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5 February 2016

Friday fold: Catalina Island #2

Friday fold: Catalina Island #2

Happy Friday! Here’s another fold from Catalina Island, California – an antiform in metasediments, courtesy of Sarah Penniston-Dorland of the University of Maryland:

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29 January 2016

Friday fold: Catalina Island #1

Friday fold: Catalina Island #1

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 rocks. These rocks are amphibolite facies gneisses, but part of the Catalina Schist. The metamorphic …

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15 January 2016

Friday fold: Harpers Ferry

Friday fold: Harpers Ferry

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 fault! Good – but the title of this post isn’t “Friday fault” – Where’s the …

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8 January 2016

Friday fold: Cho La Pass, Himalayas

Friday fold: Cho La Pass, Himalayas

Today’s Friday fold comes from Martin Schmidt, who has shared a few previous folds with Mountain Beltway readers. It shows a folded ptygmatic vein from the Himalayas. Pretty sweet, amiright? Thanks, Martin. Happy Friday, all!

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1 January 2016

Friday fold: Folded Mountains Ale

Friday fold: Folded Mountains Ale

My friend Eric Pyle drew my attention to this ale earlier in the week – I reckon that will do for this week’s Friday fold. Cheers! And Happy New Year!

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11 December 2015

Friday fold: Nice gneiss from Salt Lake, Utah

Friday fold: Nice gneiss from Salt Lake, Utah

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 the oldest rocks in the Salt Lake valley, but I don’t know the geology out …

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4 December 2015

Friday fold: interference patterns on Elba

Friday fold: interference patterns on Elba

Samuele Jæger Papeschi shares one more fold with us: some deformation here… type III (Ramsay…) interference pattern in Cretaceous calcschists… Cavo, Elba Island Awesome! I hope everyone has a great Friday.

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20 November 2015

Friday fold: recumbent limestones of coastal Grosseto

Friday fold: recumbent limestones of coastal Grosseto

Samuele Jæger Papeschi not only provided this week’s Friday fold, but he also serves as its sense of scale: According to Samuele, these are: folded metalimestones in Punta delle Rocchette, Grosseto. This are pretty interesting transected folds, showing about 10 degrees of foliation dip in respect to their axis Thanks for sharing, Samuele, and happy Friday, all!

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13 November 2015

Friday fold: chevron-folded chert

Friday fold: chevron-folded chert

Samuele Jæger Papeschi is the source for today’s fold: Those are: chevron-folds in radiolarian cherts – Jurassic radiolariti fm. – Quercianella – Leghorn, Italy Cool. They look a lot like the chevron-folded cherts near San Francisco. Same age, too.

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6 November 2015

Friday fold: ptygmatic in northern India

Friday fold: ptygmatic in northern India

Another image from northern India’s Himalayas, courtesy of Martin Schmidt: The “intestine-like” aspect of this fold has a descriptive adjective in geology: ptygmatic. Gorgeous! Thanks for sharing, Martin. Happy Friday!

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