national parks

Guest post: Red Rock Canyon

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A guest post by Callan’s student Jacob Douma Traveling with Callan Bentley and Pete Berquist through the Canadian Rockies on their Regional Geology Field Course in July 2012, we were exposed to a variety of physiographic features. Among them, was Red Rock Canyon located 16 km from Waterton Townsite within Waterton Lakes National Park, Alberta. … Read more

Cottonwood trees being consumed by caterpillars

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In Waterton Lakes National Park, Alberta, my students and I camped under the shade of cottonwood trees… But some of the cottonwoods’ branches were looking a little thin… Caterpillars were munching on their leaves. And some trees had been completely denuded by the voracious little larvae: All three photos are taken on roughly the same … Read more

Tool casts from the Sulphur Mountain Formation of the Spray River Group, Banff

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Yesterday I showed you salt casts; today I’ll share a different kind of cast: the infillings of small scorings in the sediment made by tumbling pebbles or sticks or other “tools,”tumbling down a current. These small gouges were later infilled from above by a younger deposit of sediment (frequently coarser in grain size). You’re looking … Read more

Weekend critters from Shenandoah National Park

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My penchant for macro photographer of small animals continues unabated. Here are some images from Saturday and Sunday along Skyline Drive and the Whiteoak Canyon / Cedar Run loop in Shenandoah National Park, Virginia: A fly with a hairy back of golden iridescence. Compare it to this one: Very similar in some regards, but check … Read more

Visiting the Swift Run

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I took my structural geology students to that fine outcrop of the Swift Run Formation in eastern Shenandoah National Park on Friday. There, we saw lovely primary structures with tectonic fabric overprinting (as I have showcased here previously). Consider this graded bed with subsequent (vertical) cleavage: And here’s the hinge of a nice passive fold, … Read more

Those could be pillows

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More pillow-like structures, seen in the Catoctin Formation, on the west side of the Blue Ridge Parkway about ten miles south of Interstate 64. Mini Sharpie for scale – what do you think? They don’t seem to be as strongly fracture-controlled as the Stony Man area “pillows.” But dang, they sure are small… Read the … Read more

Skolithos in the sun

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Today, I share with you eight images that I took yesterday on Skyline Drive in Shenandoah National Park: Blocks of Antietam Formation quartzite (meta-quartz sandstone) of Cambrian age, used in the low rock walls of an overlook parking pull-out. They all bear lovely Skolithos trace fossils (seen end-on, and in cross-section):

Compton Peak: superb columnar jointing

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After my talk Wednesday night to the Potomac Appalachian Trail Club, I got an email from PATC member Tom Johnson, with an extraordinary photo attached. It shows an exceptional outcrop of the Neoproterozoic Catoctin Formation, exposed atop Compton Peak in northern Shenandoah National Park, Virginia. The outcrop features enormous, well-preserved cooling columns from these ancient … Read more

Friday fold: cleaved slate in Kootenay National Park

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This summer, a week or two after our wedding, my wife and I found ourselves in the Canadian Rockies for a pre-honeymoon. Part of our time was spent on a backpacking trip to Floe Lake in Kootenay National Park, British Columbia. On our hike in, we passed this outcrop of Chancellor Slate, a Cambrian aged … Read more