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15 April 2022
Friday fold: Cretaceous Canada
A guest contribution for the Friday fold, from reader Christian Gronau: Christian reports that this is located on the North side of Hwy.11, 20 miles east of Saskatchewan River Crossing, Alberta. Eastern foothills of the Canadian Rocky Mountains. Faulting and folding in Early Cretaceous Luscar Group sediments. Typical repeating sequence of sandstone, siltstone and coal. Thanks for pitching in, Christian! Happy Friday to all!
15 May 2020
Friday fold: Argentinian turbidites
Zoltán Sylvester brings us this Friday’s fold: And there’s more where that came from: These are deepwater strata of the Lower Cretaceous Rio Mayer Formation, exposed near Lago Argentino, Argentina, south of the lake’s northwest “arm,” about here. They were deformed so exquisitely during Andean mountain-building. Zoltán is a talented photographer, and you should check out more of his work here.
25 April 2019
How We Got To Now, by Steven Johnson
I was very impressed with Steven Johnson’s The Invention of Air when I read it last summer. So recently, I decided to sample another of his books, this one a six-part microhistory about innovations that altered the course of human history. The six are: 1) cleanliness/hygiene (specifically in medicine and drinking water), 2) measurement of time, 3) glass (think lenses!), 4) understanding of light, 5) refrigeration, and 6) the recording …
8 March 2019
Friday fold: Dent de Morcles
The Friday fold is a recumbent anticline/syncline pair, deforming the K/Pg boundary in the Swiss Alps, as photographed from the air by Bernhard Edmaier.
25 June 2018
Mafic volcanics atop felsic instrusives: Sonora Pass, California
Sonora Pass, California, is a lovely place to examine a volcanic-on-plutonic nonconformity that spans about 80 million years of missing time. Let’s check it out on a photo-rich virtual field trip!
24 April 2018
T. rex and the Crater of Doom, by Walter Alvarez
Walter Alvarez has a new book out, and its publication reminded me that though I read and appreciated The Mountains of St. Francis, I had never read his most famous work — the account of how he and his father and a team of other researchers zeroed in on an extraterrestrial impact explanation for the end-Cretaceous extinction. So last week I read T. rex and the Crater of Doom (1997). …
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.
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 …
27 March 2016
Another trio of 3D models
Here are three more of my Photoscan-generated, Sketchfab-hosted 3D models of rock samples: Mud cracks in Tonoloway Formation tidal flat carbonates, Corridor H, West Virginia: Diorite from the eastern Sierra Nevada of California: Vein cross-cutting foliated & lineated gneiss, Blue Ridge basement complex, Virginia:
20 March 2016
3D and GIGAmacro views of Cerro Toro conglomerate
Six years ago, I went to Patagonia*, and collected this sample there. It’s a deep-water conglomerate from the Cerro Toro Formation. I’ve imaged it here in two media: the Sketchfab-hosted (Photoscan-generated) 3D model, and GigaPan-hosted (GIGAmacro-generated) views of both the front and the back. In combination, these three digital items can probably give you a pretty good sense of the sample: Link Link _______________________ * In case you missed it …
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.