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30 November 2022
Another glimpse of sand on the beach at Esterillos Oeste, Costa Rica… This time, I offer you a trace of an organism moving through the wet sediment: Note the two parallel lines of tracks laid down by little feet, and the central groove that overprints them. It reminded me very much of this similar arrangement, from near St. Andrews in Scotland, but: (1) this is the underside of a bed …
15 July 2018
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
A solo hike in search of anticlines yields new outcrops and good views!
17 January 2018
Here’s a puzzler to warm up your chilly brain this Wednesday morning: Click to enlarge Figure out the story told by this set of imprints in the snow. The branch of science called ichnology studies the traces organisms leave behind. There’s a neat little story here. If you’ve got a guess, then you can check your answer by watching the video that this screenshot came from. It was posted on …
9 March 2017
Who dwells beneath the sands of Islay? Lugworms do. These embedded annelids process the sediment for food, extruding the undigested sand in charismatic piles that adorn the beach of Loch Gruinart.
8 December 2016
Two very different samples tell stories that are full of holes. What’s going on with this weathered sandstone? What’s going on with this fossil scallop shell?
3 October 2016
Rathlin Island lies north of mainland Northern Ireland, a few miles offshore. I spent three lovely days there this past summer, investigating the geology and appreciating the wildlife (puffins and other sea birds, and seals). The geology is pretty straightforward: Paleogene basalt overlying Cretaceous “chalk” (really not so chalky here – technically, it’s the Ulster White Limestone). Here’s a suite of interactive imagery that you can use to explore Rathlin’s …
31 August 2016
In Cape Town for the International Geological Congress, Callan hikes up Table Mountain and finds some superb primary sedimentary structures in sands and shales of the Graafwater Formation.
4 July 2016
Walking along the shore east from St. Andrews, Scotland, along the seaside sandstones of Kinkell Braes, you encounter several extraordinary examples of geology. It’s a great place for the next stop on our Grand Tour of the geology of the British Isles. Here’s the scene: The first stop is a giant eurypterid trackway, potentially the largest invertebrate trackway in the world (Whyte, 2005), on the underside of an overhanging sandstone …
29 June 2016
Check out this sandstone cobble I saw at Barns Ness – it comes bearing gorgeous trace fossils. Can you spot them? Lens cap for scale in all these photos. The next three are close ups of the burrows from the previous image: Plus two more, from other cobbles I encountered::
28 June 2016
Thanks to the website ScottishGeology.com, run by Angus Miller, I learned of Barns Ness, a Mississippian-aged limestone fossil site on the shore not far from where we are staying at Dunbar. We ventured out there on Saturday afternoon, in search of fossils. The presence of the Dunbar Cemenet Works nearby is an indication that this is the most extensive limestone outcrop in central Scotland. I set my field assistant loose …
23 June 2016
We arrived at Old Bushmills at 4:06pm, and the last tour of the distillery for the day had left at 4:00. But all was not lost – We were delighted to see that the visitor center area was paved in slabs of shale with tremendously large, well-preserved trace fossils – sinuous burrows parallel to the bedding plane, in some cases cross-cutting or looping back over themselves! Great stuff – balm …
16 May 2016
Over the weekend, my wife and I took a walk with our son at the Storybrook Trail, an accessible trail with a fine overlook to the east over the Page Valley. There, the Massanutten Sandstone shows a bunch of big beefy trace fossils at this site: both bedding-parallel (Arthophycus-like) and bedding-perpendicular (Skolithos-like) traces. Here’s Bax on a photogenic slab of the quartz arenite, showing the inch-wide bioturbation: A short distance …
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.
23 December 2015
It’s been a week and a half since Mountain Beltway has seen any publishing action, given the overlapping timesucks of the AGU Fall Meeting and the end of the semester. But now I’m back in the Appalachian mountain belt, and my grades are all in, and I have time to think about indulgences like blogging again. Let me make up for it now with a suite of four new macro …
26 October 2015
Another gem from Saturday’s Historical Geology field trip: the bottom of a fine sandstone bed in the Devonian Brallier Formation, showing a variety of primary sedimentary structures, including tool marks, trace fossils, and several flute casts. Current flow direction here would have been from upper left toward lower right. Here’s a version of the photo with a few of these features highlighted:
5 October 2015
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 …
6 April 2015
Recently, I posted about an excellent road cut in Fort Valley showing well-developed 10 cm+ Zoophycos trace fossils. Presented here are three new GigaPan images (two outcrop; one macro) of Zoophycos from the Devonian-aged Mahantango Formation: [gigapan id=”170978″] link [gigapan id=”170977″] link [gigapan id=”170875″] link These images are part of a new “virtual field trip” that I organized to supplement my historical geology field trip to examine the geologic history …
19 March 2015
A morning’s field trip yields an outcrop of excellent Zoophycos trace fossils in southern Fort Valley, Virginia.
6 May 2013
Last week, I mentioned some geologizing with the family in the Staunton area. The furthest west we ventured was to the road connecting Deerfield, Virginia, with West Augusta. There, the Brallier Formation is well exposed in a dramatic roadcut. Explore it for yourself in this M.A.G.I.C. GigaPan: [gigapan id=”128612″] link The Brallier is turbidites, shed off the Acadian Orogeny during the Devonian, kind of like Martinsburg Formation is turbidites shed …