This photo is from the Millboro Formation: mostly deep water black shale, but with the occasional heavy turbidite coursing in and settling its bulk down on the squishy mud beneath. Some folks on our trip suggested these might be seismites: soft sediment deformation resulting from earthquake-induced vibration.
Hoo-hoo! An anticline in the hanging wall of a thrust fault in the Valley & Ridge. This is the redbeds of the latest-Ordovician Juniata Formation. Lynn Fichter for scale.
Where are some ripple marks in the Hampshire Formation. Cell phone service is a lot more localized here in West Virginia, so we’ll see how many posts I manage today…
Bedding and cleavage intersect in the Weverton Fm. Bedding = Cambrian Cleavage = late Paleozoic (Alleghanian)
Last Friday, I spent the evening riding up to New York on a bus. To pass the time, I had my iPod and a new paper by Francis Macdonald and colleagues in Science. The paper examines the timing of one of the episodes of “Snowball Earth” glaciation. There’s some important new data in this paper, … Read more
Another in the Geology Of Central Park series…
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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
So, those sediments we saw yesterday? They’re faulted in the area around the Crucifix Site. As this image shows, the style of faulting is normal faulting: Annotated with some color to jazz things up a bit: In normal faults, the upper block moves downward with respect to the lower block. They are typical of extensional … Read more
On the September 2009 GSA field forum in the Owens Valley, the final stop of our first day was to check out the so-called “Crucifix Site,” along Chalk Bluff Road (north of Bishop, California, at the southern margin of the Volcanic Tableland). It’s called the “Crucifix Site” because there is a metal cross erected there: … Read more
When I was out poking around in the woods, confirming for local geophile Barbara that indeed her local geologic map wasn’t 100% accurate, I noticed this on the frozen ground: We have seen this before, in a post back on NOVA Geoblog, almost exactly a year before I took this photo. Here’s another shot from … Read more
One of the cool things about being the local geoblogger is that people get in touch with you about local geology. Sometimes this even leads to meeting up for field trips. Here’s two quick photos from a recent (January 2010) field trip to a creek near Springfield, Virginia. My host was Barbara X, a local … 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
A friend forwarded this via e-mail to me today… U.K. readers may be interested in participating. Millstone Grit? Kimmeridge Clay? Old Red Sandstone? Durness Limestone? Yorkshire Lias? ………. What are YOUR top three British sediments? BSRG (British Sedimentological Research Group) are conducting a small survey to find out what formations geologists consider the “best” sedimentary … Read more
Since yesterday’s live-blogging the rock sample prep routine turned out blurry, I figured I owed it to this sample, and to you, to give everyone a better look. So I scanned it this morning. Penny for scale. Assuming that your computer screen is vertical, this is in the same orientation as when it was deposited: … Read more
Today during Physical Geology lab, I used our grinding wheel to plane down a turbidite sample than I collected this past December down in Chilean Patagonia. Thanks to the technological miracle of blogging via iPhone, I can send it to you in a mere 45 seconds. Enjoy the graded bed: let it transport you back … Read more
Small-scale debris flows as a muddy slurry flowed over weathered-out chunks of the Bishop Tuff. Probably about two days old. Southern edge of the Volcanic Tableland, last September.