Callan Bentley West of Shell, Wyoming, on route 14, there is a lovely exposure showing the tilted stratigraphic contact between the lower Tensleep Formation (purple; Pennsylvanian period) underneath Goose Egg Formation (orange/tan; Permian to Triassic in age). The contact dips to the west because it has been deformed during Laramide mountain-building (uplift of the Bighorn block, and … Read more
Can you tell me why I am very excited to be holding this rock in my hand? (iPhone photos; apologies for the low quality. But the rock… is anything but low.)
Visiting Butch Dooley and crew on a dinosaur dig in the Jurassic Morrison Formation on Wednesday morning, I did a lot of wandering around the area, dubbed the Two Sisters site. I noticed something in the sandstone at the top of one hillock, and thought it looked like a sauropod footprint: (The depression is filled … Read more
A boulder outside the door of the Geological Museum in Laramie, Wyoming. Purty, parasitic, passive folds… Happy Friday. My field course starts tomorrow here in Bozeman. I’ll soon have a lot less time for blogging. Brace yourself.
These are the geobloggers that I was privileged enough to hang out with this last week, in chronological order: Steve Gough of Riparian Rap: Ed Adams of Geology Happens: Evelyn Mervine of Georneys: Alton Dooley of Updates From the Vertebrate Paleontology Lab: Garry Hayes of Geotripper: Geobloggers are good people. They blog because they like … Read more
Another thing I saw last week in the Rockfish Conglomerate were several nice examples of “bookshelfing,” which is when a rock or mineral fractures into pieces, and the pieces slide down relative to their neighbors, like a set of encyclopedias slumping outward on a bookshelf. This has the effect of shortening the grain/clast in one … Read more
Callan presents a gazillion photos from a field trip to examine the Rockfish Conglomerate, a potential Snowball Earth glacial outwash facies from the Neoproterozoic of the Virginia Blue Ridge province.
A scene from last Thursday morning, when I left DC: Crossing from Colorado to Wyoming today; Bozeman tomorrow night!
The current edition of the Accretionary Wedge geology blog carnival (hosted by Evelyn Mervine of Georneys) is built around the theme of favorite geology words. My favorite geology word is derived from the French boudin, for sausage. It’s “boudinage,” and it’s best said with a heavy French accent and a leering, dirty expression. “Boo-din-ahhdj” I … Read more
This Friday, I give you a fold from the shores of the Rockfish River, south of Charlottesville, in Virginia’s Blue Ridge basement complex, and just down the road from the Lawhorne Mill High Strain Zone. The fold distorts (and improves) a felsic dike cutting the darker granite of the basement. You can make this (stitched … Read more
Callan attends a field trip in the Blue Ridge of Virginia, looking first at a Paleozoic shear zone that disrupts (and improves) Mesoproterozoic basement complex rocks.
Two macrobugs from yesterday’s field trip to the Rockfish River area south of Charlottesville… … a really fast orange-and-maroon grub: …and an elegant fly: We also saw some rocks, but I’ll have to blog about them later because right now I have to pack up for summer travels.
I just drew up a little checklist for the different formations my Rockies students will be seeing next starting next week out in Montana: The original black and white images (two columns on two pages) come from Self-Guided Field Trips Near Bozeman (1982), by Stephan G. Custer, Donald L. Smith, Molly Walker, and 1982’s crop … Read more
The Friday fold features fine faults from a forgotten font, and a failed foto-finding forage.
Callan gets ready for a summer of travels out in the Rocky Mountains, including teaching a field geology course, participating in a workshop about teaching energy, visiting the Burgess Shale, and… getting married!
Spied this lovely cricket while hiking the White Oak Canyon Trail in Shenandoah National Park yesterday: I realize there’s been a pretty high bugs : rocks ratio on Mountain Beltway of late; I’m just in summer mode, I reckon. And Virginia’s arthropod profligacy keeps bringing me into contact with these extraordinary segmented denizens of the … Read more
On Monday when I went to Powell’s grave, I noticed a few “boulder with a plaque” gravestones, the most distinctive of which was this lovely chunk of rose quartz: Quartz is a good choice, since it’s very very very stable at Earth surface conditions, and thus will stick around a lot longer than, say, a … Read more
Callan visits the grave of John Wesley Powell, second director of the USGS and explorer of the Grand Canyon, on an afternoon in Arlington National Cemetery.
Yesterday, I took about fifteen members of the DC Science Writer’s Association on a walking tour of DC’s geology. I was honored to present the capital city’s epic geologic story to an esteemed crowd of professional science writers from Nature, Science, the National Academies, the National Institutes of Health, the Washington Post, and other institutions. … Read more
It’s a morning for big bugs, evidently. Chris Town found a giant water bug on the other side of the planet, and as I arrived on campus, I found a female patent leather beetle crossing the parking lot. I imaged her a couple of different ways – a macro photo pair with my Canon Elph, … Read more