Remember the Virginia Geological Field Conference from back in October? Well here’s a folded quartz vein we observed along a small shear zone in the Blue Ridge basement complex. There are two views of it, from approximately perpendicular points of view: These rocks are Mesoproterozoic, but the vein would obviously be younger than that, and … Read more
What does it mean for a vein to be “quantankerous?” Well, to start with, it’s quartz. Second, it has to be disagreeable or cantankerous. This vein, seen in meta-arkose of the Catoctin Formation near the summit of the Blue Ridge at Rockfish Gap (not Afton Mountain), is such a quantankerous individual: You’ll notice its “S” … Read more
The 2017 Virginia Geological Field Conference had a heavy arkose infusion. Meet some of these feldspar-rich Neoproterozoic sediments of the Lynchburg Group.
My son and I hiked Compton Peak in Shenandoah National Park this morning, and saw these two lovely examples of xenoliths. The example above is small, but it shows clearly the difference between the coarse, felsic basement rock (Mesoproterozoic granitoid, comprising the xenolith) and the surrounding fine-grained dark green metabasalt of the Catoctin Formation (Neoproterozoic). … Read more
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 formats. In this case, it’s a lovely example of cleavage refraction going from meta-clay-shale (now ‘slate’) through a graded bed of fine sand and silt. [gigapan id=”187755″] … Read more
An inaugural visit to an outcrop in Shenandoah National Park reveals the signature of lava flows ~600 million years old.
Here are a few new images I’ve been working on with my home-based Magnify2 imaging system from GIGAmacro. Strophomenid brachiopods from Mississippian Mauch Chunk Formation, West Virginia: [gigapan id=”185738″] Link Boninite from New Caledonia: [gigapan id=”185707″] Link Lepidodendron scale-tree bark from Poland: [gigapan id=”185689″] Link Potassium feldspar crystal, from a pegmatite: [gigapan id=”185688″] Link Catoctin … Read more
Anorthosite with lovely garnet reaction rims, a spherical hematite concretion, and some sweet breccia. Check them out and explore!
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: [gigapan id=”185543″] 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 … Read more
The geology east of Harpers Ferry, West Virginia, is cool. It’s Blue Ridge rocks, from basement to the cover sequence, tilted to the west and broken and repeated by the Short Hill Fault. Here’s a look at a detail of the Geology of the Harpers Ferry quadrangle by Southworth and Brezinski (1996). So there’s a … Read more