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You are browsing the archive for concretions Archives - AGU Blogosphere.

25 February 2017

Concretions in the Millboro Formation, Fort Valley

Some enormous concretions are encountered in a shale quarry in the central Fort Valley. Concretions like these are typical of the Devonian-aged Millboro Formation.

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7 June 2016

Variably-cemented conglomerate – a virtual sample

Here’s another example of a visualization combination that leverages the advantages of the GIGAmacro system with the 3D ‘virtual sample’ perspective of the Sketchfab-hosted model: the same sample presented in both formats. In this case, it’s a lovely example of a conglomerate that I found in our lab at NOVA, showing variations in the level of cementation around a central ‘nucleus’. [gigapan id=”187640″] Link GIGAmacro by Callan Bentley [sketchfab id=”6f1cb165f5414b878ad733f22a256eaa” …

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31 March 2016

This week’s batch of 3D models

Anorthosite with lovely garnet reaction rims, a spherical hematite concretion, and some sweet breccia. Check them out and explore! [sketchfab id=”4453575da99743679a083363a0429b63″ start=”0″ spin=”” controls=”0″] [sketchfab id=”4333df612167415a8e216cef25e8cac6″ start=”0″ spin=”” controls=”0″] [sketchfab id=”cb58f446782d4736b699127884b46d16″ start=”0″ spin=”” controls=”0″]

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28 July 2015

Millboro Formation shale in outcrop and in hand sample

Another site from the GMU sedimentology field trip in April: An outcrop on Route 33 in Brandywine, West Virginia, showing the Millboro Formation. It’s mostly shale, with some intriguing sandstones, too. There are fossils and diagenetic carbonate nodules (concretions). Here’s the outcrop, the largest GigaPan I’ve taken so far (7.9 billion pixels): [gigapan id=”171447″] link The shale itself looks… like shale. It’s fine-grained, and dark (high carbon content, suggesting low …

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20 September 2011

Giant City State Park, Illinois

Giant City State Park is a patch of protected forest south of Carbondale, Illinois, where there are some pretty cool exposures of Pennsylvanian-aged Makanda Sandstone. Here’s a typical look at one: Notice the deep chasm on the right. This leads, maze-like, to other flat-bottomed and vertically-walled canyons: The orthogonal joint sets produces some nice tall, cliff-like vertical exposures that reveal the history of these rocks in several stages: deposition by …

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