Reader Jacob Langseth sent in this image of a lovely fold that he recently saw in the Blue Ridge province of Georgia. It’s located in an old CCC rock quarry, off of the Pine Log Creek Trail system, in Bartow County. You can click on that first image to make it bigger and see a … Read more
You’re looking here at Mount Kidd, a peak in the Front Ranges of the Canadian Rockies that displays a tight anticline/syncline duo superimposed on the strata of the Rundle Group. Located on the west side of Highway 40, the Kananaskis Trail, south of the trans-Canada Highway, this mountain shows us what happens with Carboniferous-aged carbonates … Read more
The Friday fold is a gorgeously deformed “duplex structure” in Mesozoic limestones of southwestern Montana.
The Friday fold is a beautiful straight-limbed antiform from coastal Greenland, courtesy of photographer Alistair Knock. Check it out and see if you can find anything that Callan didn’t annotate.
My man Walcott contributed a lot of images to the USGS stockpile during his travels. Today, I’ll feature one from Bishop, California, from 1894: Got it from here. Rock hammer on the left for scale. The caption reads: Plicated layers of thin bedded chert in limestone etched by erosion, Lower Cambrian (?). Hill two miles … Read more
That’s from the side of route 287, somewhere between Fort Collins, Colorado, and the Wyoming border. Though I took this shot >6 weeks ago on my outward-bound trip, today I find myself back in Fort Collins on the eastward leg of my summer road jaunt. And you know what one does in Fort Collins. Happy … Read more
Here’s one of the first things as you drive north from Chief Mountain in Glacier National Park, and cross the border into Alberta: The mountain in the middle is Crandell Mountain, and it looms to the north above the village of Waterton Lakes, but the lovely folds it displays are best viewed from a more … Read more
Folded quartzofeldspathic vein in amphibolite, Wyoming Terrane basement complex, Montana.
That’s my Rockies co-instructor Pete Berquist, in the regulation uniform of an orange down vest, holding a subtly-folded slab of sandstone (it’s a very slight “S”), rescued from amid the shaley wastes of the Blackleaf Formation, the Cretaceous aged sedimentary rocks beneath the Lewis Thrust on the Blackfoot Reservation, just east of Glacier National Park. … Read more
Today, the Friday fold is a fake! Looks like a nice set of asymmetric antiforms and synforms, right? But it ain’t! It’s naturally wiggly; primary not tectonic. The photo shows nothing more than differential erosion of hematite that was deposited by groundwater in permeable sandstone. It’s Liesegang banding! These hematite blobs are in the sandstone … Read more
Spotted this in Cascade Canyon, in the Tetons of Wyoming, last weekend: Nice asymmetric antiforms and synforms in the gneissic layering of the Archean basement rocks exposed there. Also, we saw a bull moose. More on that later on, when I get more time.
While out in the field with Butch Dooley last week, making major discoveries like I do, I was very impressed with the landscape-scale west Bighorn monocline, which takes formerly horizontal Madison limestone and skews it to a westward dip where the mountains end and the intermontane basin begins. It’s totally sweet. Check it out in photo form and gigapan, too.
A boulder outside the door of the Geological Museum in Laramie, Wyoming. Purty, parasitic, passive folds… Happy Friday. My field course starts tomorrow here in Bozeman. I’ll soon have a lot less time for blogging. Brace yourself.
This Friday, I give you a fold from the shores of the Rockfish River, south of Charlottesville, in Virginia’s Blue Ridge basement complex, and just down the road from the Lawhorne Mill High Strain Zone. The fold distorts (and improves) a felsic dike cutting the darker granite of the basement. You can make this (stitched … Read more
The Friday fold features fine faults from a forgotten font, and a failed foto-finding forage.
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Today’s Friday fold takes me back 25 years, to when I visited the Outdoor Lab with my science class in Arlington County Public Schools. I revisited this exemplary outdoor education facility on Tuesday, at the invitation of its director, Neil Heinekamp. Neil wanted a geology “expert” to take a look at their rocks, and I … Read more
Today’s Friday fold comes to us from Alistair Knock on Flickr*, via Dave Schumaker’s Geology News Blog, where there is a daily Flickr feed of photos tagged with the word “geology”: Bigger version here. The fold in question, an overturned synform, is at a place called “Butt of Lewis” (the northernmost point on the island … Read more
Last week, the Friday fold featured a kinked phyllite of unknown provenance that is currently resident in David King Hall 2074 on the campus of George Mason University. However, on Tuesday of last week, I found another kinked phyllite, this one out in the real world, at Thoroughfare Gap, in the Harpers Formation of the … Read more
Kink bands in phyllite. Another sample from the GMU teaching collection. Ruler in the background shows blurry mm-scale demarcations. Happy Friday — enjoy your weekend!