Whilst hiking at Dolly Sods over the weekend, I found this old artifact: Upper 10 is apparently a “Sprite”-esque lemon-lime soda, discontinued in America but still being marketed abroad. But that wasn’t what got me jazzed, of course. Look more closely… That is a lovely little conchoidal fracture, and it’s so exquisite because it preserves … Read more
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
Tension gashes are small veins that open up when rocks get stretched. Often, they are arrayed en echelon with respect to other tension gashes, all oriented in the same direction. Here is a sample of tension gashes I found this summer in rip-rap (i.e., not in situ) at some building site in New England. (I … Read more
After my thesis defense at the University of Maryland, my mentor and friend E-an Zen asked me if I had ever heard of the Purgatory Conglomerate. I had not. Over the years, E-an has been a great source of new ideas and information to me, and so when he raises a notion, I pay attention. … Read more
In my previous post, I introduced you to the Petersburg Granite, as it is exposed south of Belle Isle, at the falls of the James River in Richmond, Virginia. I mentioned that it was fractured, and I’d like to take a closer look at those fractures today. The geologically-imparted fractures were exploited by human granite … Read more
Last Friday, NOVA colleague Victor Zabielski and I traveled down to Richmond, Virginia, to meet up with Chuck Bailey of the College of William & Mary, and do a little field work on the rocks exposed by the James River. Our destination was Belle Isle, a whaleback-shaped island where granite has been quarried for dimension … Read more
In the 1987 comedy Planes, Trains, and Automobiles, John Candy and Steve Martin have a funny experience. It involves a cozy hotel room (one bed only) and the two travelers are huddled up for warmth. As he wakes up, John Candy thinks he is warming his hand “between two pillows.” At hearing this, Steve Martin’s … Read more
Today, you get a photo from GMU structure student Nik D. This is a small exposure in the Hampshire Formation (Devonian) on New Route 55 in West Virginia. It shows a fine example of plumose structure with the not-often-seen concentric ribs running perpendicular to the ‘plumes.’ At the edge of the joint, you can see … Read more
Today, our theme is vesicles. Here are some images of vesicles in basaltic lava flows in the Owens Valley of California, the same spot where we saw the baked fanglomerate that I showcased a few days back. In this photo (and the zoomed-in detail shot below), you can see a couple of things. One is … Read more
A quick post to share a few images of an outcrop I visited last September out in California’s Owens Valley. This is a spot where alluvial fans coming off the eastern Sierra Nevada were overrun by a basaltic lava flow (Jeff, Kim, Fred, and Kurt for scale): The unofficial term for these conglomerates deposited by … Read more