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A chip off the ol’ charnockite
We visited the Philip Carter Winery this weekend with family. Baxter and I were pleased to see outcrops of charnockite scattered over the property (located in the middle of the Blue Ridge geologic...
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The Great Unconformity in the Franklin Mountains
Good morning! Let’s take a walk up the east side of the Franklin Mountains, north of El Paso, Texas, to walk across the Great Unconformity. The basement rock exposed here is the Red Bluff Granite, a...
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Stromatolite from near Crypt Lake
Greetings from the field… here’s a scene I contemplated yesterday…
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Field work on the Grinnell Formation at Red Rock Canyon, Waterton Lakes...
While in Waterton Lakes National Park, Alberta, my field class visited beautiful Red Rock Canyon to practice our field observation skills. This is a deep gorge cut into red and green argillite of the...
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Friday fold: Miette slate, Alberta
Previously I’ve featured a road cut at the intersection of the Trans-Canada Highway and the Icefields Parkway as the Friday fold. Here are some other look at cool features to be seen at this outcrop,...
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Friday fold: a surging rippled whale of Grinnell Formation
Along Going-to-the-Sun Road in Glacier National Park, you can see this outcrop of Mesoproterozoic Grinnell Formation quartzite (former quartz sandstone) and red argillite (oxidized mud rock). These...
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Miette Group gritstone showing scours, mudchip rip-ups, cross-bedding, and...
Previously on Mountain Beltway, we’ve examined the Neoproterozoic Miette Group of the Canadian Rockies by looking at its finer-grained strata. Today, It’s going to get a bit coarser. There’s a nice...
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Friday fold: Ptygmatic Irving Fm., Colorado
Another one from Kim: Kim says: Pygmatic folds in the Precambrian Irving Formation. I think this is 1.7 Ga deformation, late in the Yavapai orogeny, which added various arcs in Colorado to North...
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Friday fold: Mazatzal Orogeny, Arizona
Reader Mike Pendergrass contributes this Friday’s fold: I found your blog a couple years ago and I share your love of structural geology. I did my Master’s Thesis while at Northern Arizona University...
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Mechum River Formation, near Batesville, VA
Previously on this blog, I’ve mentioned the diamictites of the Konnarock Formation, the Rockfish Conglomerate, and the Fauquier Formation. There is another probable glaciogenic unit in the Virginia...
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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...
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Student guest post: the Belt Supergroup in Glacier National Park
As longtime readers know, late summer is when my Rockies students submit their final projects – web-based explanations of key geologic sites they examined during the trip. Today, I offer you a guest...
View ArticleAnother trio of 3D models
Here are three more of my Photoscan-generated, Sketchfab-hosted 3D models of rock samples: Mud cracks in Tonoloway Formation tidal flat carbonates, Corridor H, West Virginia: Diorite from the eastern...
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Cooling columns of the Catoctin Formation, Indian Run Overlook, Shenandoah...
It’s National Park Week, which means free entrance to our nation’s many wonderful national parks. My local park is Shenandoah National Park, astride the Blue Ridge one mountain range over from my...
View ArticleCleavage refraction in Konnarock Fm. rhythmites – a virtual sample
Here’s 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...
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Friday fold: The walls of Scalloway Castle
When in Shetland, one of my first stops was the museum in Scalloway, and one of the ancillary benefits of visiting there is the castle next door: Scalloway Castle includes building stones derived from...
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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...
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Northwest Highlands unconformities (1 of 3): Sub-Stoer Group
There are three major unconformities in the North-West Highlands of Scotland. I’ll be profiling each over the coming weeks. Schematically, this is their relationship in cross-section: The oldest of...
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Northwest Highlands unconformities (2 of 3): Sub-Torridonian Group
Let’s now profile the next unconformity in the sequence of pulses of erosion and deposition recorded in the North-West Highlands of Scotland. For a reminder, here’s a cartoon cross-section through the...
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Northwest Highlands unconformities (3 of 3): Sub-Ardvreck
It’s time to cover the third and final unconformity I observed this summer in the North-West Highlands of Scotland: the unconformity between the Neoproterozoic Torridonian Group below and the Cambrian...
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