14 March 2018 01:59 in 3D, devonian, GEODE, gigamacro, gigapan, primary structures, sediment, valley and ridge, west virginia by Callan Bentley
Last week, I was in Morgantown, West Virginia, to deliver a colloquium talk to the geology department at West Virginia University of geological visualization. The next day, I took some time on the way home to geologize a bit on the road called Corridor H, a gorgeous transect through the eastern Allegheny Plateau and western Valley & Ridge provinces. I focused that day on the Hampshire Formation, Foreknobs Formation, and …
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13 May 2017 15:21 in mass wasting, valley and ridge, west virginia by Callan Bentley
There’s a section of my favorite road, the lovely nowhere-to-nowhere Corridor H, that seems to be having some issues with slumping. I noted this in November of 2015, and I return to the topic today. Here’s a look at the slope, with old drainage “French drains” installed, and a fresh scarp transecting it just the same: I see at least three small scarps there. A short distance further to the …
30 November 2015 16:19 in mass wasting, west virginia by Callan Bentley
I was out on Corridor H last week, looking at rocks with my Honors student, and on the way back from the field work, I noticed this: Click to enlarge That’s a fresh slump scarp running across a slope that is gradually sliding downhill. (The left half of the image is moving down relative to the right.) To judge from the rip-rap-filled culverts, this slope must have a previously-documented history …
27 October 2015 13:31 in GEODE, gigapan, google earth, gsa, m.a.g.i.c., valley and ridge, west virginia by Callan Bentley
My Historical Geology class was in for a new experience for the semester’s capstone field trip. Before we headed out into the field (to the exceptional roadcuts along Corridor H in Grant and Hardy Counties, West Virginia), we had them examine all the outcrops virtually, in the comfort of the classroom, using digital imagery. I say “we” because this initiative was a collaboration with my colleague Alan Pitts, who developed …
24 November 2014 12:19 in devonian, limestone, structure, stylolites, valley and ridge, west virginia by Callan Bentley
Saturday I posted some images of bedding-parallel stylolites from one member of the Devonian-aged Helderberg Formation (or one formation in the Helderberg Group; I’m not sure whose stratigraphy is preferable in this case). Here we are, further up-section, and you can see both bedding-parallel and non-bedding-parallel stylolites overprinting the limestone: Bedding-parallel stylolites can be understood readily in terms of sedimentary loading (compression from above), but non-bedding-parallel stylolites imply a maximum …
22 November 2014 16:13 in echinoderms, fossils, limestone, structure, stylolites, valley and ridge, west virginia by Callan Bentley
Long week, no blog. But, hey – it’s Saturday, and I have a couple of hours of breathing room – so here are some stylolites in a crinoidal grainstrone in the New Creek member of the Helderberg Formation, exposed on Corridor H in West Virginia. Stylolites are pressure solution features, which overall form perpendicular to the maximum squeezing direction (maximum principal stress direction, σ1), and have little wiggle peaks that …
10 October 2014 12:48 in folds, Friday Fold, GEODE, gigapan, structure, valley and ridge, west virginia by Callan Bentley
Three folded sandstone slab-blobs will serve as today’s Friday folds. Meet the ploudins!
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6 October 2014 12:22 in limestone, silurian, structure, stylolites, valley and ridge, west virginia by Callan Bentley
What can a little squiggle in a rock tell us? Stylolites in West Virginian limestone cut across the bedding plane, implying Alleghanian tectonic stresses.
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2 July 2014 12:18 in devonian, faults, GEODE, gigapan, m.a.g.i.c., structure, valley and ridge, west virginia by Callan Bentley
Here’s a breccia that Dan Doctor and I found in a tabular zone within the Helderberg Group (Devonian limestones) in one of the massive new roadcuts along Corridor H. link Is it a fault breccia or a sedimentary breccia? The breccia was bedding parallel, which suggests it could be just another bed, but it’s so darn coarse and angular (unlike the rest of the Helderberg) that we were skeptical. Indeed, …
4 June 2014 12:09 in faults, limestone, silurian, structure, valley and ridge, west virginia by Callan Bentley
Here’s something fun: Click to enlarge Those strata are Silurian-aged Tonoloway Formation carbonates. There are plenty of dessication cracks to be seen, as well as salt casts, among the layers exposed. But more eye-catching at this distance is the faulting that disrupts the high-contrast layers… Both (apparent) normal and reverse faults can be seen in this road cut. Exciting stuff! We visited it two weeks ago on “Border to Beltway’s” …