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3 July 2015

Friday fold: Opal Range, Alberta

Friday fold: Opal Range, Alberta

Howard Allen is the Friday folder who keeps on giving… Here’s his latest: Multiple folds at top of ridge, Opal Range, Alberta. Photographed from Kananaskis Highway 40, looking SE. Beds are Carboniferous carbonates, probably Mount Head and/or Etherington formations. There are lots of great folds to be seen along that road. The Kananaskis Trail is in the “tourist shadow” of the nearby Trans-Canada Highway, which means it’s well worth your …

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26 June 2015

Friday fold: Subvertical carbonates

Friday fold: Subvertical carbonates

Another Friday, another Friday fold from Howard Allen: Folds in near-vertical beds, north side of Grizzly Creek, Opal Range, Alberta. Beds are Carboniferous carbonates, Mount Head and Etherington formations. Enjoy your day!

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19 June 2015

Friday fold: subglacial drag fold (Pleistocene) in Cretaceous sediments, Alberta

Friday fold: subglacial drag fold (Pleistocene) in Cretaceous sediments, Alberta

Howard Allen, a retired petroleum geologist from Calgary, and longtime reader of this blog, contributed this week’s Friday fold: Subglacial drag fold (Pleistocene) in Upper Cretaceous Horseshoe Canyon Fm. bedrock (sandstone, shale). The locality is SE of Drumheller, AB at UTM 12U 394247 5692469 (WGS84). Did you hear that right? Yes, you did: This is Cretaceous aged sedimentary rock, folded by a Pleistocene glacier, tens of millions of years after …

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12 June 2015

Friday fold: Flow banding in obsidian, Newberry Volcano National Monument, Oregon

Friday fold: Flow banding in obsidian, Newberry Volcano National Monument, Oregon

Lockwood Dewitt is the purveyor of this week’s Friday fold ensemble: All these folds are primary (not tectonic) in nature: they are flow banding of the viscous lava that oozed out to make the Big Obsidian Flow at Newberry. And closer in: One more: Awesome stuff! Thanks for sharing, Lockwood! Happy Friday, everyone!

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29 May 2015

Friday fold: Hayward neighbor

Friday fold: Hayward neighbor

The Friday fold is some crumpled sedimentary rock near the Hayward Fault in California.

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15 May 2015

Friday fold: Crumpled Carboniferous cyclothems

Friday fold: Crumpled Carboniferous cyclothems

Twitter follower Bob J. submitted this week’s Friday fold: Carboniferous cyclothems at Scremerston, Northumberland. Thanks Bob!

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8 May 2015

Friday fold: Foreknobs formation

Friday fold: Foreknobs formation

Last one in the triumverate sent in by reader Eric Fulmer: Annotated: Happy Friday and (for many of you) happy end of the semester!!

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1 May 2015

Friday fold: Tight syncline/anticline pair in Brallier Formation

Friday fold:  Tight syncline/anticline pair in Brallier Formation

The Friday fold shows clastic detritus (turbidites or “flysch” from the Acadian Orogeny) crumpled into tight folds due to the later Alleghanian Orogeny.

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24 April 2015

Friday fold: Bloomsburg Formation at lime kilns on C&O Canal

Friday fold: Bloomsburg Formation at lime kilns on C&O Canal

Milepost 127.4 (High, 2001) on the C&O Canal: …Cool if you’re into history. …Cool if you’re into economic geology. …Cool if you’re into Friday folds!   Reader Eric Fulmer sent me this photo (along w/ two others you’ll see in weeks to come). Thanks, Eric!

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27 March 2015

Friday fold: Isla Escarpada, Chile

Friday fold: Isla Escarpada, Chile

I’m very nearly delinquent on posting the Friday fold… Here you go – a Google Earth view of a differentially-weathered fold partly above and partly below sea level in Chilean Patagonia, south of Puerto Natales: They call it Isla Escarpada. Awesome. Here’s a Google Maps link if you want to explore it yourself. Happy Friday!

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