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You are browsing the archive for stromatolites Archives - Mountain Beltway.

9 August 2017

A suite of new 3D models

A showcase of five new 3D digital models of awesome rock samples and outcrops, produced using Agisoft Photoscan.



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21 December 2016

Stromatolites of Bunnahabhain

Remember the diamictite I featured here a few weeks ago, from Islay? It was the one that might be a Snowball Earth diamictite. Well, if you follow Snowball Earth science at all, you’ll doubtless be aware that the glaciogenic sediments are characteristically overlain by “cap” carbonates. There’s a stratigraphic successor to the Port Askaig Tillite, too – it’s called the Bonahaven Dolomite. Unlike what you might expect for a cap …



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1 September 2016

Archean microbial mats in the news and in GigaPan

The news yesterday of 3.7 Ga stromatolites in Greenland prompts a closer look at 3.22 Ga microbially-induced sedimentary structures in the Barberton Greenstone Belt’s Moodies group sandstones.



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2 August 2016

Oldest fossils in the UK: M.I.S.S. in Stoer Group, Scotland

This is the Split Rock at Clachtoll, on the shore of the North-West Highlands of Scotland. You’re looking out to sea, over the Minch. It’s the site that graces the cover of the excellent book A Geological Excursion Guide to the North-West Highlands of Scotland, by Kathryn Goodenough and Marten Krabbendam. “Clach toll” apparently means “Split rock” — Go figure. The Split Rock is an easy landmark to steer toward …



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28 June 2016

“Dunbar marble” at Barns Ness, Scotland

Thanks to the website ScottishGeology.com, run by Angus Miller, I learned of Barns Ness, a Mississippian-aged limestone fossil site on the shore not far from where we are staying at Dunbar. We ventured out there on Saturday afternoon, in search of fossils. The presence of the Dunbar Cemenet Works nearby is an indication that this is the most extensive limestone outcrop in central Scotland. I set my field assistant loose …



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10 June 2016

Green River Formation stromatolite – a virtual sample

Today concludes a weeklong run of  virtual samples. For the past five days, I’ve been presenting examples 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. Today, we finish up with a stromatolite from the hypersaline Wilkins Creek member of the Eocene-aged Green River Formation of southwestern Wyoming: Link GIGAmacro …



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29 March 2016

Four new GIGAmacro images

Here are a few new images I’ve been working on with my home-based Magnify2 imaging system from GIGAmacro. Archean basement complex gneiss from the Gallatin Range of Montana: Link (If this looks familiar, that’s because one of the samples I imaged with the Photoscan 3D modeling technique and published on Sketchfab the week before last.) Banded iron formation from Minnesota with ooids and stromatolites: Link Intrusion breccia: Link Blue Ridge …



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9 December 2015

Thrombolites of the Great Salt Lake, Utah

I saw mention of thrombolites exposed along the shore of Antelope Island in the Great Salt Lake the other day in my Facebook feed; because the description cited a professor at Westminster College in Salt Lake City, I prompted my friend and colleague Tiffany Rivera, also a geology professor at Westminster, to go check it out and get me some bloggable photos. As it turned out, she already had – …



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30 July 2015

Stromatolites of the Helena Formation, Grinnell Glacier Cirque, Montana

My favorite place to have lunch in Montana is at the Grinnell Glacier cirque in Glacier National Park. This is the dining room table: You’re looking at a bedding-plane-parallel exposure of Mesoproterozoic stromatolites here. Every few years, I’m lucky enough to hike up there with motivated students and share food atop this unparalleled view into the shallow seas of more than a billion years ago. Stromatolites are sedimentary structures that …



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8 January 2015

Stromatolite at the Strasburg Museum

The other fossil I saw at the eclectic and haphazardly-curated Strasburg Museum was this stromatolite. Top view: Side view: Probably this comes from the Cambrian-aged Conococheague Formation, although the Beekmantown Formation (early Ordovician) is another possibility.



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