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22 December 2017
The #FaultCup semifinals
Over the past few weeks, there’s been a fun game playing out on Twitter, hosted by Jorge (@lithospheric), called The Fault Cup, or #FaultCup in Twitterspeak. There’s a bracket showing one-on-one match ups between different faults, and then a 24 hour Twitter poll is posted, where the audience can vote for which one they want to advance to the next round. Click through to embiggen. If you’ve missed the fast …
5 December 2017
The quarry in Contessa Gorge
Central Apennine stratigraphy and structure is on display in the wall of a quarry in Contessa Gorge, Italy. Have a look a nice normal fault and a submarine mass transport deposit.
29 September 2017
Friday folds: soft sediment deformation in thin sections of MTD sandstone
The Friday folds are small soft-sediment deformational features within a dismembered, folded sandstone (a “ploudin”) from a mass transport deposit from the latest Devonian of West Virginia.
11 August 2017
Friday fold: Eagle Rock
For the Friday fold, Callan digs out images of Eagle Rock, Virginia, well aged in his digital archive for a decade!
7 February 2017
Basaltic strata, faulting, and glaciation in western Iceland
Today, let’s journey to Iceland, to a bit northwest of Reykjavík. This is a view from the top of the Grábrók cinder cone, across the valley to the east. With very few exceptions, Iceland is a big pile of basalt, and that shows through in the walls of this valley, which display a stack of basaltic lava flows, intercalated in places with pyroclastic debris or volcaniclastic sediment. One portion of …
13 January 2017
Friday fold: Smaull Graywacke at Saligo Bay, Islay
On the western coast of Islay, Saligo Bay showcases turbidites of the Neoproterozoic Colonsay Group. The Smaull Graywacke shows Caledonian (late Ordovician) folding and cleavage superimposed on world-class graded bedding. There’s also a nice dolerite dike to examine.
21 October 2016
Friday fold: a miniature ramp and flat
Sometimes you find big ideas in small places. Here, a South African chert boulder mimics in miniature fold and thrust belts the world over.
23 September 2016
Friday fold: Shetland geopark rock wall at Northmavine
Can a Friday fold be a work of art as well as a source of geologic insight? The answer can be found as you enter Shetland’s Northmavine region.
9 September 2016
Friday folds: A study in contrasts at the Walls Boundary Fault, Shetland
A virtual field trip to the Walls Boundary Fault in Shetland reveals an embarrassment of Friday fold riches.
30 June 2016
Virtual field trip to Siccar Point, Scotland
Time for another virtual field trip on the Geologist’s Grand Tour of the United Kingdom: the most famous outcrop in the world. Today, we visit Siccar Point, Scotland. You’ve probably already seen photos of this place – they usually look something like this: To those who aren’t familiar, here’s what going on: There are two sets of strata here – and the contact between them is an ancient erosional surface. …
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.