I found this interesting looking slab of gray limestone last summer in the Bridger Range of Montana, in one of the talus slopes on the north side of Sacagawea Cirque. The high-contrast pattern reminded me of something, but I couldn’t say quite what. Then I realized: it looks like one of those indigenous pictographs, where … Read more
Back to Texas, today. Here’s a cross-sectioned Turitella snail from the Buda Formation limestone: It’s exposed in a block of rock on the north side of Mt. Cristo Rey. You can explore these GigaPanned blocks of the Buda in search of your own Turitella… How many can you find? [gigapan id=”129425″] link [gigapan id=”129426″] link … Read more
It’s Friday… that means it’s time for a fold. Let’s try this outcrop at “Confusion Hill” in the Franklin Mountains of West Texas: See it? Let’s zoom in… From the shadows to the left of the hammer, trace out the dark green layer… it may make you think of a box fold: …but it’s not. … Read more
Today, I initiate a series of posts based on some of the geology I saw over spring break, in west Texas and southern New Mexico, on the field exchange between Northern Virginia Community College and El Paso Community College that I helped facilitate. We spent our first morning in the field in the Franklin Mountains, … Read more
For the Friday fold, let’s journey back to the Silurian, as exposed in the limestones of that age that were deformed during Alleghanian mountain-building (Pennsylvanian and Permian), and exposed along Corridor H in eastern West Virginia. Some buckling (cuspate-lobate form) seen in that one… A little pop-up with hinge collapse: And, finally, as a digestif, … Read more
More images for you today from my field trip a few weeks ago to West Virginia’s bizarro highway Corridor H, a quiet place built for roaring traffic. Its multistory roadcuts are fresh and profound; they offer the most incredible views into the mid-to-late-Paleozoic surface of Earth… and the creatures that lived there. In the Devonian … Read more
While on Corridor H 2 weeks ago with Alan Pitts, we stopped astride the Patterson Creek Mountain Anticline, with extensive road cuts displaying Tonoloway Formation overlying Wills Creek Formation. We love this spot for its lovely folds and halite casts. See what I mean? [gigapan id=”103090″] link [gigapan id=”142740″] link This time, however, my eye … Read more
While out on the Corridor H field trip last week before the heavy snow, I found this squeal-inducingly-lovely example of a stylolite in Helderberg Group limestones (Devonian passive margin carbonates): The stylolite is a pressure-solution surface, made especially apparent in this example because of the starkly different grain sizes and colors on either side of … Read more
I went out last Tuesday to Corridor H, the exemplary new highway cutting through the Valley and Ridge province of eastern West Virginia. Joining me was former student Alan Pitts, a devotee of Corridor H from way back in the early days when we just called it “New Route 55.” The boondoggle highway is now … Read more
Another guest submission for the Friday fold. This one comes to us from Christie Rowe, and it shows a tiny kink fold in the Bitter Ridge formation (playa limestones):