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31 July 2020

Friday fold: Two Mile Run Overlook

I spied an anticline last weekend while engaging in a day of solo geologizing along Skyline Drive in Shenandoah National Park. At Two Mile Run Overlook, I gazed west toward the southern tip of Massanutten Mountain, and noted what appeared to be an anticline in the Blue Ridge foothills: Annotated: And here it is in Google Maps,  with the perspective rotated to looking ~along strike to the north, and I …

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14 June 2019

Friday fold: kinked cleavage at Harpers Ferry

Last weekend was the annual meeting of the eastern section of the National Association of Geoscience Teachers. On Friday afternoon, we visited Harpers Ferry, West Virginia, and my colleague Beth Doyle led a great field trip to examine the rocks exposed there. This was my favorite outcrop we saw: Here is a close up of this outcrop, which is framed by (anthropogenic) rock wall: Dipping shallowly from upper left to …

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9 June 2018

Friday fold: contorted carbonates of the Conestoga Formation

Today, in Millersville, Pennsylvania, on the campus on Millersville University, I saw these contorted carbonates. They are of the Cambrian Conestoga Formation, and I saw them on a NAGT Eastern Section field trip led by Lynn Marquez of Millersville University. This deformation is purported to be Taconian, but it looks very much like Alleghanian deformation in similar aged and composition rocks in Virginia. Interesting!

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30 March 2018

Friday fold: Recumbent Harpers

Stop the presses! This late-breaking Friday fold has just been submitted here at Friday Fold Headquarters. This is from Philip Prince/Virginia Division of Geology and Mineral Resources: It’s a recumbent fold of Harpers Formation metasandstone in the James River Face area. Pretty lovely exposure. This outcrop would make a good 3D model. Happy Friday to all. Hope it’s a good one!

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1 March 2018

A GIGAmacro view of a cool outcrop in Scotland

As noted previously, the old way of viewing gigapixel imagery is no more. But there is a new, better way. The GIGAmacro company has a better viewing platform that can be used either with images uploaded to their server or  with pre-existing images that currently “live” at GigaPan.com. Here’s an example: a roadcut of limestone of the Grudaidh Formation (Durness Group) in the Northwest Highlands of Scotland, near Ardvreck Castle, …

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16 June 2017

Friday fold: toothpasty Tomstown

I spent last weekend at the National Association of Geoscience Teachers’ Eastern Section meeting, based out of the Community College of Baltimore County in Catonsville, Maryland. One of the two field trips I took headed out to the western Piedmont, Blue Ridge and Valley & Ridge provinces of western Maryland. On that trip, we took a tour of Crystal Grottoes, a commercial cave south of Boonsboro. I was impressed at …

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5 May 2017

Friday fold: sea monster in stone

It’s Friday, the end of the workweek, but also the beginning of the celebration of folded rocks. Examine a particularly sinuous example from the buckled Cambrian limestones of Canada’s Kootenay National Park.

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20 September 2016

A virtual field trip to examine the Peninsula Sandstone on Table Mountain

Take a virtual field trip to Table Mountain, near Cape Town, South Africa. Digital media to explore from the site include: a 3D model, 3 GigaPans, and a 360° spherical photo!

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3 September 2016

Viewing the Sea Point migmatite through the lens of GigaPan

It was five years ago when I first visited Sea Point, the outcrop on the coast of the Cape Peninsula where the Cape Granite (~540 Ma) intrudes the (meta-)sedimentary rocks of the Malmesbury Group. The outcrop is (a) beautiful and evocative, and (b) of historical importance, as Charles Darwin visited it while on the voyage of the Beagle, contemplating and confirming Lyell’s assertions of the validity of plutonism as he …

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30 August 2016

Northwest Highlands unconformities (3 of 3): Sub-Ardvreck

It’s time to cover the third and final unconformity I observed this summer in the North-West Highlands of Scotland: the unconformity between the Neoproterozoic Torridonian Group below and the Cambrian Ardvreck Group above. Where I saw it, south of Loch Assynt on the mountain called Beinn Garbh (north of Canisp), it actually is displayed alongside the sub-Torridonian unconformity. The mountain hosts a “double unconformity”! Here is a view, looking south: …

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15 March 2016

Timberville

Join Callan for a virtual field trip, as he shares dozens of photos from a recent ‘field review’ of a new geological map in Virginia’s Valley & Ridge province. Highlights: graptolites, trace fossils, geopetal structures, folds and faults.

