Today the Friday fold comes with copious bonus structures. It’s the first stop we hit on Day 3 of the pre-GSA Minneapolis field trip to examine the structural geology of the subprovince boundaries within the Superior Craton. This particular site showed granitoid dikes that had been deformed during dextral transpression into a variety of structures … Read more
Sorry to be late with this – I think that’s the first time I’ve forgotten to post a Friday fold. Blame it on the tryptophan.
Okay – in spite of numerous distractions (see every other post so far this week), it’s time to return to the pre-GSA Minneapolis structural geology field trip. Our final stop of the second day in the field was a series of folded up mafic metavolcanics. I’ve got some photographs of them. These mafic volcanics were … Read more
At last weekend’s gala banquet to celebrate the 50th anniversary of the William & Mary geology department, I was tickled to see that the centerpiece for each table was a rock of some sort. I spotted Gore Mountain Amphibolite, Baker Mountain Kyanite, brachiopod fossils in limestone, a fossil whale vertebra, a chunk of Aquia Creek … Read more
Today’s fold is an anticline and its neighboring syncline, both exposed along a newly-opened stretch of New Route 55, west of Moorefield, West Virginia. The new Route 55 is a classic porkbarrel boondoggle courtesy of the late Senator Robert Byrd, but doggone if it didn’t open up some lovely new roadcuts. Here’s a stitched image … Read more
This summer, a week or two after our wedding, my wife and I found ourselves in the Canadian Rockies for a pre-honeymoon. Part of our time was spent on a backpacking trip to Floe Lake in Kootenay National Park, British Columbia. On our hike in, we passed this outcrop of Chancellor Slate, a Cambrian aged … Read more
The “Friday fold” is an isoclinal dextrally-asymmetric granitoid vein exposed north of Fort Frances, Ontario. Taken on October 7, 2011, the photo features a centimeter-demarcated pencil for scale. It shows thickened hinges, boudinage of the lower right long limb, and incipient boudinage of the upper left long limb.
The Friday fold is a guest photo by James Edward Bailey, a 5th grade student from Reston, Virginia. It is the anticline shown is known as “the Devil’s Backbone,” located near Marlinton, West Virginia, right on the boundary between the Valley & Ridge province and the Appalachian Plateaus. It clearly shows differential weathering of weaker layers and tougher layers. …Also some lovely fall colors!
Straight-limbed open synform in an organic-rich formation of limited areal extent, featuring some brittle extensional features at the hinge. Kootenay National Park, British Columbia, summer 2011. (The bridge was broken before we got there.)
Whilst at the JMU Field Camp in Ireland this summer, my former student Alan Pitts (author of Not Necessarily Geology), collected this lovely “pocket fold” near Derryclare Lough and brought it back to the States. A couple of weeks ago, after a graduate school advising session at a pub in Fairfax, Alan gifted me the … Read more