Stac Fada
The evidence for a meteorite impact origin for the Stoer Group’s Stac Fada member seems to stack up. Engage in a virtual field investigation on Mountain Beltway.
gigapan
Virtual owl pellet
Owls are nocturnal birds of prey that eat rodents and grasshoppers, digest the good stuff, and cough up the rest in compressed “pellets” of fur, bone, and chitinous exoskeleton. I found an owl pellet in my yard a few weeks ago, and imaged it using my GIGAmacro Magnify2. I rotated it around to get multiple … Read more
P-sol in a conglomerate countertop slab
A hardware parking lot in rural Virginia showcases an elegant slab of pressure-solution induced compaction of a conglomerate.
Gabion
Do you remember the blog post four years ago about documenting the doomed outcrops at Scientists’ Cliffs, Maryland? It was the site of gorgeous Miocene fossil exposures in the Calvert Formation. Here’s what the site looks like now: Photo by Peter Vogt That ugly thing at the base of the cliff is a gabion, … Read more
Basaltic strata, faulting, and glaciation in western Iceland
Today, let’s journey to Iceland, to a bit northwest of Reykjavík. This is a view from the top of the Grábrók cinder cone, across the valley to the east. With very few exceptions, Iceland is a big pile of basalt, and that shows through in the walls of this valley, which display a stack of … Read more
Shear zones in Scottish gabbros
A quest to visit the “first shear zones” described in the scientific literature leads to an alternate location, and some GIGAmacro images of samples from the real, original spot.
Friday fold: Smaull Graywacke at Saligo Bay, Islay
On the western coast of Islay, Saligo Bay showcases turbidites of the Neoproterozoic Colonsay Group. The Smaull Graywacke shows Caledonian (late Ordovician) folding and cleavage superimposed on world-class graded bedding. There’s also a nice dolerite dike to examine.
Friday fold: one from the archive
As noted previously, my colleague Declan De Paor recently retired from Old Dominion University, and I was lucky enough to inherit some of his rock samples. I’ve been making super-high resolution images of the samples ever since. Here’s a particularly striking fold, weathered out differentially. Enjoy exploring it – and have a happy final Friday … Read more
Silent samples, holey samples
Two very different samples tell stories that are full of holes. What’s going on with this weathered sandstone? What’s going on with this fossil scallop shell?
Islay’s Port Askaig tillite
The Port Askaig Tillite is a Neoproterozoic diamictite on the eastern shore of Islay (Scotland) that may record a “Snowball Earth” glaciation.