You are browsing the archive for faults Archives - Mountain Beltway.
16 August 2018
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 multiple varieties of deformation there. First off, there was straight-up brittle extension, resulting in bedding-perpendicular …
10 April 2018
Roadcuts in Kentucky show Ordovician limestones of two distinct types, replete with fossils and primary sedimentary structures, and juxtaposed by a fault, one strand in the Kentucky River Fault System.
23 March 2018
Snow may have cancelled the geology class, but there’s plenty to see outside! Join us for a tour of three fine examples of physical analogues in snow that show deformation akin to that we observe in rocks under tectonic stresses.
23 January 2018
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.
30 December 2017
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.
22 December 2017
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 to advance to the next round. Click through to embiggen. If you’ve missed the fast …
5 December 2017
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.
29 September 2017
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.
11 August 2017
For the Friday fold, Callan digs out images of Eagle Rock, Virginia, well aged in his digital archive for a decade!
7 February 2017
Today, let’s journey to Iceland, to a bit northwest of Reykjavík. This is a view from the top of the Grábrók cinder cone, across the valley to the east. With very few exceptions, Iceland is a big pile of basalt, and that shows through in the walls of this valley, which display a stack of basaltic lava flows, intercalated in places with pyroclastic debris or volcaniclastic sediment. One portion of …