Last week, the Friday fold featured a kinked phyllite of unknown provenance that is currently resident in David King Hall 2074 on the campus of George Mason University. However, on Tuesday of last week, I found another kinked phyllite, this one out in the real world, at Thoroughfare Gap, in the Harpers Formation of the … 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
On the original version of this blog, I showed off a couple of pseudoscorpions that I found under a rock in Montana. On Tuesday, poking around at pollen-ific Thoroughfare Gap with my Honors student Troy, I found another one. Looked like the same thing. See for yourself. I shot a bunch of macro shots with … Read more
If I had a structural superpower, it would be to shoot en echelon tension gash arrays from my fingertips: Photo by Sharon Ruggeiri
I shot this gigapan (900 images) last Thursday during the lunch break of the annual “Geology of Virginia” symposium hosted by the Commonwealth of Virginia’s Department of Geology and Mineral Resources. [gigapan id=”75096″] It shows the rock garden outside the DGMR’s offices in Charlottesville, a place where they have collected charismatic megasamples from across the … Read more
Lily and I took a hike yesterday over Old Rag Mountain, a popular destination in Shenandoah National Park. I took the opportunity to shoot a few gigapan images of the scene. If you click on the word “Gigapan” in the lower right of any of these images, it will take you to gigapan.org’s full page … Read more
The Shenandoah Valley of western Virginia records the switch in late Ordovician time from passive margin sedimentation associated with the Sauk and Tippecanoe epeiric seas, to active margin sedimentation associated with the onset of the Taconian Orogeny to the east. Higher up in the stack, a similar pattern is seen: a return to passive margin … Read more
Migmatite schist sample from Orange Springs Farm, near Unionville, Virginia, with cm-demarcated pencil for scale. Sample was cut and polished. Here’s what the untreated sample looks like: [youtube=http://www.youtube.com/watch?v=XDDcLVp_4Ss] Happy Friday. Enjoy your weekend. I’m off to the Northeastern / North-Central joint section meeting of the Geological Society of America today. We’ll see if my time … Read more
Took a hike this morning with my bride-to-be, out to Buzzard Rock on the northeastern corner of Massanutten Mountain. There, we observed numerous boulders of Massanutten Sandstone float, many bearing charismatic cross-beds. Here’s one more slab of float, presumably weathered out along the main bed, showing gorgeous internal cross-stratification: A closer look at the left … Read more
Another fold seen in the Catoctin Formation, where last week we encountered a very different style of folding — chevrons overprinting Catoctin foliation. Here, we instead have a light colored vein that appears to have been buckled into a semi-ptygmatic form. The trace of the foliation in the Catoctin is discernible, too. Enjoy your Friday!