Callan shows off a new hallway display in his building at Northern Virginia Community College, showcasing the numerous geologic provinces of northern Virginia (as well as adjacent mid-Atlantic states).
Yesterday afternoon, I spent some time in the field with a colleague, a student, and a gigapan. I took four gigapan images, which are of varying quality due to the partly cloudy day, but still you ought to find them interesting to explore. You can see any of them full-screen by clicking on the word … 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
Spotted this one a week ago today, when I was out exploring north of the Rocky Islands with my GMU Structural Geology students…
Background geology of the Sugarloaf Mountain area. (March 2010) Primary structures in the meta-sandstone of the Sugarloaf Mountain Quartzite. (yesterday) Background on tension gashes. (August 2010)
You’ll recall that I detailed a trip to Sugarloaf on this blog back in March of last year. Well, on Saturday (March of this year), Lily and I returned to this distinctive knob of quartzite for a five-mile hike. Along the way, we saw plenty of metamorphosed quartz sandstone (now quartzite), which was similar to … Read more
Okay, a final post (for now, anyhow) sharing some images from last Friday’s field trip to the Billy Goat Trail, in Potomac, Maryland. Yesterday we looked at lamprophyre dikes, but there are other dikes on the Billy Goat Trail, too. Like this granite pegmatite: What’s interesting to me about this is that the joint set … Read more
Lamprophyre dikes on the Billy Goat Trail (Potomac, Maryland): are they offset because of a fault? Or not? Inquiring minds want to know!
I took my structural geology students out the Billy Goat Trail (upstream half of the “A” loop, near Potomac, Maryland) last Friday, and had them gather data for a project to assess whether or not Mather Gorge is controlled by a fault. I got this idea from Aaron Martin, the structural geologist at the University … Read more