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2 March 2017
A virtual field trip to the Grind of the Navir
On the northwestern coast of the Northmavine Peninsula of Shetland, there is an unusual coastal landform: a gate-like entrance to an elevated amphitheater, like something out of Tolkien, and a storm beach of slab-like boulders inland of that.
9 February 2017
Gabion
Do you remember the blog post four years ago about documenting the doomed outcrops at Scientists’ Cliffs, Maryland? It was the site of gorgeous Miocene fossil exposures in the Calvert Formation. Here’s what the site looks like now: Photo by Peter Vogt That ugly thing at the base of the cliff is a gabion, protecting the houses on the clifftop and making fossil access impossible. I’m glad we got …
26 January 2017
Dore Holm
The scenic arch of Dore Holm (“Door Island”) in Shetland shows off the most efficient way of breaking a slab of rock. The island’s shape is a reflection of the parsimonious nature of natural deformation.
7 November 2016
Coastal colluvium + coal contest in context
Here’s the answer to the contest: This is an outcrop on the beach at Funzie Bay, Fetlar, Shetland, U.K. The modern beach sediment is the lightest-colored, rounded cobbles at both the top and bottom of the photo. Poking out in between is a layer of light-gray colluvium (angular fragments) overlain by dark peat, now perhaps approaching lignite. Because peat in Shetland cloaks the hillsides but is unlikely to grow a …
3 November 2016
A “triple tombolo” in northern Shetland
We’ve taken a look already at an exemplary tombolo from Shetland. Today, I’m dialing up the tombolosity of the blog with a Triple Feature: Click to make much larger (8000 pixels wide) If you look closely here, you’ll see that only the rightmost bar fully connects the two islands. It’s the only true tombolo, sensu stricto, at this site. The other two perhaps deserve another name, though I’m not sure …
7 July 2016
Tombolo at St. Ninian’s Isle, Shetland
I came to Shetland for the rocks – but I’ve been surprised and delighted by the huge range of interesting coastal geomorphology to be seen here too. I’ve never seen so many sea stacks, wave-cut cliffs, and bayhead bars in my life. One that is so “classic,” so “textbook” that I couldn’t resist it, is the tombolo that connects St. Ninian’s Isle to mainland Shetland. In Google maps, it couldn’t …
22 September 2014
Sea arch in pyroclastic deposits, Santorini, Greece
A series of blog posts on the geology of Santorini and Athens, Greece begins with a look at a sea arch on the south shore of Thera.
1 April 2011
Friday fold: “Hinges Cemetery” by José Julian Esteban
Cretaceous calcarenite layers, folded along the coast of Spain (?). From the repository of geological images hosted by the European Geological Union, Imaggeo. I was reminded of Imaggeo earlier this week, and it’s a great place to go browse around for cool photos of geological things. It could use a better search interface, but oh well. It’s worth it to see images that are both geologically informative and beautiful, like …
20 December 2010
GoSF2: Basalt
Second in the on-going series about the geology of San Francisco: this post explores the pillow basalts of the Marin Headlands Terrane.
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.