While at the Vulcan Quarry in Manassas, Virginia, a few weeks ago, the principle interesting feature I saw on the individual blocks of rock we sorted through was slickensides. I saw dozens and dozens of examples, in both the hornfels and the diabase, but here are five nice examples to share: No sense of scale … Read more
When I was flying back from Phase I of “Border to Beltway” in Texas this past March, I was delighted to photograph a bunch of local geology from the air, including this prominent diabase quarry in Manassas: I had never been to this particular quarry before, but as it turned out, it was one of … Read more
Here’s a little scene along Route 340 / 522, north of Front Royal and south of Double Tollgate, Virginia, in the Shenandoah Valley: The rock here is limestone and shale of the Edinburg Formation, a late Ordovician unit that records the transition from passive margin sedimentation to the increasingly ‘dirty’ clastic influence of the Taconian … Read more
I thought this was pretty cool. Remember the blog post a year ago wherein I documented a slump on a hillside on the campus of James Madison University in Harrisonburg, Virginia, adjacent to Interstate 81? Well, a student at JMU, Dan Rowson, ended up doing his research on that slump, and it turned out that … Read more
A sure sign of the advent of spring in Fort Valley is the blooming of the shadblow, an understory tree species with clusters of white flowers: My wife and I took our son for a hike yesterday, and the shadblow was pretty much the only tree with anything on its branches: I infer that shadblow … Read more
I recently read God’s Harvard, by Washington Post reporter Hanna Rosin. It’s a profile of the people and philosophy behind Patrick Henry College, a private Christian college located not too far from me, in Purcellville, Virginia. PHC is an Evangelical place that strives to serve its homeschooled matriculating freshmen with a sense of worldliness and … Read more
We visited the Philip Carter Winery this weekend with family. Baxter and I were pleased to see outcrops of charnockite scattered over the property (located in the middle of the Blue Ridge geologic province). As any 18-month-old will tell you, charnockite is a pyroxene-bearing granitoid. It’s a distinctive and common rock type in Virginia’s Proterozoic … Read more
This past week, there’s been a beautiful sight along the stretch of the Fort Valley Road that goes past the Blue Hole section of Passage Creek. Click to enlarge Ice has been forming beautiful forms as groundwater seeps out along bedding planes in the Massanutten Sandstone (a Silurian-aged quartz arenite, folded during late Paleozoic Alleghanian … Read more
One of the intriguing rocks you find in Virginia, at the interface between the Valley and Ridge province and the Blue Ridge province, is distinctive brecciated Antietam Formation. The Antietam (sometimes known as the “Erwin,” especially in Shenandoah National Park), is a quartz arenite (quartz sandstone) that has been variably fused to quartzite in some … Read more
I was first alerted to the proposal of a new bill in the Virginia House of Delegates last Wednesday by a colleague at James Madison University, Eric Pyle. Eric and I serve as state Councilors for the state of Virginia in the National Association of Geoscience Teachers. As such, we are sincerely concerned about any … Read more
Here’s our birding yard list (species seen in/from our yard) for the past year. You can compare it with 2012’s list here. Canada geese Goldfinch Tufted titmouse Dark-eyed junco Mourning dove Black-capped chickadee White-breasted nuthatch Downy woodpecker Hairy woodpecker Blue jay Brown creeper American crow Red-bellied woodpecker Pileated woodpecker Red-shouldered hawk Carolina wren Turkey vulture … Read more
Last month, I led a fun new tour for the Smithsonian Associates: an all-day tour of the geology of Virginia wine country. Wine-making is a bigger-and-bigger business in Virginia these days, and I’ve been exploring it on and off over the past few years, ever since participating on a wine-themed geology field trip through the … Read more
I got word yesterday that the fisher, a medium-sized mustelid (Like a marten, an animal that I’ve seen once up in the Adirondacks of New York), has begun re-colonizing wild parts of Virginia. This is pretty exciting news – a friend from high school shared the image below with me: That’s from a wildlife camera … Read more
As soon as I got back from GSA, I had to run two field trips, back to back. Both are the same trip: my Historical Geology field trip to the Massanutten Synclinorium. Here’s yesterday’s crew perched on a moderately-dipping slab of Massanutten Sandstone along Passage Creek: Today, it’s the same routine all over again, though … Read more
I have two new GigaPans of hand samples to share with you this morning… The Edinburg Formation graptolites from Mint Spring, Virginia, that I featured here back in May, can now be explored in GIGAmacro hand sample: link Students: are these colonial or solitary organisms? Benthic, nektonic, or planktonic? Does this relate to their usefulness … Read more
One thing that’s 100% worth doing if you find yourself visiting Natural Bridge, Virginia, is to pop in for a visit at Foamhenge, an art installation a few miles away. Foamhenge is a full-scale replica of Stonehenge, made of styrofoam (covered in gray latex paint). It’s a few years old now, so it’s begun to … Read more
Lily and I took our son to the Virginia Scottish Games on Sunday. This is an annual competition of events in traditionally Scottish feats – throwing heavy things, mainly. There is also fried food, whisky, and some terrific music. The event is held at the Great Meadow, south of The Plains, Virginia. I had never … Read more
Our three-day karst theme wraps up today with a visit to Natural Bridge, Virginia, an impressive sight: I went to Natural Bridge early last week to give a talk to a group of Road Scholars (an Elderhostel-like program) about the Snowball Earth. Part of my compensation for the talk was a night’s lodging at the … Read more
To continue with the karst theme I initiated yesterday, let me share a few photos today from a visit last week to Luray Caverns, a large show cave in Page County, Virginia near the town of Luray. This was my first visit to Luray Caverns since I was a child. Probably it had been thirty … Read more
Take a look at this… Doesn’t look like much, does it? But it’s actually the surface expression of a vast, long-lived sinkhole. If you walk over to the hole and look in, you can’t see the bottom. It’s semi-supported by limestone boulders, but between the boulders, the soil and gravel filter down, down, down, like … Read more