folds

Friday Fold: Mist Mountain Formation in Canmore, Alberta

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Let’s journey to the Cretaceous today, to see sandstones, shales, and even some coal strata that have been folded during the eastward thrusting that built the Canadian Rockies. Here’s the same fold, in context, shot in GigaPan on a different day, from a different angle. Can you match it up? link Ben Gadd showed me … Read more

Friday folds from the Shenandoah River

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My student Josh B. found this beautiful map view of a plunging fold in the bed of the Shenandoah River, as viewed in Google Earth: Josh posted his results on Facebook, and then the other Josh (Joshua Villalobos of El Paso Community College) poked around the area and found some others downstream (north): Here’s a … Read more

Friday fold: GSW fall field trip

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Last Saturday was the Geological Society of Washington’s fall field trip. Dan Doctor, Alan Pitts, and I led a team of ~20 geologists out to the great new exposures along Corridor H in West Virginia. Here’s the team in front of some of the parasitic anticlines and synclines that decorate the larger structure of the … Read more

Friday fold: Three more from the Chancellor Slate

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Remember our examination of buckle folding versus passive folding in the Chancellor Slate (cleaved limy mudrock) of eastern British Columbia? Well, here’s another example: There’s so much awesomeness going on in that image, it’s hard to know where to start. The prominent black thin layers are buckled in a very boxy, asymmetric way. In places, … Read more

Friday fold: passively folded marble

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It’s Friday! Here’s Baxter, last Friday, in Athens, Greece. He’s checking out some folds in the marble that’s everywhere in that city: This is a lovely example of passive folding, where all the rock layers being folded have about the same viscosity (low viscosity contrast between layers). No buckling, as a result… Enjoy the weekend, … Read more

Friday fold: Miette Group anticline in Banff National Park, Alberta

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Here’s an outcrop of Miette Group slate, seen at the intersection of the Icefields Parkway with the Trans-Canada Highway, just north of Lake Louise, Alberta: There’s a lovely anticline just to the right of Zack, who obligingly provided a sense of scale. Also note how cleavage which is subparallel to bedding on the far left … Read more

Friday fold: Quartz vein in Catoctin Formation, Point of Rocks, Maryland

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I took this image in 2005, when I was working up a geologic history of the C&O Canal National Historical Park. It’s a vein of quartz, gracefully folded within the Catoctin Formation. The exposure is along the railroad tracks at Point of Rocks, Maryland, easternmost extent of the Blue Ridge province on the north shore … Read more

Friday fold: Contorted Rome Formation next to the Max Meadows Fault

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My student Mercer Parker shot this one over to me the other day: Click to enlarge Those are the slim strata of the Rome Formation (a.k.a. Shady*), strongly deformed in the region adjacent to the Max Meadows (“M&M”?) Fault. Thanks, Mercer! _____________________________________________ * Will the real slim Shady please stand up?

Friday fold: Warspite Anticline

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A final guest Friday fold from reader Howard Allen, who I’m pleased to be meeting up with in Banff late next week… Howard writes the following in describing this lovely scene: Warspite Anticline, Peter Lougheed Provincial Park, Alberta. Photo is a telephoto shot (hence the strong blue alpine haze–the colour cast is an accurate rendition … Read more