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27 November 2017

Visiting the K/Pg boundary at Bottaccione Gorge, near Gubbio, Italy

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.

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14 July 2017

Friday fold: chevrons in the Scaglia Rossa, Apennines

The Friday fold visits the Apennine Range of central Italy.

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23 June 2017

Friday fold: Canoeing the Célé River, France

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 banks. This low-amplitude fold is highlighted with the “horizontal” reference line of the river’s edge. …

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16 June 2017

Friday fold: toothpasty Tomstown

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 a tour of Crystal Grottoes, a commercial cave south of Boonsboro. I was impressed at …

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3 October 2016

A virtual field trip to Rathlin Island, Northern Ireland

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 …

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22 July 2016

Friday fold: The walls of Scalloway Castle

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 world. But that need not concern us today. Today we are here for the folds! …

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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 …

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9 June 2016

Storm deposits in Tonoloway Fm. limestone – a virtual sample

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 both primary sedimentary structures like graded bedding and cavity fills (both geopetal indicators), but also …

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8 June 2016

Differential weathering in dolostone – a virtual sample

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 Marissa Dudek Differential weathering (i.e., different rates of weathering for different substances subject to the …

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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 …

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