Here is a trio of concentrically-zoned chert nodules in Mississippian Castle Reef Dolostone, exposed at Sun River Canyon, Montana, just downstream from the roadside outcrop of the French Thrust: If you look closely at the lowermost of the three chert nodules, you’ll see it’s been split and offset by a small fault. Here are close-up … Read more
Stylolites (pressure solution seams) in limestone of Mississippian age, exposed on the side of a rounded boulder in Hyalite Canyon, Gallatin Range, Montana. These stylolites, like most, are bedding-parallel, and thus most likely formed due to the weight of the overlying rock. Calcite, the dominant mineral, goes into solution under pressure, and insoluble material, like … Read more
While out in the field with Butch Dooley last week, making major discoveries like I do, I was very impressed with the landscape-scale west Bighorn monocline, which takes formerly horizontal Madison limestone and skews it to a westward dip where the mountains end and the intermontane basin begins. It’s totally sweet. Check it out in photo form and gigapan, too.
Here’s a gigapan I shot yesterday, looking north at the contact between the New Market and Lincolnshire Formations at the classic “Tumbling Run” outcrop south of Strasburg, Virginia: See if you can find the E. coli plush toy I included, or the cm-scale pencil! As usual, you can see it full screen, by clicking on … Read more
While exploring the Rock Creek Cemetery last week, I noticed a couple of other interesting graves. This one, made of limestone, shows nice “reverse” cross-bedding: Here; I dialed up the contrast a bit to highlight these cool primary structures: It’s “reverse” because the tilting direction of the cross-beds switches from left (at the bottom) to … Read more
Atop the glorious pile of travertine that is Pamukkale (photos 1, 2, & 3), there is an ancient ruined city called Hierapolis. It was founded by the Romans in the second century BC, and was constructed (not surprisingly) from the most common locally available stone: travertine. A tomb with a view: This last one is … Read more
Callan shares a third batch of photos from the stunning travertine terraces at Pamukkale (“cotton castle”) in central Turkey, near the town of Denizli. Travertine structures on numerous scales are shown, adorned with flowers, tourists, and ducks.
Following on from Thursday’s initial suite of Pamukkale photos, here’s some more. More later!
Callan shares some photos from his time last summer at the massive travertine deposits at Pamukkale, Turkey.
If I had a structural superpower, it would be to shoot en echelon tension gash arrays from my fingertips: Photo by Sharon Ruggeiri
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
Here’s your Friday fold, straight from the canyon of the Jefferson River, near Cardwell, Montana. Perspective is to the south. East is on the left; west is on the right. Bigger version This is right next to the outcrops of LaHood Conglomerate that I mentioned earlier this week. My Rockies course co-instructor Pete Berquist and … Read more
Hopefully seasoned readers of this blog will remember this nice chunk of limestone with pyrolusite (MnO2) dendrites growing on its surface. I took some close-ups with my Nikon microscope a few weeks ago. Here they are; enjoy! The width of the field of view in each photograph is about 1.1 cm: BTW, Mike likes dendrites, … Read more
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.
This summer, strolling atop the massive travertine terraces of Pamukkale, Turkey, I checked out the necropolis (graveyard) of Hierapolis, an ancient city founded around 200 BCE and abandoned after an earthquake in 1534. One thing that caught my eye there was this tomb, built of travertine blocks.
Picking up where we left off… I was telling you about the field trip I took through Turkey’s Tavşanlı Zone, a tectonic suture zone between fragments of continental crust that accreted during the closure of the Tethys Ocean. Day 2 of the trip dawned and we broke fast, and then headed out to a bizarre … Read more
Happy Saturday morning, everyone. I’m on my way down to the National Mall for fellow Tribesman Jon Stewart’s “Restoring Sanity” rally, but I thought I would just quickly post a little geological treat for Mountain Beltway readers. These are pisolites (basically like a big oolite, but without the biological component that would qualify them as … Read more
Right after I got to Istanbul on this most recent trip, I took a taxi from my hotel down to the Bosphorus, to check out the Rumeli Hisarı, a fort complex built in 1452 by Sultan Mehmet the II in anticipation of the following year’s siege of Constantinople. It’s constructed at the narrowest point on … Read more
My friend Dave Auldridge, formerly a structural geology student of mine at George Mason University, is now in grad school at the University of Alabama. Dave is working on an interesting project with speleothems: those drippy looking CaCO3 growths that you find in caves, like stalactites and stalagmites. He’s looking at these speleothems in order … Read more
Check it out: In the canyon of the Jefferson River, Montana, you can find yourself some limestone (Mississippian Madison Group, I think of the Lodgepole Formation) that has seen a wee bit of faulting: And here’s an annotated copy… Both of these images are enlargeable by clicking through (twice): Note the quarter for scale: this … Read more