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.
featured
The Old Man of Hoy, a sea stack in Orkney
A sea stack on the west coast of Orkney showcases Devonian sedimentary strata and implies terrific storm waves in its geomorphology.
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.
Ten years of Mountain Beltway
Callan has been blogging about geology for a decade. Here are a few reflections on those ten years behind the wheel of “Mountain Beltway.”
The #FaultCup semifinals
Over the past few weeks, there’s been a fun game playing out on Twitter, hosted by Jorge (@lithospheric), called The Fault Cup, or #FaultCup in Twitterspeak. There’s a bracket showing one-on-one match ups between different faults, and then a 24 hour Twitter poll is posted, where the audience can vote for which one they want … Read more
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.
My GSW Presidential address
I can hardly believe it but tonight I wrap up my tenure as the 2017 President of the Geological Society of Washington. In our Society, it’s a tradition for the President to give the final talk of the year, a Presidential Address that takes up the entirety of the final regular meeting. I’ll be talking … Read more
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.
People and Pyroclastics: Mount Agung at the Confluence of Science and Society
A guest post from an American expat living in east Bali, displaced with his family from their home due to Mount Agung’s recent eruption, and trying to help out as best he can.
Visiting the K/Pg boundary at Bottaccione Gorge, near Gubbio, Italy
A trip to one of the most famous outcrops in the world, a place with a stratum that marked a profound shift in the state of the planet, and a profound shift in geologic thinking. Plus, for the author, it’s a romantic journey back in time.
Friday fold: soft sediment deformation in California’s Castaic Formation
The guest Friday fold comes to us from the Miocene of California, deposited in a releasing bend basin along the San Andreas Fault.
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
VGFC 2017: Limbs of arkose
The 2017 Virginia Geological Field Conference had a heavy arkose infusion. Meet some of these feldspar-rich Neoproterozoic sediments of the Lynchburg Group.
Pompeii vs. Herculaneum
Italy’s celebrated archaeological site of Pompeii is compared and contrasted with nearby Herculaneum in terms of art, architecture, visitor experience, and (of course) geology.
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.
Friday fold: Dextral asymmetry in a shear zone, Italy
The Friday fold comes from highly foliated rocks in a shear zone near Tyrol, Italy. It was contributed by reader Samuele Papeschi.
Big earthquake in southwestern Mexico, M8.1
The M8.1 southwestern Mexico earthquake is discussed and placed in context.
Friday fold: Eagle Rock
For the Friday fold, Callan digs out images of Eagle Rock, Virginia, well aged in his digital archive for a decade!
A suite of new 3D models
A showcase of five new 3D digital models of awesome rock samples and outcrops, produced using Agisoft Photoscan.
Friday fold trio: Samples from UNM, ABQ
It’s Friday and that means “fold time” here at Mountain Beltway. Today, we feature a trio of samples on display in the halls of the Department of Earth and Planetary Sciences at the University of New Mexico.