6 May 2013
Brallier Formation 1: primary structures
Posted by Callan Bentley
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:
The Brallier is turbidites, shed off the Acadian Orogeny during the Devonian, kind of like Martinsburg Formation is turbidites shed off the Taconian Orogeny during the Ordovician.
I saw plenty of trace fossils there…
There were also some non-biogenic primary sedimentary structures, like graded beds:
Here are two mud chip rip-up clasts in a graywacke block:
A few blocks showed Bouma sequence details:
I’ll return to this same site tomorrow, for a look at the secondary (tectonic) structures…
Where did you get those awesome scale bar pencils?
It’s a joint production between Little River Research & Design and the Geo2YC division of the National Association of Geoscience Teachers. At an upcoming GSA or AGU meeting, visit the NAGT booth or the LRRD booth to claim a free pencil!