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9 September 2016
Friday folds: A study in contrasts at the Walls Boundary Fault, Shetland
A virtual field trip to the Walls Boundary Fault in Shetland reveals an embarrassment of Friday fold riches.
3 September 2016
Viewing the Sea Point migmatite through the lens of GigaPan
It was five years ago when I first visited Sea Point, the outcrop on the coast of the Cape Peninsula where the Cape Granite (~540 Ma) intrudes the (meta-)sedimentary rocks of the Malmesbury Group. The outcrop is (a) beautiful and evocative, and (b) of historical importance, as Charles Darwin visited it while on the voyage of the Beagle, contemplating and confirming Lyell’s assertions of the validity of plutonism as he …
1 September 2016
Archean microbial mats in the news and in GigaPan
The news yesterday of 3.7 Ga stromatolites in Greenland prompts a closer look at 3.22 Ga microbially-induced sedimentary structures in the Barberton Greenstone Belt’s Moodies group sandstones.
16 August 2016
Northwest Highlands unconformities (1 of 3): Sub-Stoer Group
First in a series profiling the three unconformities to be found in the North-West Highlands of Scotland. Today: the sub-Stoer unconformity as exposed at Clachtoll. Explore a Proterozoic buried topography topped with coarse, angular breccia.
2 August 2016
Oldest fossils in the UK: M.I.S.S. in Stoer Group, Scotland
This is the Split Rock at Clachtoll, on the shore of the North-West Highlands of Scotland. You’re looking out to sea, over the Minch. It’s the site that graces the cover of the excellent book A Geological Excursion Guide to the North-West Highlands of Scotland, by Kathryn Goodenough and Marten Krabbendam. “Clach toll” apparently means “Split rock” — Go figure. The Split Rock is an easy landmark to steer toward …
11 July 2016
Kilometer to millimeter: 4 GigaPans to zoom in on Lewisian gneiss
I’m in the North-West Highlands of Scotland, enjoying spectacular geology and less-than-spectacular weather. I’ve been fairly productive on the GigaPan front, regardless, nipping outdoors when the weather permits to shoot outcrops and landscapes. One set I’m particularly pleased with is this suite of four images. They show the Archean-aged Lewisian gneiss, the oldest rock unit in the North-West Highlands, as exposed on a beachside outcrop east of Durness, Sutherland. The …
7 July 2016
Tombolo at St. Ninian’s Isle, Shetland
I came to Shetland for the rocks – but I’ve been surprised and delighted by the huge range of interesting coastal geomorphology to be seen here too. I’ve never seen so many sea stacks, wave-cut cliffs, and bayhead bars in my life. One that is so “classic,” so “textbook” that I couldn’t resist it, is the tombolo that connects St. Ninian’s Isle to mainland Shetland. In Google maps, it couldn’t …
4 July 2016
Virtual field trip to Kinkell Braes, Scotland
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 …
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 …
25 June 2016
A virtual field trip to the Giant’s Causeway, Northern Ireland
Some of planet Earth’s best examples of basaltic cooling columns are found at the Giant’s Causeway in Northern Ireland. In this post, explore four different kinds of interactive digital media as a way of experiencing the Causeway virtually, from the comfort of your computer.
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.