. It could use a better search interface, but oh … Read more