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21 April 2010
Blobiform
Whilst poking about Sunday on the fine exposures along West Virginia’s new route 55, my structural geology students and I noticed some joint surfaces decorated with pyrolusite dendrites. But I also found a nice slab which had one surface covered with a thicker coat of manganese oxide, and here the habit was botryoidal, like little bunches of grapes. A few photos for you: Because I don’t care as much for …
More mud
Remember the mud I saw on Pimmit Run? Turns out that West Virginia mud pulls many of the same tricks as Virginia mud. Here’s some mud cracks I noticed on Sunday afternoon on the shoulder of New Route 55 in eastern West Virginia: Notice how West Virginia spices her mudcracks with chunks of Silurian quartzite and fresh crabgrass. A tasty combination!
20 April 2010
Where on Google Earth? #199
For the first time ever, I have won a Where on Google Earth? that Ron Schott hosted, heavy on the clues. Now that it’s my turn to host, I’d like to spice things up a bit with a dynamic view. Using Google Earth’s historical imagery feature (the little “clock” button up top), I managed to see this suite of very different views of the exact same spot over time: Click …
19 April 2010
Eastern Worm Snake
While on our structural geology field trip this week, my GMU students and I encountered an eastern worm snake, Carphophis amoenus amoenus. The little charmer at first reminded me of a boa, like the ‘rubber boa’ I once found in California (a real animal, not made of rubber), and then I convinced myself it was a glass lizard… But upon the return to civilization, I was able to consult several …
17 April 2010
Fine fellows
What do I have in common with luminaries like Mike Fay, James Balog, and Stuart Pimm? We’re all this year’s cadre of Fine Fellows, recipients of free Gigapanning equipment and training (at a conference in Pittsburgh in November) on how to use it. Ron Schott is of course the king of geology Gigapanners, though he has some competition, and my acquisition of a Gigapan robot will up the ante a …
16 April 2010
Mud
A few more photos from Pimmit Run … of mud. This mud has lots of interesting features, including dessication cracks showing lovely 120° triple junctions connecting up with their neighbors, raindrop impressions, and animal tracks. Tracks of at least three species here: (Clicking on this one will make it bigger) Mud: not as fascinating as some things, but it can share some modest insights.
15 April 2010
Crenulation lineation
Hiking last Sunday in Rock Creek Park, DC, I saw this boulder and my eye was immediately drawn to the linear pattern running from upper left towards lower right (Swiss Army knife at upper right for scale): Because that photo is not especially large, let’s zoom in a bit to two sections… Here is Photo 1, annotated to show the areas we will look at next: Here’s a cropped and …
14 April 2010
Using bedding / cleavage to detect overturned beds
One of my students wrote to me this morning with a question about the relationship between bedding, cleavage, and folding. He asked: I am not sure how we use the relationship between bedding and cleavage to interpret fold limbs. It seems if bedding is near vertical and cleavage is closer to horizontal, this would be an upright fold limb. To be overturned, wouldn’t the bedding need to be closer to …
Photos from Eyjafjallajökull
My friend Barry R., now residing in PostDocVille, Denmark, took a trip to Iceland last week to check out the eruption of Eyjafjallajökull. Unfortunately, by the time he got to the volcano, it was no longer spouting lava, but the scene is dramatic regardless. You can sample some of his photos below, or see the whole album on Facebook. Waterfall: Glacial terminus and moraine: Ash on ice (steam rising beyond …
12 April 2010
John McPhee reading
The Lilster and I caught John McPhee give a reading tonight at our local uber-cool bookstore. Check it: First time I’ve seen McPhee live. Great stuff!
Callan Bentley teaches 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.