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You are browsing the archive for sandstone Archives - Page 2 of 8 - Mountain Beltway.

27 June 2016

Small faults in upper Old Red Sandstone, Dunbar, Scotland

Dunbar, Scotland, is a nice little seaside town that also happens to be the birthplace of the conservationist John Muir. My family and I have been based out of here this week on our European geological GigaPan expedition. But on our first morning, upon visiting Siccar Point (which is nearby), I threw out my back, and spent most of the next two days recuperating. I did manage a short walk …

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16 May 2016

Trace fossils in the Massanutten Sandstone

Over the weekend, my wife and I took a walk with our son at the Storybrook Trail, an accessible trail with a fine overlook to the east over the Page Valley. There, the Massanutten Sandstone shows a bunch of big beefy trace fossils at this site: both bedding-parallel (Arthophycus-like) and bedding-perpendicular (Skolithos-like) traces. Here’s Bax on a photogenic slab of the quartz arenite, showing the inch-wide bioturbation: A short distance …

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15 March 2016

Timberville

Join Callan for a virtual field trip, as he shares dozens of photos from a recent ‘field review’ of a new geological map in Virginia’s Valley & Ridge province. Highlights: graptolites, trace fossils, geopetal structures, folds and faults.

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19 August 2015

Iron oxide sweat stains in sandstone

What do a sweaty baseball cap and fractured sandstone have in common? Episodes of absorption of dirty liquids that pile up material such as iron oxide at the soaking front.

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21 May 2015

Soft sediment deformation in sandstone and shale, Bolt Mountain

Two nice new examples of soft sediment deformation structures in Pennsylvanian-aged clastic sedimentary rocks from West Virginia.

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20 May 2015

Liesegang banding in Pennsylvanian sandstones, Bolt Mountain, West Virginia

While out at the eastern section of NAGT’s annual meeting last weekend in West Virginia, I participated in a field trip to look at the stratigraphy of the Bolt Mountain section of Pottsville Group strata. One thing that was particularly eye-catching about the sandstones we saw was that many of them had been stained by rusty groundwater, producing the lovely stripey pattern known as Liesegang banding. Here are five examples: …

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18 May 2015

Spheroidal weathering in sandstone

Here’s a nice example of spheroidal weathering in a sandstone, developed using orthogonal jointing and bedding: This is one of many sites I visited Saturday near Bolt, West Virginia, on a field trip with NAGT’s Eastern Section.

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24 March 2015

Martinsburg Formation outcrops in Edinburg Gap

A report from the field: new outcrops of Ordovician-aged turbidites featuring geopetal indicators, fossil content, and a structural overprint imparted during Pangaea’s assembly.

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20 March 2015

Friday fold: flexed turbidites

Spring is almost here! As you get ready for the equinox, enjoy this gentle fold on a Friday: These are turbidites (graywacke and shale) of the late Ordovician Martinsburg Formation, seen in Edinburg Gap, western Massanutten Range, greater Shenandoah Valley, Virginia. Bedding is flexed very slightly here, from moderately-dipping to more steep, and then back to moderate again. Slickensides on the top of some exposed layers indicate the beds shifted …

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27 January 2015

Miette Group gritstone showing scours, mudchip rip-ups, cross-bedding, and dropstones

The coarser strata of the Neoproterozoic Miette Group in the Canadian Rockies of Alberta record changing water current strength over time, and maybe an iceberg or two.

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