You are browsing the archive for April 2018 - Mountain Beltway.
27 April 2018
Friday fold: Cape Liptrap
Sandra McLaren of the University of Melbourne is the source of today’s guest Friday Fold. Let’s join her on a journey with her students to Cape Liptrap (southeast of Melbourne in Victoria, Australia) on a lovely day: What a spectacular place. (We have featured folds from this site previously.) Happy Friday all!
25 April 2018
Natural Bridge State Resort Park, Kentucky
A visit to a natural sandstone arch (or “bridge” as the locals call it) in eastern Kentucky yields unexpected bonuses, like fossil wood, Liesegang banding, and the honeycomb-like weathering pattern called “tafoni.”
24 April 2018
An astonishing rise in the number of humans
One interesting thing about reading T. rex and the Crater of Doom, by Walter Alvarez in 2018 is the change in world population since it was first published in 1997. In explaining to his readers how to think about measurements in “parts per billion,” Alvarez explains his mental shortcut to appreciating those numbers. He says something along the lines of “since there are 5 billion people in the world, a …
T. rex and the Crater of Doom, by Walter Alvarez
Walter Alvarez has a new book out, and its publication reminded me that though I read and appreciated The Mountains of St. Francis, I had never read his most famous work — the account of how he and his father and a team of other researchers zeroed in on an extraterrestrial impact explanation for the end-Cretaceous extinction. So last week I read T. rex and the Crater of Doom (1997). …
20 April 2018
Friday fold: Isoclinal in Damaraland
A guest Friday fold from Graham Andrews of West Virginia University: Graham describes this as an almost along axis view of a huge isocline in the Damaraland belt, Namibia Thanks for sharing! And a happy Friday to all.
18 April 2018
Visiting St. Francis’s lovely limestone
The Cretaceous-Paleogene limestone called Scaglia Rossa was used to construct a basilica in tribute to St. Francis. Let’s head to Assisi and take a look.
13 April 2018
Friday fold: Blue Ridge gneiss in the University of Kentucky rock garden
The Friday fold is on display in a rock garden outside the Department of Earth and Environmental Sciences at the University of Kentucky.
10 April 2018
An outcrop showcasing a strand of the Kentucky River Fault System
Roadcuts in Kentucky show Ordovician limestones of two distinct types, replete with fossils and primary sedimentary structures, and juxtaposed by a fault, one strand in the Kentucky River Fault System.
9 April 2018
Orthocone nautiloids of the Lexington Limestone
I took a trip last week to Kentucky. My colleague Kent Ratajeski from the University of Kentucky took me out on a nice all-day field trip to examine some of the local geology. I was particularly impressed with the large straight nautiloid fossils that abounded in the Ordovician-aged Lexington Limestone. Here are a series of photos I took of these orthocones, all on pavement exposures (horizontal bedding planes) with my …
6 April 2018
Friday fold: “wrecumbent in Wrangellia”
Darrel Cowan of the University of Washington has pitched in a Friday fold. Check this lovely scene out: Darrel says this is a recumbent fold in the Upper Triassic Nizina and Chitistone limestones. I took the photo when I worked for Shell in 1973 or 1974. I’m pretty sure it is on the west wall of the canyon occupied by the Root Glacier, several kilometers NW of McCarthy, Alaska. The …
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.