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
Callan shows off a new hallway display in his building at Northern Virginia Community College, showcasing the numerous geologic provinces of northern Virginia (as well as adjacent mid-Atlantic states).
Callan pays a visit to the grave of celebrated paleontologist and geological administrator Charles D. Walcott.
The weekly example of a fold is especially… “cool” this week.
Okay, now just what the heck is going on in these pictures? (All of them can be enlarged by clicking through.) The photos are different views of the same crystal. It is a broken hexagonal prism of quartz, fading to amethyst at the distal end, found by Doug Dupin of northwest DC during the excavation … Read more
It’s that time of year for me… summer’s here, and I’m winding up my duties at NOVA in preparation for some travels. We leave Sunday night for two weeks in Turkey, followed by my regional field geology course in Montana (also two weeks), followed by some family time and mountain climbing in New Hampshire (three … Read more
Chris Barr’s informative website of the “Accidental Museum of Paleontology” that can be found in D.C. building stones is now live. You should go and check it out, and if you ever visit the city, you can use it as a guide for your tourism.
Heat-stressed map of the Chesapeake Bay / Washington, DC region, as seen at Kenilworth Aquatic Gardens. Looks like mudcracks, eh? Similar stresses; similar strains.
“The Geotaggers’ World Atlas #8: Washington, DC” by Eric Fischer If you like maps, you should go check out these images by photographer Eric Fischer. (via here) The different colors represent different modes of transportation: Black is walking (less than 7mph), red is bicycling or equivalent speed (less than 19mph), blue is motor vehicles on … Read more
Hiking last Sunday in Rock Creek Park, DC, I saw this boulder and my eye was immediately drawn to the linear pattern running from upper left towards lower right (Swiss Army knife at upper right for scale): Because that photo is not especially large, let’s zoom in a bit to two sections… Here is Photo … Read more
My girlfriend’s mom was in town in January, and we took her down to visit the Capitol Building. The tour had a good bit of history, but definitely missed the opportunity to talk geology. I was particularly struck by the columns in the Hall of Statuary: Close up of one column, with my hand for … Read more
On last May’s GSW spring field trip to Chain Bridge Flats, I saw a quartz vein: Surely, upon looking at this photograph, you will be struck by the way the vein is not the same thickness along its length, and parts of it appear to be a white line transitioning into a parallelogram, and back … Read more
A few photos from last May’s spring field trip with the Geological Society of Washington… Here’s the group at Chain Bridge Flats (far westernmost-Washington, D.C.), looked at the metamorphic rocks there — a metagraywacke melange known as the Sykesville Formation. Another group shot, with field trip leaders Tony (khaki shirt) and Gary (red jacket) Fleming … Read more
Mark your calendars! Prehistoric: D.C. will profile (part of) the ancient past of Washington, D.C., in an episode to air February 28, 9pm, on the Discovery Channel.
A look out the back window as DC breaks its annual snowfall record…