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29 January 2019
The Parallel Roads of Glen Roy
What can we learn from Scotland’s Parallel Roads of Glen Roy?
24 November 2016
U-turn
Scotland was glaciated during the Pleistocene “Ice Ages:” The signatures of glaciation are manifold in a scene like this. Most prominent and easily recognizable is the broad, relatively flat-bottomed U-shaped valley. Now check this one out: That’s a U-turn in a U-shaped valley: the valley is first gouged to the right, then turning around and heading in almost the reverse direction: Good things these things flow so slow, otherwise that …
2 June 2016
Flood deposits of Glacial Lake Missoula outburst floods
Two weeks ago, I went on an awesome, informal field trip to eastern Washington State to visit the Channeled Scablands for the first time. My collegue Bill Richards of North Idaho College picked me up in Spokane and drove me halfway across Washington and back to Moscow, Idaho, over the course of a day. This is a region of the country where a glacier-dammed valley filled up with water (Glacial …
1 June 2016
Varves along Hawk Creek, Washington
Heading into the Columbia River Plateau, Callan and his colleague Bill Richards make a detour in search of some varves from Glacial Lake Columbia. They find them, a credit to the authors of “Washington Rocks!” – the new book from Mountain Press.
26 May 2016
Glaciotectonic thrust at Waubonsee Community College
Glaciers can cause thrust faults! Explore an example from a trench south of Chicago.
12 August 2015
Student guest post: the Belt Supergroup in Glacier National Park
As longtime readers know, late summer is when my Rockies students submit their final projects – web-based explanations of key geologic sites they examined during the trip. Today, I offer you a guest blog post by student John Leaming. You’ll notice that I’m not *completely* absent from the post, however – I make a couple of cameos as “sense of scale.” Enjoy, -CB ______________________________________________________________ Glacier National Park, Belt Supergroup I …
28 October 2014
Glacial striations
Today, I thought I would share some images of lovely “textbook” glacial striations from rocks I saw in the Canadian Rockies this summer…
23 August 2014
An examination of the Horseshoe Canyon Formation in eastern Alberta
An expert on the deltaic depositional setting of eastern Alberta’s Horseshoe Canyon Formation shares field evidence and expertise with Callan’s students.
27 March 2014
Aden Crater
That’s Aden Crater, a Pleistocene shield volcano in southern New Mexico. Here’s what it looks like from above (Google Maps view): I also noted the position of two nearby maar craters: Kilbourne and Hunt Holes. When you climb up to the edge of Aden and look in, you see the congealed and fractured remnants of a lava lake that once filled this to the brim (and indeed, spilled over the …
23 January 2013
Western Inyo gravel strata
This image is from the canyon in which route 168 ascends the Inyo Range from Big Pine, California. View is to the south/southwest. Those are gravel layers that dip gently westward. I think they’re associated with the underlying Waucobi Lake Beds, which are Plio-Pleistocene in age. The lake beds are made of finer stuff, but I think these gravels could be alluvial fan/delta complexes that prograded out into the lake. …
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.