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16 September 2022
Friday fold: isoclinal limestone near Harrisonburg
This weekend, my family and I traveled to a little agrotainment complex north of Harrisonburg, Virginia, a joint called Back Home On The Farm. It featured a corn maze, hayrides, petting zoo, apple cider donuts, and pumpkin picking. All typical fall frolic; good clean fun. But there were also big blocks of limestone everywhere on the property. I did my best to check them all out. I was mainly scanning …
13 November 2020
Friday fold: stairsteps in the Tonoloway
A quick “Friday fold” that is expressed in three dimensions – “stairstep” style folds deforming a bed of Tonoloway Formation dolostone…
7 August 2020
Friday fold: syncline in Helderberg Group limestones
I went on a day of field work last week to Corridor H, West Virginia, to help make drone-based photogrammetric 3D models of the huge outcrops there. One site we stopped at is this beautiful V-shaped syncline in Devonian-aged Helderberg Group limestones. Click to enlarge Here are two layers traced out: Here is a GigaPan that Alan Pitts shot of this outcrop several years ago, when it was a bit …
31 July 2020
Friday fold: Two Mile Run Overlook
I spied an anticline last weekend while engaging in a day of solo geologizing along Skyline Drive in Shenandoah National Park. At Two Mile Run Overlook, I gazed west toward the southern tip of Massanutten Mountain, and noted what appeared to be an anticline in the Blue Ridge foothills: Annotated: And here it is in Google Maps, with the perspective rotated to looking ~along strike to the north, and I …
8 May 2020
Friday fold: Wills Mountain Anticline
Eric Fulmer (who pitched in with last week’s Friday fold) returns this week with another treasure. He writes, I was in Hopeville, WV a couple of years ago. The entire area between Cabins and Hopeville is a real joy (geologically and recreationally) as some of the most resistant rocks of the Mid-Atlantic Appalachians are folded and exposed in quick succession and with great relief. I am particularly fond of seeing …
18 October 2019
Friday folds from the Foreknobs Formation
TGIF! That’s my seven year old field assistant showing off the shape of a syncline in shale, siltstone, and fine sandstone of the Foreknobs Formation, a Devonian nearshore package of clastic sediment in the Valley & Ridge Province of eastern West Virginia. Want to see something freaky for Halloween? Photoshop can make it happen: Ewwww. Creepy! Another shot of the same fold, with a thick massive sand above a thicker …
18 March 2019
New discoveries in the Martinsburg Formation
A virtual field trip to examine some deepwater clastic sediments shed off the first phase of Appalachian mountain building, and deformed in the third phase. It’s a lovely day for a field trip to the late Ordovician!
12 October 2018
Friday fold: the Devil’s Backbone and its neighbor
It’s Friday; time to stretch our backbones out in anticipation of the weekend. Let’s look to a backboney-named Friday fold for a little inspiration… …And what’s that, just down the road? Another fold, in need of a catchy name…
17 August 2018
Friday folds: Moomaw Reservoir outcrops
Break out your paddle and sunhat. We’re going kayaking on Lake Moomaw, in search of Friday folds…
16 August 2018
A suite of deformational features in Lancaster limestones
In the Landisville Quarry, Lancaster, Pennsylvania, there is a quarry that cuts into Cambrian limestones. (The exact identity of these limestones is apparently a matter of some dispute, but that’s not going to stop us!) I visited the quarry in June on a field trip offered through the NAGT’s Eastern Section annual meeting. We witnessed multiple varieties of deformation there. First off, there was straight-up brittle extension, resulting in bedding-perpendicular …
15 July 2018
Chickie’s Rock, Pennsylvania
A virtual field trip to the deformed quartzites and metaconglomerates of Chickie’s Rock and Sam Lewis State Park in Lancaster County, Pennsylvania.
26 March 2018
Raider of the Lost Anticlines
A solo hike in search of anticlines yields new outcrops and good views!
14 March 2018
New media to show off exemplary features of the Devonian-aged Hampshire Formation along Corridor H, West Virginia
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 …
23 January 2018
A kid and his slicks
On a family hike, Callan’s son finds some interesting smooth lines on a rock. What are they? What do they tell us? Tune in for a brief history of Appalachian geology.
29 September 2017
Friday folds: soft sediment deformation in thin sections of MTD sandstone
The Friday folds are small soft-sediment deformational features within a dismembered, folded sandstone (a “ploudin”) from a mass transport deposit from the latest Devonian of West Virginia.
11 August 2017
Friday fold: Eagle Rock
For the Friday fold, Callan digs out images of Eagle Rock, Virginia, well aged in his digital archive for a decade!
16 June 2017
Friday fold: toothpasty Tomstown
I spent last weekend at the National Association of Geoscience Teachers’ Eastern Section meeting, based out of the Community College of Baltimore County in Catonsville, Maryland. One of the two field trips I took headed out to the western Piedmont, Blue Ridge and Valley & Ridge provinces of western Maryland. On that trip, we took a tour of Crystal Grottoes, a commercial cave south of Boonsboro. I was impressed at …
6 June 2017
Loading sags in homogeneous lithologies?
Can soft sediment deformation “loading structures” (ball & pillow) occur when the two strata are identical in composition? Grok on these field photos and chime in with your best hypothesis.
23 May 2017
Silurian tidal flat carbonates of the Tonoloway Formation
Journey to the Silurian period in what is today the Valley & Ridge province of eastern West Virginia to see some exquisite sedimentary rocks that represent deposition in a very arid, very shallow setting.
13 May 2017
Slump palimpsest, Corridor H
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 …
