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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 …


10 April 2018

An outcrop showcasing a strand of the Kentucky River Fault System

Roadcuts in Kentucky show Ordovician limestones of two distinct types, replete with fossils and primary sedimentary structures, and juxtaposed by a fault, one strand in the Kentucky River Fault System.


9 April 2018

Orthocone nautiloids of the Lexington Limestone

I took a trip last week to Kentucky. My colleague Kent Ratajeski from the University of Kentucky took me out on a nice all-day field trip to examine some of the local geology. I was particularly impressed with the large straight nautiloid fossils that abounded in the Ordovician-aged Lexington Limestone. Here are a series of photos I took of these orthocones, all on pavement exposures (horizontal bedding planes) with my …


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!


27 March 2017

Cleaved, boudinaged, folded Edinburg Formation southwest of Lexington

Explore a dozen photos highlighting the structural geology of an outcrop of limestone and shale near Lexington, Virginia. Cleavage refraction, overturned beds, boudinage, folds, and even a small fossil – we’ve got something for everyone. Bring the whole family!


15 March 2016


Join Callan for a virtual field trip, as he shares dozens of photos from a recent ‘field review’ of a new geological map in Virginia’s Valley & Ridge province. Highlights: graptolites, trace fossils, geopetal structures, folds and faults.


7 October 2015

The New Market / Lincolnshire contact

Yesterday, I put a photo up here on the blog, and asked you to figure out where the formational contact was in that image. Here’s the image I showed you: It turns out that my plan to have readers upload their copies of the image didn’t work as well as I had planned – apparently you all don’t have as complete a suite of control options as I do. Shocker! …


5 October 2015

Trace fossils in the Juniata and Tuscarora Formations

Route 33 in Pendleton County, West Virginia cuts across the lower Paleozoic stratigraphic section. I went there this past spring on a sedimentology and stratigraphy field trip with the GMU sed/strat class. The trip was orchestrated by professor Rick Diecchio. Here are some scenes from two of the stops – the upper Ordovician Juniata formation (red sandstones and shale intepreted as Taconian molasse) and the overlying Silurian Tuscarora Formation (thick …


12 September 2015

New GigaPans from Team M.A.G.I.C.

Hampshire Formation outcrops on Corridor H, West Virginia: [gigapan id=”178008″] link (Marissa Dudek) [gigapan id=”177198″] link (Callan Bentley) Faults in the Tonoloway Formation, Corridor H, West Virginia: [gigapan id=”176602″] link (Marissa Dudek) Conococheague Formation, showing stromatolites and cross-bedding: [gigapan id=”177155″] link (Callan Bentley) [gigapan id=”177355″] link (Jeffrey Rollins) Tiny folds and faults, from a sample I collected somewhere, sometime… oh well, it’s cool regardless: [gigapan id=”178807″] link (Robin Rohrback) Fern …


30 April 2013

Strained metaconglomerate in Klingle Valley, DC

Following on yesterday’s post about the kink bands within the strained metagraywacke of the Laurel Formation in DC, let’s take the opportunity today to go to Klingle Valley, site of a different facies within the Laurel Formation: a strained metaconglomerate. Though the exposure isn’t as great as the Purgatory Conglomerate, I think you’ll find plenty to hold your attention in these rocks. Close looks will reveal sericite-after-staurolite pseudomorphs (evidence of …


29 April 2013

Kink bands in highly strained Laurel Formation, Rock Creek Shear Zone, DC

Last week before GSW, I spent several pollen-choked hours in Rock Creek Park, GigaPanning some of the rocks of the Rock Creek Shear Zone. Here are some exposures in the bed of Broad Branch that show lovely kink banding. In at least one spot, you can see a conjugate pair, so these rocks were (1) sheared out in a ductile shear zone, producing the foliation, and then (2) compressed under …


21 April 2013

Sleeping Inn with the Martinsburg Formation

Three new GigaPans I shot last Friday east of Staunton, Virginia, at a semi-legendary exposure behind the Sleep Inn at the 250 / 81 intersection. [gigapan id=”127959″] link [gigapan id=”127962″] link [gigapan id=”127961″] link Students: Which way is up? Which criteria did you use to make that determination?


2 April 2013

GigaPan suite from the South Page Valley Martinsburg Outcrop

Are you into structure? Sedimentology? Stratigraphy? Well, I’ve got some good news for you – I’ve imaged several key outcrops on the newly-discovered (to me) roadcut on South Page Valley Road, showcasing the middle Martinsburg Formation turbidites (and their Alleghanian structural overprint). [gigapan id=”126510″] link [gigapan id=”126514″] link [gigapan id=”126509″] link [gigapan id=”126483″] link [gigapan id=”126482″] link [gigapan id=”126475″] link See if you can find: an anticline a syncline a …


20 March 2013

Upper Martinsburg “Cub Sandstone” in GigaPan

Today, two GigaPans shot of the uppermost Martinsburg Formation, informally known as the “Cub Sandstone” since it crops out along Cub Run in the southern part of the Massanutten range. 10 or 15 meters upsection (west) of these two outcrops is the base of the Silurian-aged Massanutten Sandstone, the ridge-forming unit. Lower in the section: [gigapan id=”125617″] link Higher in the section: [gigapan id=”125616″] link If you explore these GigaPans, …


15 March 2013

Friday fold: a recumbent anticline in an abandoned quarry

Yesterday, I spent a pleasant day in the field with John Singleton, the new structural geology professor at George Mason University. I was showing John a couple of sites I’ve used as field trip locations for the GMU structural geology class, and John was showing a couple of new sites to me – places he visited on last fall’s Virginia Geological Field Conference. I missed VGFC last fall, as I …


2 January 2013

Upturned Paleozoic strata on Highway 16, Bighorns, Wyoming

Here’s a terrific outcrop to start off the new year at Mountain Beltway. We’re back in the Bighorns of Wyoming here, on highway 16, traversing the southern portion of the range en route from Buffalo to South Pass City. Click to enlarge Annotated, expanded, and Easter-egg-embedded: Click to enlarge From a different perspective (uphill a tad, looking north), consider this GigaPan I shot at the time: [gigapan id=”83585″] link The …


18 November 2012

Another batch of GigaPans from the M.A.G.I.C. project

My students Alan Pitts, Chris Johnson, Robin Rohrback and I have been busy adding to the Mid-Atlantic Geo-Image Collection. Check out a few of these new GigaPan images: [gigapan id=”118645″] link [gigapan id=”115600″] link [gigapan id=”118644″] link [gigapan id=”115165″] link [gigapan id=”114737″] link [gigapan id=”118648″] link [gigapan id=”114939″] link


3 August 2012

Friday fold: lower Martinsburg Formation near Bixler’s Ferry

The Friday fold is presented in photo, annotated photo, and GigaPan formats. It’s a cleaved anticline in lower Martinsburg Formation limy slate from Page County, Virginia. See if you can spot Mr. E. coli in the GigaPan!


26 May 2011

Tumbling Run: New Market/Lincolnshire contact

Here’s a gigapan I shot yesterday, looking north at the contact between the New Market and Lincolnshire Formations at the classic “Tumbling Run” outcrop south of Strasburg, Virginia: [gigapan id=”78234″] See if you can find the E. coli plush toy I included, or the cm-scale pencil! As usual, you can see it full screen, by clicking on the word “Gigapan” in the lower right.