It has been a while since I’ve reviewed any kids’ books here, but this one was so good that I just have to tell you about it. My son is now 6 and a half years old, and he’s interested in all sorts of natural history topics. Given that I’m a geologist, he’s probably more … Read more
Hampshire Formation outcrops on Corridor H, West Virginia: link (Marissa Dudek) link (Callan Bentley) Faults in the Tonoloway Formation, Corridor H, West Virginia: link (Marissa Dudek) Conococheague Formation, showing stromatolites and cross-bedding: link (Callan Bentley) link (Jeffrey Rollins) Tiny folds and faults, from a sample I collected somewhere, sometime… oh well, it’s cool regardless: link … Read more
The answer to this week’s geological interpretation contest is revealed, sort of. Annotations, GigaPans, and outcrop detail photos reveal the story of equatorial fluvial incision and ancient slumping during the Carboniferous ice ages.
Another Friday, another Friday fold from Howard Allen: Folds in near-vertical beds, north side of Grizzly Creek, Opal Range, Alberta. Beds are Carboniferous carbonates, Mount Head and Etherington formations. Enjoy your day!
Kate Littler sent in this Friday fold, via Twitter: lovely parasitic folds in the Carb limestone, West Angle Bay south Wales. Awesome. Looks like a great place. Thanks, Kate! Happy Friday!
Two nice new examples of soft sediment deformation structures in Pennsylvanian-aged clastic sedimentary rocks from West Virginia.
While out at the eastern section of NAGT’s annual meeting last weekend in West Virginia, I participated in a field trip to look at the stratigraphy of the Bolt Mountain section of Pottsville Group strata. One thing that was particularly eye-catching about the sandstones we saw was that many of them had been stained by … Read more
Twitter follower Bob J. submitted this week’s Friday fold: Carboniferous cyclothems at Scremerston, Northumberland. Thanks Bob!
Have a gander at this: Given that this is a Friday on Mountain Beltway, you might expect to see a fold here, and indeed, there’s something wavy and high-contrast running through the center of this sample. But that’s no fold. It’s a fossil plant! A “reed” of some kind, I guess. You can also see … Read more
A young-Earth creationist reinterprets one of Callan’s blog posts in light of a Biblical flood. Callan responds with a demonstration of how new information can change a true scientist’s mind, but no amount of data can convince someone whose conclusions are based on faith rather than empirical data.
Yesterday we examined primary sedimentary structures (including trace fossils) at an outcrop of Devonian-aged Brallier Formation turbidites between Deerfield and West Augusta, Virginia. Today, we’ll zoom in on the tectonic structures at the site: folds, faults, and joints. Remember, you don’t have to take my word for it. You can explore it for yourself in … Read more
The Friday fold photo was taken this morning on a GigaPanning expedition, and shows a small syncline within turbidite strata of the Martinsburg Formation, Page Valley, Virginia.
During Alleghanian deformation (late Paleozoic), the Cub Sandstone we looked at yesterday was tilted to near vertical at Catherine Furnace. The shale layers developed cleavage at this time, and there was evidently some flexural slip between sandstone layers, to judge from these fine slickensides: Students: Can you deduce the sense of motion from the orientation … Read more
An outcrop of the Ordovician-aged Martinsburg Formation is used to illustrate the development of slaty cleavage, and hence a major transition in the Rock Cycle.
Here’s another video, wherein I’ve made some improvements from the last one (reserved the lower right corner for the webcam “talking head” video inset, and adjusted the microphone for fewer audio blowouts). It’s still not perfect – there’s a disconnect between the audio and the webcam video that becomes more and more pronounced throughout the … Read more
On Monday, I was out in the field at the Blue Ridge / Valley & Ridge transition (“boundary”?) in the Elkton East quadrangle, where Chuck Bailey and students (from the College of William & Mary) were leading a field review of their new geologic map. A field review is a form of field-based peer review, … Read more
One of Callan’s former students leads a field trip to examine the western edge of the Blue Ridge geologic province, attempting to answer the question of whether the Blue Ridge / Valley & Ridge contact is indeed the trace of a thrust fault. Breccias and S-C fabrics tell part of the story…
Callan visits a new outcrop of highly-sheared rocks in the basement complex of Virginia’s Blue Ridge province.
Giant City State Park is a patch of protected forest south of Carbondale, Illinois, where there are some pretty cool exposures of Pennsylvanian-aged Makanda Sandstone. Here’s a typical look at one: Notice the deep chasm on the right. This leads, maze-like, to other flat-bottomed and vertically-walled canyons: The orthogonal joint sets produces some nice tall, … Read more
You’re looking here at Mount Kidd, a peak in the Front Ranges of the Canadian Rockies that displays a tight anticline/syncline duo superimposed on the strata of the Rundle Group. Located on the west side of Highway 40, the Kananaskis Trail, south of the trans-Canada Highway, this mountain shows us what happens with Carboniferous-aged carbonates … Read more