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.
Friday Fold
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 … Read more
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.
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!
Friday fold: Himalayas, northern India
My colleague Martin Schmidt of the McDonogh School, who I know through the National Association of Geoscience Teachers eastern section, recently shared a bunch of fold photos with me. They have a “dated” feel because they were originally shot on slide film, but the folds themselves of course are timeless. I’ll be featuring a bunch … Read more
Friday fold: Apennine phyllites
Another one from Samuele Jæger Papeschi: NE verging recumbent F2 folds in Paleozoic phyllites – Filladi di Buti fm., Punta Bianca, N. Apennines, Italy
Friday fold: recumbent folds in metapelites and metalimestones, Apennines, Italy
Anotehr one from Samuele Jæger Papeschi: Recumbent SW verging folds in alternating metalimestones and phyllites in the Metacalcari e Filladi formation, seen at Anisian, Punta Bianca, La Spezia, N. Apennines, Italy
Friday fold: Apennine crenulation cleavage
My new social media buddy Samuele Jæger Papeschi and I collaborated on some goofy maps in August, but then he noticed my Friday folds, and like the very best human beings anywhere, Samuele offered to pitch in with a few folds of his own. (Other readers are encouraged to do the same!) Today, I’ll feature the first … Read more
Friday fold: cherts at Mount Diablo, California
My former student James O’Brien recently moved out to the left coast, and posted some photos earlier this week of a hike he took at Mount Diablo State Park in the mountains east of the San Francisco Bay area of California. There are some classic-looking Franciscan cherts exposed there, as these folded examples show: Seeing … Read more
Friday fold: Macro GigaPan of Archean gneiss, Spanish Peaks, Montana
I don’t think I’ve featured this sample here before… It’s a lovely gneiss from near the trailhead for the Spanish Peaks, near Ted Turner’s Ranch in the Gallatin/Madison Range in southern Montana, not too far from Big Sky. Have fun checking it out in this macro GigaPan: link Happy Friday to all.
Friday fold: Prins Christian Sund, Greenland
This Friday, we are off looking for folds in South Greenland. Care to join?
Friday fold: a kink fold at Baldwin Gap
Ladies and gentlemen, I give you… The Friday fold: This beauty came to my attention on Monday, when I was lucky enough to go on a field trip with my friends Leigh and Mary. They are founding members of our local informal geology club, and we have been meaning to take a Cedar Creek field … Read more
Friday fold: Yin-Yang at Swift Dam
What is Matt looking at here? Matt was one of my Rockies students this summer, a geology major at the University of Virginia. Together with another UVA student and students from Mary Washington University and George Mason University, Matt embarked on a mountain-climbing hike during our evening camping at Swift Dam, near Depuyer, Montana. The … Read more
Friday fold: a return to the duplex structure in the Gastropod Limestone
Some time ago, I featured as Friday fold the extraordinarily complex duplex structure to be seen in the Cretaceous “gastropod limestone” member of the Kootenai Formation at Sandy Hollow, Montana. Today, let’s take a deeper look through a couple of hand-shot GigaPan images: Here’s the bigger of the two: link Here’s one with students for … Read more
Friday folds: Fox’s and Foch’s
A final Friday fold (for now) from Howard Allen: This is : A view south across Kananaskis Lakes, Peter Lougheed Provincial Park, Alberta, through mist/low-hanging clouds. Snow highlights the Sarrail Creek Syncline and Warspite Anticline on the north faces of mounts Fox (left/east) and Foch (right/west). Rocks are Lower Carboniferous carbonates of the Banff, Livingstone … Read more
Friday fold: Lawson Syncline and Mount Inflexible
View of Lawson Syncline looking obliquely along strike (SSE) from an unnamed peak SW of Mount Inflexible, Kananaskis Range, Alberta. The axis of the syncline forms the bottom of the valley and plunges slightly toward the south. The syncline is in the hanging wall of the Sulphur Mountain Thrust sheet. On the right side of … Read more
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 … Read more
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!
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 … Read more
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!