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23 May 2017

Silurian tidal flat carbonates of the Tonoloway Formation

Silurian tidal flat carbonates of the Tonoloway Formation

Journey to the Silurian period in what is today the Valley & Ridge province of eastern West Virginia to see some exquisite sedimentary rocks that represent deposition in a very arid, very shallow setting.

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9 May 2017

Ripples in Foreknobs

Ripples in Foreknobs

The Foreknobs Formation is a Devonian unit in the Valley & Ridge province of the Mid-Atlantic Region. It was deposited in relatively shallow near-shore conditions during the Acadian Orogeny. On a field trip to Corridor H, a new highway transecting the West Virginian Valley & Ridge province on Monday, I stopped to document a couple of beds showing very nice ripple marks. These ones are symmetrical, and thus likely represent …

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26 April 2017

Pseudocraters at Lake Mývatn, Iceland

Pseudocraters at Lake Mývatn, Iceland

Near the southern end of Lake Mývatn, astride the Mid-Atlantic Rift in northern Iceland, lies a field of “pseudocraters” that result from steam explosions beneath a fresh lava flow. Put on your head-net and join us to check it out!

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6 April 2017

Stac Fada

Stac Fada

The evidence for a meteorite impact origin for the Stoer Group’s Stac Fada member seems to stack up. Engage in a virtual field investigation on Mountain Beltway.

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28 March 2017

P-sol in a conglomerate countertop slab

P-sol in a conglomerate countertop slab

A hardware parking lot in rural Virginia showcases an elegant slab of pressure-solution induced compaction of a conglomerate.

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9 February 2017

Gabion

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 …

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7 February 2017

Basaltic strata, faulting, and glaciation in western Iceland

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 …

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16 January 2017

Shear zones in Scottish gabbros

Shear zones in Scottish gabbros

A quest to visit the “first shear zones” described in the scientific literature leads to an alternate location, and some GIGAmacro images of samples from the real, original spot.

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13 January 2017

Friday fold: Smaull Graywacke at Saligo Bay, Islay

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.

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30 December 2016

Friday fold: one from the archive

Friday fold: one from the archive

As noted previously, my colleague Declan De Paor recently retired from Old Dominion University, and I was lucky enough to inherit some of his rock samples. I’ve been making super-high resolution images of the samples ever since. Here’s a particularly striking fold, weathered out differentially. Enjoy exploring it – and have a happy final Friday of 2016! Link 2.04 Gpx GIGAmacro by Callan Bentley (If the embedded GigaPan doesn’t work …

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