Here’s one of the cool rocks I saw on my pre-GSA-Charlotte field trip to the Neoacadian Inner Piedmont field trip: the protomylonitic Walker Top Granite (~366 Ma crystallization), which was deformed as the terrane it was intruded into got shoved up and to the west (and perhaps the southwest!). Here’s an animated GIF I made … Read more
A weekend expedition to GigaPan the C&O Canal’s singular Paw Paw Tunnel results in an exposition on Devonian sedimentation, Alleghanian mountain-building, structural geology, and the incision of the Potomac River to produce entrenched meanders.
Callan’s Canadian Rockies field course visits an outcrop of Cambrian slate in Yoho National Park, British Columbia. Folded and boudinaged carbonatite dikes are seen.
A sketch of the Massanutten Synclinorium is presented, made with a Wacom Cintiq stylus/monitor combination.
Callan and his wife hike Cory Pass in Banff National Park, Canada, and encounter some geology, some solitude, and a spectacular landscape.
The Friday fold is a contribution from the Massachusetts Geological Survey. It shows a migmatite with lovely structure. An upcoming (free) field trip to this location will be part of the 2012 Structural Geology and Tectonics Forum: an event readers may be interested in attending
Hand sample of folded limestone strata in West Virginia (presumably Devonian in age). Note the rip-up clasts and large grain size at the base of the sample (to the right in the photo). Note the fine-grained, thin-bedded shale laminations towards the top (left) of the sample, too. Together, they tell a story of decreasing energy … Read more
From the road that keeps on giving: new New Route 55, in West Virginia, west of Moorefield.
This beastie lives in an old quarry in West Virginia, along old Route 55. And from a slightly different perspective… This fold is in Devonian limestones of the Helderberg Group, kinked up probably during the Alleghanian Orogeny (the assembly of Pangea) in the late Paleozoic.
Today, two examples of outcrops that reveal an overprinting relationship between metamorphic cleavage and sedimentary bedding. Both are Devonian in depositional age, from the new stretch of New Route 55 in West Virginia, west of Moorefield. The first is from limestones of the Helderberg Group, and the second is from shale of the Brallier Formation. … Read more