I first mentioned the Waterfall Formation on this blog in May of 2008, but this was my first time visiting it in situ. Previously, including the May 2008 visit, was memorable time with charismatic boulders of float. The occasion to see this geologic unit in outcrop was the field trip 6 days ago with the … Read more
Last Sunday morning, two of my former GMU students, Aaron and Alan, led a hike for the GMU Geo-Club to Thoroughfare Gap, a water gap in the Bull Run Mountains of Virginia’s eastern Blue Ridge province. I’ve mentioned the Weverton Formation structures we saw there, and a nice example of a hackle fringe in previous … Read more
Another serendipitous sighting on last weekend’s field trip to Thoroughfare Gap was this boulder of Weverton Formation, lying in the no-man’s-land between the railroad tracks and Broad Run: As you look at this boulder, I hope you will notice what caught my eye and prompted me to take the photo. There’s a big flat surface … Read more
Callan joins some students from George Mason University on a field trip to the rock exposures at Thoroughfare Gap, Virginia, where meta-sedimentary rocks are exposed in the eastern Blue Ridge province.
The Friday fold takes us to some high-grade metamorphic rocks in the Piedmont of northern Virginia.
I didn’t mention it yesterday, but there was one other structure that I saw at my newest outcrop on New 55. This is it: That’s a bunch of fractures. The broken rock is being altered by preferential fluid flow through the fractures. The fluid is not inert; it’s chemically active, and reacting with the rock. … Read more
Here’s three shots of the Konnarock Formation diamictite, taken with my Nikon microscope. Field of view is about 1 cm in each shot.
More of the new scientific medium* I showed you on Wednesday: animated GIFs of super-small stuff, to give a sense of depth. This time, I included a 1 mm scale bar: These are laminations of silt and clay in the rhythmites of the lower Konnarock Formation. If the above image moves too fast for your … Read more
Another look at Konnarock Formation diamictite, showing colorful reaction “halos” around some clasts.
One other thing that I noticed during my visit last weekend to the Virginia Museum of Natural History in Martinsville, Virginia, was this fold. As soon as I saw it, I squealed “Oooh! That’s going to be the Friday fold!” It says something about the crowd I was traveling with that everyone (a) knew what … Read more
A detailed description of one of the Virginia Blue Ridge’s most intriguing geologic formations: a maroon sedimentary sequence showing the advance of “Snowball Earth” glaciers in the Neoproterozoic.
The author describes a quick visit to the Virginia Museum of Natural History in Martinsville, Virginia, on his way back to DC from Thanksgiving travel. Highlights: a dinosaur, a giant stromatolite, encrusting crinoids (they do that?) and a giant ground sloth.
On Saturday, after a fruitful 24 hours at the VCCS Science Peer Conference, my colleague Pete Berquist (of Thomas Nelson Community College) and I led a field trip to examine the geology of the Richmond, Virginia, area. We were joined by seven of our VCCS science-teaching colleagues and author Lisa Starr, a speaker at the … Read more
Today’s Friday fold comes to us courtesy of Gary Fleming, botanist extraordinaire and brother of Tony Fleming, geological Jack of All Trades. Together, the Fleming brothers led a field trip for the Geological Society of Washington. While I was on that field trip, the topic of polyphase deformation came up, which led a couple of … Read more
For the second year in a row, more exotic travel plans meant that I wasn’t able to attend the superb Virginia Geological Field Conference. I see that they have now posted some photos on the group’s Facebook page, so go check them out to see what we both missed last weekend. Here’s a taste: Sheared … Read more
As mentioned, I spent a significant part of last weekend was spent on a paleomagnetic sampling project with collaborators from the University of Michigan. On Friday, this was our field area: That’s the south slopes of Old Rag Mountain, a popular Blue Ridge hiking destination because unlike many Virginia peaks, when you get to the … Read more
This video was produced by my friend Pete Berquist. It shows rapidly moving “sheets” of sand saltating down Grandview Beach in Hampton, Virginia, during high winds associated with Hurricane Earl. What do you notice here? A couple of things jump out at me, but I’d be curious to hear what this video makes Mountain Beltway … Read more
Here’s a new video from Greg Willis, the same guy who brought us a fine video on Piedmont geology. In this new opus (20 minutes), Greg details the geology of the Massanutten Synclinorium (Shenandoah Valley, Massanutten Mountain, and Fort Valley) in western Virginia. WordPress isn’t letting me embed it here, but you should go and … Read more
Mountain Beltway reader Greg Willis attended my colleague Ken Rasmussen’s Triassic Rift Valley field course last weekend, and sent me this photo of the view inside the Luck Stone diabase quarry in Centreville, Virginia: Here’s an annotated version: Both photos are enlargeable by clicking on them (twice). This quarry chews into rock right along the … Read more
I spent last Thursday on a long field trip in the Valley and Ridge province of northernwestern Virginia. Leading the trip was Dan Doctor of the USGS-Reston. Accompanying Dan was a UVA environmental science student named Nathan. And the NOVA crew rounded it out: professor Ken Rasmussen from the Annandale campus, associate professor Victor Zabielski … Read more