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1 June 2010
Butter Buster animation
A million years ago, I posted about my inaugural attempt to use the Butter Buster to illustrate shear zone deformation to my structural geology students. Today, using the UnFREEz program to make an animated GIF (Thanks, Lockwood!), I give you the Butter Buster animation:
30 March 2010
Sugarloaf
Sunday morning, NOVA adjunct geology instructor Chris Khourey and I went out to Sugarloaf Mountain, near Comus, Maryland, to poke around and assess the geology. Sugarloaf is so named because it’s “held up” by erosion-resistant quartzite. It’s often dubbed “the only mountain in the Piedmont,” which refers to the Piedmont physiographic province. Here’s a map, made with GeoMapApp and annotated by me, showing the general area: A larger version of …
24 February 2010
Snowy décollement
Earlier in the month, during the big snowstorms, my window got plastered with snow. This snow formed a vertical layer which then deformed under the influence of gravity. Looking at it through the glass, I was struck by how it could serve as a miniature analogue for the deformation typical of a mountain belt. Let’s start our discussion by taking a look at an iPhone photograph of the snow: So …
18 February 2010
Salamander shear
Whilst discussing how to quantify strain with my GMU structural geology students recently, I hit upon a cool analogy. In order for you to understand the analogy (assuming you’re not a structural geologist), I’ll have to review some background information first. Stick with it, and I promise you a salamander at the end. Structural geologists are interested in how rocks deform. If we have some idea of the original shape …
8 February 2010
Normal fault in hedgetop snow stratum
Intersection of 16th Street and Columbia Road NW… … a wee bit underexposed, eh? Guess the high albedo blew out my iPhone camera. (glove for scale)
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.