Friday fold: Big Cottonwood Fm., Slate Canyon, Utah
It’s Friday and that means it’s time for a fold. Today we head to Cottonwood Canyon, Utah, with reader Octavia Spencer, for a lovely antiform.
structure
Drawing geological structures, by Jörn Kruhl
After blogging about geovisualization, reader James Safranek alerted me to this new book about two of my favorite things: drawing and structural geology! I requested a review copy from the publisher, who kindly provided one. It’s great! This is “a whole book” about drawing and geology and specifically structural geology. As such, it’s not going … Read more
Friday folds: Continuing contorted Conestoga carbonates
The first Friday of September calls out for a fold. The Burle Business Park in Lancaster, Pennsylvania has an answer – several of them, in fact!
A suite of deformational features in Lancaster limestones
In the Landisville Quarry, Lancaster, Pennsylvania, there is a quarry that cuts into Cambrian limestones. (The exact identity of these limestones is apparently a matter of some dispute, but that’s not going to stop us!) I visited the quarry in June on a field trip offered through the NAGT’s Eastern Section annual meeting. We witnessed … Read more
Chickie’s Rock, Pennsylvania
A virtual field trip to the deformed quartzites and metaconglomerates of Chickie’s Rock and Sam Lewis State Park in Lancaster County, Pennsylvania.
Deformed conglomerate of Frog Lakes, California
Fifteen years after mapping deformed rocks of the Sierra Crest shear zone system in the high Sierra, a family vacation brings Callan back to the pre-batholith metasedimentary rocks which show a pronounced strain.
Friday fold: a quartet from Marli Miller’s website
Marli Miller is a senior instructor at the University of Oregon. She is the author of Roadside Geology of Oregon and (with Darrel Cowan) Roadside Geology of Washington. She’s also a very talented geological photographer. She launched a website recently to showcase her work and make it available for instructors: Geology Pics. After chatting with … Read more
Raider of the Lost Anticlines
A solo hike in search of anticlines yields new outcrops and good views!
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 … Read more
Friday fold: Zerrissene turbidite system, Namibia
The University of Maryland’s Jay Kaufman makes our Friday fold happen by sharing some images of folds from the Zerrissene turbidite system of northwestern Namibia.
S-C fabric in limestone, Camerino, Italy
Some scaly Italian limestone shows off two foliations (S and C) which reveal the kinematic motions that built the Apennines.
Friday fold: 3D model from the Portsoy Shear Zone
The Friday fold is a really cool 3D model of differentially-weathered calc-silicate rocks in Scotland that were folded during the Caledonian Orogeny.
Friday fold: eastern Andes
This image graces the cover of the new report, Challenges and opportunities for research in tectonics: Understanding deformation and the processes that link Earth systems, from geologic time to human time. A community vision document submitted to the U.S. National Science Foundation: Make it bigger by clicking it The photo is of a landscape in … Read more
A kid and his slicks
On a family hike, Callan’s son finds some interesting smooth lines on a rock. What are they? What do they tell us? Tune in for a brief history of Appalachian geology.
SGTF field trip
A virtual field trip to the Phoenix Mountains and South Mountains of Arizona, along with participants in the 2018 Structural Geology and Tectonics Forum.
Normal faulting in the San Felipe Volcanic Field, New Mexico
A glance out the airplane window over New Mexico triggers a bit of web research and a new view of tectonic extension via Google Earth and geologic maps.
Friday fold: Alpine cross sections by Albert Heim
The Friday fold is a figure from a 1922 book about the geology of the Alps by Swiss structural geology genius and artistic master Albert Heim. Marvel at his gorgeous depiction of the internal and long-since-eroded structure of these mighty mountains.
The quarry in Contessa Gorge
Central Apennine stratigraphy and structure is on display in the wall of a quarry in Contessa Gorge, Italy. Have a look a nice normal fault and a submarine mass transport deposit.
Friday fold: Quantankerous veins
What does it mean for a vein to be “quantankerous?” Well, to start with, it’s quartz. Second, it has to be disagreeable or cantankerous. This vein, seen in meta-arkose of the Catoctin Formation near the summit of the Blue Ridge at Rockfish Gap (not Afton Mountain), is such a quantankerous individual: You’ll notice its “S” … Read more
Friday folds: soft sediment deformation in thin sections of MTD sandstone
The Friday folds are small soft-sediment deformational features within a dismembered, folded sandstone (a “ploudin”) from a mass transport deposit from the latest Devonian of West Virginia.