My student Troy was working on the geologic history of the Thoroughfare Gap regions for his Honors project this semester, and we went out there last week to check out some stuff. One thing I was struck by was how much more deformed these rocks were than I had expected. This was particularly evident in … Read more
The Friday fold is a contorted chert sample from Turkey.
My friend JT, who got her MS in geology at the University of Maryland when I did, is now at the Colorado School of Mines working on her PhD in Environmental Science and Engineering. A water main broke outside her house this morning, and I’m pleased that her first thought was to photo-document the resulting … Read more
I shot this gigapan (900 images) last Thursday during the lunch break of the annual “Geology of Virginia” symposium hosted by the Commonwealth of Virginia’s Department of Geology and Mineral Resources. It shows the rock garden outside the DGMR’s offices in Charlottesville, a place where they have collected charismatic megasamples from across the state’s five … Read more
Another group of interesting cobbles from the same sand and gravel pit that I described earlier in the week: Here’s the same sample, gone all animated, for your perspectivizing pleasure: What we’re seeing here is some fine-grained gray colored rock (siltstone, I guess?) that’s developed a pronounced weathering rind marked by a large amount of … Read more
Hoo boy. This one made me yelp… While on the glacial geology of western Pennsylvania trip last Saturday, we visited a gravel quarrying operation. The operators were extracting gravel from a glacial lake delta deposit, and it was full of glacial outwash — sediments washed out from the melting front of the Erie lobe of … Read more
A week ago Saturday, my three Honors students and I went on a field trip led by Gary Fleeger of the Pennsylvania Geological Survey, to examine some cool glacial features in western Pennsylvania. The trip was associated with the joint meeting of the northeastern & north-central sections of the Geological Society of America, held in … Read more
At last weekend’s northeastern / north-central GSA meeting in Pittsburgh, David Saja of the Cleveland Museum of Natural History presented a talk entitled, “Geometric Analysis of Folded Greywacke Layers from Pacheco Pass, California.” [Abstract link] In addition to the standard PowerPoint presentation that 99% of GSA speakers use, David also brought in some hand-samples (what … Read more
Saw this beauty on a field trip Saturday, examining the glacial geology of western Pennsylvania. Note the faceted surfaces and profusion of scratches of multiple sizes in multiple orientations.
Background geology of the Sugarloaf Mountain area. (March 2010) Primary structures in the meta-sandstone of the Sugarloaf Mountain Quartzite. (yesterday) Background on tension gashes. (August 2010)
You’ll recall that I detailed a trip to Sugarloaf on this blog back in March of last year. Well, on Saturday (March of this year), Lily and I returned to this distinctive knob of quartzite for a five-mile hike. Along the way, we saw plenty of metamorphosed quartz sandstone (now quartzite), which was similar to … Read more
I first mentioned the Waterfall Formation on this blog in May of 2008, but this was my first time visiting it in situ. Previously, including the May 2008 visit, was memorable time with charismatic boulders of float. The occasion to see this geologic unit in outcrop was the field trip 6 days ago with the … Read more
Callan joins some students from George Mason University on a field trip to the rock exposures at Thoroughfare Gap, Virginia, where meta-sedimentary rocks are exposed in the eastern Blue Ridge province.
Here’s your Friday fold, straight from the canyon of the Jefferson River, near Cardwell, Montana. Perspective is to the south. East is on the left; west is on the right. Bigger version This is right next to the outcrops of LaHood Conglomerate that I mentioned earlier this week. My Rockies course co-instructor Pete Berquist and … Read more
Remember the LaHood Conglomerate? Here’s a few field photos of my Rockies class visiting it last July: Amphibolite clast: Marble clast: I love how well-rounded these clasts can be — like eggs. When these grains were loose cobbles, tumbling down into the Belt Sea, the Earth was only 3 to 3.5 billion years old. The … Read more
A year and a half ago, on my way back to Modesto from Yosemite, I pulled over at the side of the road and found a piece of urbanite full of whoppers. But that curiosity wasn’t what caught my eye and made me pull over in the first place. Instead, what I noticed was this: … Read more
Originally posted in September 2010 as part of this missive on the Champlain Thrust Fault. Happy Valentine’s Day!
Here’s an amazing sight that caught me unawares in Capadoccia — some paving stones outside a small “museum” (preserved Byzantine hoodoo church) that were chock full of some AMAZING trace fossils. Sense of scale is provided by a Turkish 1-lira coin, about the same size as a U.S. quarter. Check out the variety, size, and … Read more
On our second day in Capadoccia, Lily and I went for a walk through one of the valleys that are eroded into the landscape there. Bas-relief hoodoos emerging from the wall of the canyon: We came to one area with classic turret-like hoodoos: Note the gravel layers in that column’s section, and the human at … Read more
Here’s three shots of the Konnarock Formation diamictite, taken with my Nikon microscope. Field of view is about 1 cm in each shot.