Halite casts (hoppers) from the Wills Creek / Tonoloway Formations in West Virginia

While we’re out on Corridor H, let me show you some new halite casts I found (either the Wills Creek Formation or the Tonoloway Formation): Salt casts are among my favorite primary structures. They speak very specifically to hypersaline depositional conditions.

Stylolite from the Helderberg Group, exposed on Corridor H

While out on the Corridor H field trip last week before the heavy snow, I found this squeal-inducingly-lovely example of a stylolite in Helderberg Group limestones (Devonian passive margin carbonates): The stylolite is a pressure-solution surface, made especially apparent in this example because of the starkly different grain sizes and colors on either side of … Read more

Foreknobs Formation: a new outcrop with a possible submarine mass transport deposit

Today, we continue with the story of the field trip I took last week out to Corridor H, the new superhighway in West Virginia that is practically unused, and decorated with multistory roadcuts of spectacular Valley and Ridge sedimentary sequences, and their attendant structures. From the putative Hampshire Formation exposures with their uncharacteristic marine incursion … Read more

A marine incursion in the Hampshire Formation?

I went out last Tuesday to Corridor H, the exemplary new highway cutting through the Valley and Ridge province of eastern West Virginia. Joining me was former student Alan Pitts, a devotee of Corridor H from way back in the early days when we just called it “New Route 55.” The boondoggle highway is now … Read more

Halite casts from Tonoloway Formation under the GIGAmacro lens

The work of team M.A.G.I.C. continues. This is a lovely sample quartet of salt cast samples from Silurian-aged Tonoloway Formation limestone. I collected these samples on Corridor H’s newly-opened section west of Moorefield, West Virginia, last spring. The big one at the bottom was collected by my friend Leigh Henry, who graciously loaned it to … Read more

Slip-shine

When are sedimentary layers also faults? …When the slab-like layers slip over and under one another during the act of folding. Structures traditionally confined to faults show up on the bedding plane in these circumstances. Callan shares a shiny example from West Virginia in the form of an animated GIF.

Friday fold: a tortured tempestite

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

Beautiful rust

Rust swirls on shale fragment, new New Route 55, Valley & Ridge province of West Virginia. I’m not sure if I can call this “Liesegang banding,” since it’s just on the joint surface (two-dimensional) rather than permeating the rock in a three-dimensional blob. Anyhow… It’s pretty.

Sed or meta? Yes.

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

Brallier cross-beds

More evidence of currents in the Devonian deep… Primary structures that give us clues, preserved in a place where preservation over 360 million years isn’t necessarily guaranteed. As you might expect, this turbidity currents roared in from the east, where the mountains were rising, and generating a fair bit of sand and mud, during the … Read more

Friday fold: one from Romney (West Virginia)

Last weekend, my wife and I joined friends for a weekend of cross-country skiing in the wonderful Canaan Valley of West Virginia. On the way back, between the towns of Burlington and Romney, West Virginia, I saw this folded shale on the north side of Route 50: You can click on that panorama to make … Read more