Friday Fold

Friday fold: isoclinal flow structures in Icelandic lava

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While soaking at some fine outdoor hot springs in southern Iceland (near Höfn) last week, I spied a Friday fold on the rock wall above the hot pots: Iceland is not a place where we would expect to find ductile folds in already-lithified rocks, so I’m guessing that these are folds related to flow in … Read more

Friday fold: Mesoscopic structures in the Lightning Creek Schist

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There are some structural goodies here at the confluence of the Rapid River and the Salmon River in west-central Idaho. I visited these outcrops three weeks ago on a field trip after the Rocky Mountain section meeting of GSA. The rocks are the Lightning Creek Schist, a schist that’s part of the Wallowa Terrane, an … Read more

Friday fold: Riggins, Idaho

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There are some folds in this stunning west Idaho landscape. Perspective is looking toward the north, more or less. See if you can find them: Link GigaPan by Callan Bentley One example that will probably be obvious at first glance is this syncline/anticline pair, differentially weathered, with subvertical axial traces, and an apparently shallow plunge … Read more

Friday fold: core

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At the Rocky Mountain Section meeting of the Geological Society of America this week, there were several displays of interesting cores. I’m not sure where this one came from, but it had a fold in it, and since no one else had volunteered a Friday fold for this week, I took a photo: It’s standard … Read more

Friday fold: 3D syncline in Macigno Formation

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Alan Pitts is the source of today’s fold, a beautiful 3D model of a differentially-weathered sycline in the Late Oligocene to Early Miocene deep water Macigno Formation from western Tuscany, Italy. Here’s a photo: Now for the 3D model, hosted by Sketchfab; After it loads, use your mouse to grab this thing and finesse it … Read more

Friday fold: Crumpled Dinwoody Formation, Sheep Mountain, Wyoming

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Today for your folding pleasure, I give you two field GigaPans shot by Jeffrey Rollins, a two-time Rockies field course alumnus and Old Dominion University student working under my colleague Declan De Paor, assisted by NOVA student Bridget Gomez, during last summer’s extended GigaPan expedition at the Sheep Mountain Anticline, Wyoming. This particular outcrop was … Read more

Friday fold: disharmony in the Old Lyme Gneiss

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Happy Friday – it’s the end of a very busy week for me, and I hope you too are looking forward to a fun and rejuvenating weekend. Here’s your Friday fold – like last week, a guest submission from Joe Kopera: Wowzers; that’s a looker! What are we looking at here? Joe writes: This photo … Read more

Friday fold: Siccar Point video from BGS

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The British Geological Survey just came out with a new video on Siccar Point, featuring some excellent drone video of the site (in very good weather!). In addition to the unconformity, one of the things you will appreciate about the video is an excellent end-on view of a plunging synform exposed just above waterline: You’ll … Read more

Friday fold: Catalina Island #3

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Happy Friday – sorry to have not shared any folds with you last week. I hope these beautiful folds in Catalina Island meta-cherts will make up for it: As with the previous couple of Friday folds, this image is courtesy of Sarah Penniston-Dorland (University of Maryland, College Park).

Friday fold: Catalina Island #1

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My friend Sarah Penniston-Dorland, of the University of Maryland, supplied this week’s Friday fold. it comes from Catalina Island, California, where Sarah just wrapped up some field work with two of her students. All three of them have given me permission to post the images here: The Catalina Schist is a suite of subduction-related metamorphic … Read more

Friday fold: Harpers Ferry

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The geology east of Harpers Ferry, West Virginia, is cool. It’s Blue Ridge rocks, from basement to the cover sequence, tilted to the west and broken and repeated by the Short Hill Fault. Here’s a look at a detail of the Geology of the Harpers Ferry quadrangle by Southworth and Brezinski (1996). So there’s a … Read more

Friday fold: Nice gneiss from Salt Lake, Utah

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Another guest Friday fold… this one from my colleague Tiffany Rivera of Westminster College in Salt Lake City, Utah, the one who brought you yesterday’s thrombolite pictures… Tiffany writes that these shots come from a man-made boulder field / berm along the lake. The boulders were these beautifully folded gneisses. Antelope Island exposes some of … Read more