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5 December 2016
Cinder cones in Iceland (with lichen)
What makes an Icelandic cinder cone even better? A coating of fuzzy lichens, perhaps…
24 October 2016
GIGAmacro views of komatiite
Erik Klemetti posted today at Eruptions about komatiite, which is apropos, considering I just finished imaging some samples of that ultramafic volcanic rock. Have a look at three samples from Barberton Greenstone Belt here, each from the 3.27 Ga Weltevreden Formation: Link GigaPan by Callan Bentley Link GigaPan by Callan Bentley Link GigaPan by Callan Bentley And, while we’re at it, here’s one from the Red Lake Greenstone Belt (~3.0 …
6 October 2016
Oddball Icelandic rocks, part I: A green ignimbrite
Iceland does basalt really, really well. But there are a few non-basaltic igneous rocks to be found there, too. One of them is a green ignimbrite (pyroclastic conglomerate) that crops out in coastal Berufjörður, eastern Iceland. Check it out!
21 September 2016
Stađarbjargavík
Based on this photo, what do you think Stađarbjargavík might have to offer? If you guessed columnar jointing in basalt, you’d be right! Looking down the fjord, south of Hofsós (in Iceland): The place is basically a series of miniature Giant’s Causeways, full of unpopulated exemplars of cooling columns! Little coves separate the small peninsulas, each filled with rounded column bits: Here’s a spot where one more is about to …
15 September 2016
Pillow basalts from eastern Washington: a 3D model
Since I showed off some Icelandic pillow basalts yesterday, today I thought I would showcase a new 3D model of big pillows in Columbia River basalt of eastern Washington, taken from a photo set I made when I was out there in May:
14 September 2016
Pillows in Icelandic basalts
Time is short these days, but I know you hanker for amazing geology. How about some pillow basalts from the Snæfellsnes* Peninsula, far western Iceland? Note the cm-demarcated pencil for scale. See if you can find it in the GigaPan version below: Link Handheld GigaPan by Callan Bentley, stitched with Microsoft ICE _________________________ * “Snay full snooze”
4 July 2016
Virtual field trip to Kinkell Braes, Scotland
Walking along the shore east from St. Andrews, Scotland, along the seaside sandstones of Kinkell Braes, you encounter several extraordinary examples of geology. It’s a great place for the next stop on our Grand Tour of the geology of the British Isles. Here’s the scene: The first stop is a giant eurypterid trackway, potentially the largest invertebrate trackway in the world (Whyte, 2005), on the underside of an overhanging sandstone …
18 May 2016
Pillow basalt exposures in the Columbia River basalts
Pillow basalts form when mafic lava erupts underwater. Here are several examples from the Miocene Columbia River flood basalts, a large igneous province in eastern Washington state.
20 April 2016
Cooling columns of the Catoctin Formation, Indian Run Overlook, Shenandoah National Park
An inaugural visit to an outcrop in Shenandoah National Park reveals the signature of lava flows ~600 million years old.
15 April 2016
Friday fold: Shiny pahoehoe
James Farrell is our newest Friday fold source. Today he shares a primary (not tectonic) fold – the fold is in the ropy texture of a pahoehoe flow: Those colors! What a gorgeous rock. Thanks for sharing, James! You, too, can share your folds here. Send me your images. I look forward to featuring them on the Friday fold!
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.