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28 June 2016
“Dunbar marble” at Barns Ness, Scotland
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 …
27 June 2016
Small faults in upper Old Red Sandstone, Dunbar, Scotland
Dunbar, Scotland, is a nice little seaside town that also happens to be the birthplace of the conservationist John Muir. My family and I have been based out of here this week on our European geological GigaPan expedition. But on our first morning, upon visiting Siccar Point (which is nearby), I threw out my back, and spent most of the next two days recuperating. I did manage a short walk …
20 June 2016
Cushendun Conglomerate of the Cross Slieve Group, Northern Ireland
Want a geological irony? Here’s one! You’re looking at a rounded boulder of Cushendun Conglomerate, a Devonian “Old Red Sandstone” unit (Cross Slieve Group) exposed at Cushendun Caves, Northern Ireland, U.K. The irony lies in the repetition of history – a tumbling environment of high water energy, rounding cobbles and boulders and depositing them, in order to make the conglomerate. And now, ~400 million years later, history repeats itself, with …
26 May 2016
Glaciotectonic thrust at Waubonsee Community College
Glaciers can cause thrust faults! Explore an example from a trench south of Chicago.
7 April 2016
New GIGAmacro images of rock samples
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 the western Sierra Nevada of California: Link Araucaria mirabilis gymnosperm cone fossil, from the Cerro …
15 March 2016
Timberville
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.
12 March 2016
3 scenes from the Timberville VA quad field review
Explore a series of spherical photos taken on a field review of a new geologic map in western Virginia.
4 February 2016
The Highlands Controversy, by David Oldroyd
While I’ve spent quality time in Ireland on previous trips, I’ve never been to Scotland. To me, it is terra incognita, and I am eager to explore it this summer. It was with delight then, that I delved into David Oldroyd’s The Highlands Controversy, which at once tickled many parts of my brain: the structural geology part, the history of geology part, and the part that gets giddy with anticipation …
28 December 2015
Corona Heights Fault, San Francisco
At the end of the AGU Fall meeting, Callan visits the Corona Heights “mirror” fault, renowned for its gorgeous slickensides. Explore the site in photos in GigaPans.
12 September 2015
New GigaPans from Team M.A.G.I.C.
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 (Robin Rohrback) Fern fossil in Llewellyn Formation, St. Clair, Pennsylvania: link (Robin Rohrback) Cross-bedding in …
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.