Callan Bentley 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
I have many heroes, but the one I would like to pay tribute to today is Larry Wiseman, my mentor through my undergraduate years at William & Mary and beyond. Now, Larry is a biologist, not a geologist — but he probably did more to frame my life’s work than any other individual. At William … Read more
On my structural geology field trip this past weekend, I made one major modification compared to last year’s iteration. I added a fifth detailed “field study area” at an outcrop of the Swift Run Formation, a Neoproterozoic sedimentary unit that is discontinuous in extent between the underlying Blue Ridge basement complex and overlying Catoctin Formation … Read more
… So, today is: … and not only that, it’s the 40th anniversary of the first “Earth Day.” Shall we reflect? Yes, let’s shall. My career as a geoscientist was largely inspired by desire to spend time outside, and that in turn was inspired by a lot of positive outdoor experiences as a child and … Read more
Whilst poking about Sunday on the fine exposures along West Virginia’s new route 55, my structural geology students and I noticed some joint surfaces decorated with pyrolusite dendrites. But I also found a nice slab which had one surface covered with a thicker coat of manganese oxide, and here the habit was botryoidal, like little … Read more
Remember the mud I saw on Pimmit Run? Turns out that West Virginia mud pulls many of the same tricks as Virginia mud. Here’s some mud cracks I noticed on Sunday afternoon on the shoulder of New Route 55 in eastern West Virginia: Notice how West Virginia spices her mudcracks with chunks of Silurian quartzite … Read more
For the first time ever, I have won a Where on Google Earth? that Ron Schott hosted, heavy on the clues. Now that it’s my turn to host, I’d like to spice things up a bit with a dynamic view. Using Google Earth’s historical imagery feature (the little “clock” button up top), I managed to … Read more
While on our structural geology field trip this week, my GMU students and I encountered an eastern worm snake, Carphophis amoenus amoenus. The little charmer at first reminded me of a boa, like the ‘rubber boa’ I once found in California (a real animal, not made of rubber), and then I convinced myself it was … Read more
What do I have in common with luminaries like Mike Fay, James Balog, and Stuart Pimm? We’re all this year’s cadre of Fine Fellows, recipients of free Gigapanning equipment and training (at a conference in Pittsburgh in November) on how to use it. Ron Schott is of course the king of geology Gigapanners, though he … Read more
A few more photos from Pimmit Run … of mud. This mud has lots of interesting features, including dessication cracks showing lovely 120° triple junctions connecting up with their neighbors, raindrop impressions, and animal tracks. Tracks of at least three species here: (Clicking on this one will make it bigger) Mud: not as fascinating as … Read more
Hiking last Sunday in Rock Creek Park, DC, I saw this boulder and my eye was immediately drawn to the linear pattern running from upper left towards lower right (Swiss Army knife at upper right for scale): Because that photo is not especially large, let’s zoom in a bit to two sections… Here is Photo … Read more