Darrel Cowan of the University of Washington has pitched in a Friday fold. Check this lovely scene out: Darrel says this is a recumbent fold in the Upper Triassic Nizina and Chitistone limestones. I took the photo when I worked for Shell in 1973 or 1974. I’m pretty sure it is on the west wall … Read more
As noted previously, the old way of viewing gigapixel imagery is no more. But there is a new, better way. The GIGAmacro company has a better viewing platform that can be used either with images uploaded to their server or with pre-existing images that currently “live” at GigaPan.com. Here’s an example: a roadcut of limestone … Read more
Some scaly Italian limestone shows off two foliations (S and C) which reveal the kinematic motions that built the Apennines.
This image graces the cover of the new report, Challenges and opportunities for research in tectonics: Understanding deformation and the processes that link Earth systems, from geologic time to human time. A community vision document submitted to the U.S. National Science Foundation: Make it bigger by clicking it The photo is of a landscape in … Read more
A trip to one of the most famous outcrops in the world, a place with a stratum that marked a profound shift in the state of the planet, and a profound shift in geologic thinking. Plus, for the author, it’s a romantic journey back in time.
The Friday fold visits the Apennine Range of central Italy.
I was in southern France last week, exploring an awesome suite of caves cut into the Causses limestone plateau. My family and I took an afternoon to paddle a canoe down 5 kilometers of the Célé River. While floating along, we spied a gentle, open fold in the limestone layers that crop out along the … Read more
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 … Read more
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 … Read more
When in Shetland, one of my first stops was the museum in Scalloway, and one of the ancillary benefits of visiting there is the castle next door: Scalloway Castle includes building stones derived from the local limestone – a Neoproterozoic unit that has recently been chemostratigraphically correlated with Snowball Earth cap carbonates elsewhere in the … Read more
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 … Read more
Our series of virtual samples continues! This week, I’m presenting examples of a visualization combination that leverages the advantages of the GIGAmacro system with the 3D ‘virtual sample’ perspective of the Sketchfab-hosted model: the same sample presented in both formats. Today, we feature a lovely slab of limestone, chock full of fossil material, and showing … Read more
Our series of virtual samples continues! This week, I’m presenting examples of a visualization combination that leverages the advantages of the GIGAmacro system with the 3D ‘virtual sample’ perspective of the Sketchfab-hosted model: the same sample presented in both formats. Today, we feature a differentially weathered dolostone. Link GIGAmacro by Callan Bentley Photoscan model by … Read more
Another week, another batch of new images produced on my home-based Magnify2 imaging system from GIGAmacro. Leptaena brachiopod in (Mississippian?) limestone from Montana: Link Here’s the flip side of the same sample, with a lot of fenestrate bryozoans to see: Link Fault breccia from the Corona Heights Fault of San Francisco: Link Amygdular metabasalt from … Read more
Check this out: It’s a sample of the Reynolds Limestone, a member of the Mississippian-aged Mauch Chunk Formation, chock full of gastropod fossils. The image here is a 3D model made with Agisoft PhotoScan, a 3D model rendering program. The only input was a series of ~32 photos taken of the sample at various angles … Read more
When snail shells are deposited in a bunch of sediment, they serve as tiny architectural elements, with a “roof” that protects their interiors. Any sediment mixed into the shell’s interior will settle out (more or less horizontally), and then there will be empty space (filled with water, probably) above that. As burial proceeds and diagenesis … Read more
What geological stories can be read from the stone on the front of a building? Walking past some facing stone in Baltimore, Callan discovers a wealth of little clues.
Hampshire Formation outcrops on Corridor H, West Virginia: link (Marissa Dudek) link (Callan Bentley) Faults in the Tonoloway Formation, Corridor H, West Virginia: link (Marissa Dudek) Conococheague Formation, showing stromatolites and cross-bedding: link (Callan Bentley) link (Jeffrey Rollins) Tiny folds and faults, from a sample I collected somewhere, sometime… oh well, it’s cool regardless: link … Read more
Ladies and gentlemen, I give you… The Friday fold: This beauty came to my attention on Monday, when I was lucky enough to go on a field trip with my friends Leigh and Mary. They are founding members of our local informal geology club, and we have been meaning to take a Cedar Creek field … Read more
What is Matt looking at here? Matt was one of my Rockies students this summer, a geology major at the University of Virginia. Together with another UVA student and students from Mary Washington University and George Mason University, Matt embarked on a mountain-climbing hike during our evening camping at Swift Dam, near Depuyer, Montana. The … Read more