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24 June 2016

Friday fold: Dalradian schist at Cushendun, Northern Ireland

Friday fold: Dalradian schist at Cushendun, Northern Ireland

Same beach as the Cushedun conglomerate post earlier in the week – but here we see the schist into which the rhyolite dikes intruded: It’s been folded! Happy Friday. Hope your weekend is rejuvenative and fun.

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17 June 2016

Friday fold: isoclinal flow structures in Icelandic lava

Friday fold: isoclinal flow structures in Icelandic lava

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 the lavas as they erupted at the surface. Happy Friday!

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10 June 2016

Friday fold: Mesoscopic structures in the Lightning Creek Schist

Friday fold: Mesoscopic structures in the Lightning Creek Schist

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 accreted chunk of crust that docked with western North America during the Mesozoic. Here is …

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3 June 2016

Friday fold: Riggins, Idaho

Friday fold: Riggins, Idaho

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 of the axes to the south: A more subtly expressed example is on the hill …

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27 May 2016

Friday fold: Castile Formation GIGAmacro

I’ve posted here before about the extraordinary intra-layer folds in the varved evaporite deposits of West Texas’ Permian Basin, but today I can go one better and offer a GIGAmacro look at these lovely folds: Link GIGAmacro by Callan Bentley Enjoy checking these amazing small-scale folds out. They will boggle your mind.

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20 May 2016

Friday fold: core

Friday fold: core

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 core diameter; I’d guess that’s about 2 inches. Given that I’m headed out on an …

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13 May 2016

Friday fold: 3D syncline in Macigno Formation

Friday fold: 3D syncline in Macigno Formation

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 around. What an outcrop! What a great 3D model! Thanks for sharing this, Alan!

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22 April 2016

Friday fold: Crumpled Dinwoody Formation, Sheep Mountain, Wyoming

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 found near the axis of the massive Laramide fold, and shows an extensively deformed section …

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15 April 2016

Friday fold: Shiny pahoehoe

Friday fold: Shiny pahoehoe

James Farrell is our newest Friday fold source. Today he shares a primary (not tectonic)  fold – the fold is in the ropy texture of a pahoehoe flow: Those colors! What a gorgeous rock. Thanks for sharing, James! You, too, can share your folds here. Send me your images. I look forward to featuring them on the Friday fold!

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11 March 2016

Friday fold: disharmony in the Old Lyme Gneiss

Friday fold: disharmony in the Old Lyme Gneiss

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 shows geologic mapper and structural geologist Greg Walsh (USGS) explaining disharmonic folding to assembled geologists …

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