You are browsing the archive for May 2013 - Page 2 of 3 - Mountain Beltway.
14 May 2013
An itty bitty brachiopod
Found this small, flat brachiopod fossil last fall just down the road from my place in the Fort Valley. Lovely little thing… That’s all I’ve got for you today!
13 May 2013
Monday macrobug: Flight of the termites
Termites can fly. But not all termites. Around here, the only flying termites are the reproductives – the fertile males and females that a termites colony produces periodically. It seems to be associated with the advent of spring. I spotted this group a couple of weeks ago, when I noticed the sunlight catching in their diaphanous wings. They hatch, emerge en masse, and take to the air, seeking a partner …
11 May 2013
The latest flood on Passage Creek
We had another flood on Passage Creek on Wednesday, and into Thursday morning. Here are a few photos and GigaPans for those of you who like flood imagery: link link link Making GigaPans of the scene: Some images of the flood itself: Aftermath: http://www.gigapan.com/gigapans/129490 http://www.gigapan.com/gigapans/129543 http://www.gigapan.com/gigapans/129569 10.3 feet was the maximum gauge height this time (6 is bridge level), which means the stream is putting out 4200 cubic feet of …
10 May 2013
Friday fold: New Market / Lincolnshire formation contact, Staunton, Virginia
Happy Friday! Here’s a view of the folded contact between the (older, lower) New Market Formation, and the (younger, upper) Lincolnshire Formation, as exposed in Staunton, Virginia: The contact has been folded, pretty intensely: The New Market Formation is massive, light-colored, and exhibits fenestral texture here. The Lincolnshire is darker, more thinly-bedded, and is chock full of fossil invertebrates. Explore it for yourself in this M.A.G.I.C. GigaPan: link A closer …
9 May 2013
Boudinage in northern Minnesota
This is my final post on the pre-GSA-Minneapolis structural geology field trip to the Superior Province. The photo above shows a roadcut exposure of boudinage in xenolith-bearing Vermillion Granitic Complex. Here’s another, smaller, more brittle example of boudinage, from another site, the following morning: Gee, it only took me 1.5 years to blog that trip in its entirety… Sheesh!
8 May 2013
A comparative look at the Klingle Valley outcrop
A week ago, I featured six new GigaPans here, of the extraordinary rocks in Klingle Valley, DC. I hadn’t been able to get the next phase of imaging that site ready in time for the post, but here it is: an annotated view of the outcrop. Annotation color code: PINK = Granite contact BLUE = Sericite after staurolite pseudomorphs YELLOW = Outlines of stretched clasts within the metaconglomerate GREEN = …
7 May 2013
Brallier Formation 2: tectonic structures
Yesterday we examined primary sedimentary structures (including trace fossils) at an outcrop of Devonian-aged Brallier Formation turbidites between Deerfield and West Augusta, Virginia. Today, we’ll zoom in on the tectonic structures at the site: folds, faults, and joints. Remember, you don’t have to take my word for it. You can explore it for yourself in this M.A.G.I.C. GigaPan: link One thing that’s kind of cool about that GigaPan is the …
6 May 2013
Brallier Formation 1: primary structures
Last week, I mentioned some geologizing with the family in the Staunton area. The furthest west we ventured was to the road connecting Deerfield, Virginia, with West Augusta. There, the Brallier Formation is well exposed in a dramatic roadcut. Explore it for yourself in this M.A.G.I.C. GigaPan: link The Brallier is turbidites, shed off the Acadian Orogeny during the Devonian, kind of like Martinsburg Formation is turbidites shed off the …
3 May 2013
Friday fold: Baxter and the boulders
Last weekend, after we checked Lily in for her race, I spotted some boulders near the check-in site. The next morning, once the race had started but before we could cheer her on, my field assistant and I went back to the boulders to check them out. My field assistant’s planners had forgotten to pack him a hat – so we improvised with a pair of fleece pants inverted on …
2 May 2013
A coiled nautiloid, namesake of a vintage
Callan and his family visit a Virginia winery that features tasty libations and chunky nautiloid fossils, both products of the same local geology…
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.