Today, you get a photo from GMU structure student Nik D. This is a small exposure in the Hampshire Formation (Devonian) on New Route 55 in West Virginia. It shows a fine example of plumose structure with the not-often-seen concentric ribs running perpendicular to the ‘plumes.’ At the edge of the joint, you can see … Read more
Can anyone tell me what’s so significant about this stick that the Smithsonian would put it on display?
Yesterday, Lily and I embraced my first day of no-more-classes by taking a hike. We drove out to Massanutten Mountain and hiked up to Signal Knob, a ten-mile (roundtrip) jaunt with about 1500 feet of elevation gain. Along the way, we saw a lot of Massanutten Formation quartz sandstone (Silurian), a few trace fossils, a … Read more
Today’s imagery put me in mind of two hands reaching for one another: What do you think? Shocking coincidence? Or a bit of a stretch?
Ice… serpentine… halite… What do they all have in common? I’ve discussed mineral “ghosts” here before — really, those are only pseudomorphs, where one mineral’s chemistry becomes unstable due to a change in conditions, and then a new mineral forms in the same space. I’ve also brought up the issue of clasts of minerals which … Read more
I took a look at some interesting blobby structures in the Swift Run Formation last week, and walked readers through my logic in tentatively concluding that they were ball & pillow structures (soft sediment deformation), though overprinted by a pervasive (Alleghanian) cleavage. As we move west in the Appalachian mountain belt, the rocks are less … Read more
I have a student this semester, Diane, who is a flight attendant. Every weekend, she’s off to some cool European city with her husband, a pilot. Up until now, she’s been bringing me little gifts of beer from each trip. She drops 60 cents in Germany, and then that week I get to taste a … Read more
A macro shot of a beetle (length ~11 mm) I saw on the wildlife-rich George Mason University structure trip two weekends ago… Neat iridescence, eh? I love macro photography, especially of bugs.
On my structure field trip just over a week ago, we found the contact between the Mesoproterozoic-aged Blue Ridge basement complex and the overlying Neoproterozoic Catoctin flood basalts (now metamorphosed to greenstone). This nonconformity can be found just west of the Appalachian Trail at the Little Stony Man parking area in Shenandoah National Park. Here’s … Read more
For the twenty-fourth edition of the Accretionary Wedge, I selected “heroes” as the theme. For those of you new to the geoblogosphere, the Accretionary Wedge is a ~monthly geoblog “carnival,” wherein various and sundry geobloggers write posts on a common theme. Broadly speaking, submissions to this edition fell into three categories: (1) professional heroes, (2) … Read more