Friday fold: Pete’s purty pet

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

Friday fold: “Hinges Cemetery” by José Julian Esteban

Cretaceous calcarenite layers, folded along the coast of Spain (?). From the repository of geological images hosted by the European Geological Union, Imaggeo. I was reminded of Imaggeo earlier this week, and it’s a great place to go browse around for cool photos of geological things. It could use a better search interface, but oh … Read more

French Thrust

That title sounds kinky, right? Well, calm down. I’m behind the curve on the latest Accretionary Wedge (as I was for the one before that), but here’s a quick image to join the parade of geologic photos that Ann is hosting. While it’s not my favorite, it’s definitely a favorite, more by virtue of the … Read more

Gerede segment of the North Anatolian Fault

The author recounts a field trip in October along the section of Turkey’s North Anatolian Fault that last ruptured in 1944. The rock types on either side of the fault are compared, offset markers are illustrated, and several types of landforms particular to strike-slip faults are shown. The post concludes with an examination of the town of Gerede itself, which is built directly atop the fault.

Accretionary Wedge #28: Deskcrops

In honor of this month’s Accretionary Wedge (geoblog carnival; this month the theme is “deskcrops”), I recorded the following short video, showcasing some samples I have in my office: stromatolite (western Montana), conglomerate (Patagonia), schist (New Hampshire), anorthosite (New York), amygdular meta-basalt (Virginia), amphibolite (California), hematite concretions (eastern Montana), and a stretched-pebble lineated meta-conglomerate (Turkey).

Friday fold: tight syncline in Montana

This fold is located on Highway 287, north of Wolf Creek, Montana. Annotated version: As with last week’s Friday Fold, this fold owes its existence to (a) deposition of sandstone and shale in the Western Interior Seaway, and (b) deformation under a giant thrust sheet during the thin-skinned compressional tectonics of the  Sevier Orogeny. In … Read more

Jointed Virgelle

One of the stops my Rockies students and I made this summer was a dinosaur paleontology tour through the Two Medicine Dinosaur Center in Bynum, Montana. The folks there are very accommodating, and at my request gave the class a bit of stratigraphic context for the dinosaur fossils. For instance, we visited the geologic formation … Read more