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12 October 2015

Bedding/cleavage GigaPans at Harpers Ferry, WV

I’ve been thinking lately about Harpers Ferry, the spot where West Virginia, Virginia, and Maryland meet, at the confluence of the Potomac River and the Shenandoah River. I’ve noted small outcrops of its overturned beddding here previously, and also described a book I read about the man who made the place infamous: John Brown. I went out there again last week with my NOVA colleague Beth Doyle, and we explored …

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12 September 2015

New GigaPans from Team M.A.G.I.C.

Hampshire Formation outcrops on Corridor H, West Virginia: [gigapan id=”178008″] link (Marissa Dudek) [gigapan id=”177198″] link (Callan Bentley) Faults in the Tonoloway Formation, Corridor H, West Virginia: [gigapan id=”176602″] link (Marissa Dudek) Conococheague Formation, showing stromatolites and cross-bedding: [gigapan id=”177155″] link (Callan Bentley) [gigapan id=”177355″] link (Jeffrey Rollins) Tiny folds and faults, from a sample I collected somewhere, sometime… oh well, it’s cool regardless: [gigapan id=”178807″] link (Robin Rohrback) Fern …

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25 December 2014

The stromatolites of Helen Lake 2: GigaPans

Posted this morning as my “Christmas gift” to blog readers in both photo and GigaPan form, here are the exquisite stromatolites of Helen Lake, Banff National Park, Alberta. [gigapan id=”159358″] link [gigapan id=”159462″] link [gigapan id=”159461″] link [gigapan id=”159459″] link [gigapan id=”159458″] link [gigapan id=”159355″] link [gigapan id=”159359″] link Finally, three other non-stromatolitic GigaPans from the site: One of Artomys Formation siltstone / shale interbeds… [gigapan id=”159354″] link …and two …

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8 August 2014

Friday fold: Buckle vs. passive folding in the Chancellor Group slates

The Friday fold is an outcrop in Yoho National Park that showcases differences between buckle folding and passive folding.

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23 April 2013

Return to the Outdoor Lab

Two years ago, I took a trip to the Phoebe Hall Knipling Outdoor Lab, which is Arlington, Virginia’s outdoor education facility in the Pond Mountains (southern continuation of the Bull Run Mountains), on the eastern edge of the Blue Ridge geologic province. I was invited back last week to look at some new exposures. I brought the GigaPan along. There had been additional erosion on the saprolitic exposure of Harpers …

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12 March 2013

Five new GigaPans from Thoroughfare Gap

Yesterday, I took five new GigaPans at Thoroughfare Gap, a water gap where Broad Run cuts through Bull Run Mountain, the eastern limb of the Blue Ridge Anticlinorium at my latitude. The rocks here are the Cambrian-aged Chilhowee Group, with bedding tilted moderately to the east during Alleghanian mountain-building in the late Paleozoic. To the west is the crystalline core of this massive regional fold, and to the east is …

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8 February 2013

Friday fold: LIDAR view of the Weverton Formation along the Blue Ridge front

Dan Doctor of the US Geological Survey contributed this week’s Friday fold. It’s a lovely view of the asymmetric folds in the Cambrian-aged Weverton Formation (part of the Chilhowee Group, a Sauk-Sea passive margin transgressive sequence), exposed on the western flank of the western limb of the Blue Ridge Anticlinorium. It’s a LIDAR image, and it’s best viewed when draped over the scenery in a Google Earth view. Here’s a …

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2 January 2013

Upturned Paleozoic strata on Highway 16, Bighorns, Wyoming

Here’s a terrific outcrop to start off the new year at Mountain Beltway. We’re back in the Bighorns of Wyoming here, on highway 16, traversing the southern portion of the range en route from Buffalo to South Pass City. Click to enlarge Annotated, expanded, and Easter-egg-embedded: Click to enlarge From a different perspective (uphill a tad, looking north), consider this GigaPan I shot at the time: [gigapan id=”83585″] link The …

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17 April 2012

Strained Antietam Formation sandstone

I collected this sample the weekend before last on the Blue Ridge Thrust Fault field trip led by Alan Pitts. It’s a chunk of the Antietam Formation quartz sandstone, a Cambrian beach deposit. The face we photographed measures 15 cm by 12 cm. [gigapan id=”103122″] link It definitely looks best in full screen mode, so please feel encouraged to click through and explore it a bit. You’ll notice some great …

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