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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 …
30 August 2016
Northwest Highlands unconformities (3 of 3): Sub-Ardvreck
It’s time to cover the third and final unconformity I observed this summer in the North-West Highlands of Scotland: the unconformity between the Neoproterozoic Torridonian Group below and the Cambrian Ardvreck Group above. Where I saw it, south of Loch Assynt on the mountain called Beinn Garbh (north of Canisp), it actually is displayed alongside the sub-Torridonian unconformity. The mountain hosts a “double unconformity”! Here is a view, looking south: …
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 October 2015
Bedding/cleavage GigaPans at Harpers Ferry, WV
I’ve been thinking lately about Harpers Ferry, the spot where West Virginia, Virginia, and Maryland meet, at the confluence of the Potomac River and the Shenandoah River. I’ve noted small outcrops of its overturned beddding here previously, and also described a book I read about the man who made the place infamous: John Brown. I went out there again last week with my NOVA colleague Beth Doyle, and we explored …
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 …
3 March 2015
Ichnofossils in Gog quartzite
At the Spiral Tunnels overlook on the Trans-Canada Highway, you can look at trains. Or, you can check out some lovely trace fossils in boulders which divide the viewing area from the highway: These are in the Gog Formation, a Cambrian-aged quartz arenite, mostly fused to quartzite nowadays… I know which subject I would choose to spend my time looking at…
31 December 2014
Tril-o-bits-and-pieces in a boulder on the Athabasca Glacier moraine
I love moraines, rocky beaches, gravel bars – they are like a giant smorgasbord of delicious goodies. Here, for instance, are some close-ups of a trilobite-bearing boulder on the south lateral moraine of the Athasbasca Glacier, Jasper National Park, Alberta. And what are these things? Any ideas?
30 December 2014
Skolithos in Gog quartzite, on the trail to Helen Lake
Some boulders seen on the trail to Helen Lake sported lovely sets of Skolithos trace fossils. Here are two boulders, with the perspective on the tubular paleo-vertical Skolithos burrows being “map view”: Another boulder, in the middle of the trail, showed them in a fine cross-sectional view: (click to enlarge substantially) It also included some interesting “ribbed” vertical traces that I didn’t recognize as familiar: …Diplocraterion, perhaps? Seems too “linear” …
29 December 2014
Intense bioturbation in limy mudrock on the trail to Helen Lake
Look at this! A whole boulder made of trace fossils. Three photos, each more progressively zoomed in than the last. Update: The @ichnologist identifies these as perhaps Thalassinoides.
26 December 2014
Friday fold: another gem from the Chancellor Slate
That pretty much speaks for itself, I reckon.
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.