Callan Bentley

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

Friday fold: Spray Mountain Group siltstone

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Today, we return to Banff National Park, to the outcrops next to the parking area for Bow River Falls… Zoomed-in closer to the thinner layers at left: These strata (shale and siltstone) were laid down in the quiet aftermath of the Permo-Triassic extinction, as terranes colliding with the edge of North America (far to the … Read more

Dobsonfly

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Here’s your macrobug of the week: a male dobsonfly we encountered last weekend, while making houseguests some pizza. What a beast! Envelope for scale: Adding a finger (not too close) for scale: A better perspective on the envelope, with a shirt button thrown in too: Lola looks intimidated as she contemplates this insect through the … 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

Salt casts from Purcell (Belt) Supergroup rocks, Waterton National Park

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I’ve previously mentioned the lovely salt casts that can be found in Mesoproterozoic argillites of the Belt (“Purcell” in Canada) Supergroup of the Canadian Rockies (including the North American portion of the Canadian Rockies: Glacier National Park and the Sevier fold and thrust belt immediately south of it). When I led my Rockies field class … Read more

One year

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One year ago today, Lily and I had a fantastic wedding week in Montana. To celebrate the year we’ve been together since then, today I’ve got a gazillion photos to share – reliving the week for those who were there, and sharing it with those who weren’t able to make it… Our first group hike: … Read more

101 Geo-Sites You’ve Gotta See in Google Earth

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Mountain Beltway reader “Earth Mama” responded to the recent geo-meme (which started here, folks!) by compiling all these visit-worthy locations in a single Google Earth KMZ file. If reading the lists from the various geobloggers didn’t whet your appetite, now you’ve got the ‘virtual globe’ option…. Hi Callan, I wanted to thank you for the … Read more

Friday fold: scenes from the trail to Bertha Lake

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Given that I’m leaving tomorrow for the Canadian Rockies, I’ve been inspired to look through some of my photos from last summer, and to realize how few of them I’ve blogged so far. So let me show you some folded things today that Lily and I saw the afternoon we arrived at Waterton Lakes National … Read more

Floe Lake hike

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Last summer, my wife and I spent some time in the Canadian Rockies. One of the things we did was to take a three-day backpacking trip to Floe Lake, in Kootenay National Park, British Columbia. We picked a rough couple of days for hiking – We got a lot of Canadian Rockies precipitation out there: … Read more

Plane views: Powder River Basin and Black Hills

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Happy fourth of July! Here’s two scenes that are emblematic of America, as seen from my airplane window last March flying from Reno to Minneapolis. Here’s the scene in the central Powder River Basin of eastern Wyoming: If you zoom in, you’ll see what caught my eye – regular rectangular excavations into the surface. These … Read more

Granite dikes that have been folded and boudinaged

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It seems like a good morning to return to Ontario, and to the Archean shear zones exposed at the Quetico/Wabigoon subprovince boundary of the Superior Craton. Readers will hopefully recall that I spent several days absorbing structural goodness from these rocks on a field trip before the Minneapolis GSA meeting last fall. The trip was … Read more

Friday fold: Franciscan chert in Golden Gate Park

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This week, the Friday fold comes to us courtesy of fellow AGU-hosted geoblogger Jessica Ball: That’s chert cropping out in Golden Gate Park, San Francisco. Maybe you should check it out in December when you’re in the Bay area for the AGU Fall Meeting? Outcrop location: Lat/Long: 37.771517,-122.4777. Annotated version: Recall there are more chert … Read more