Callan Bentley I’m very nearly delinquent on posting the Friday fold… Here you go – a Google Earth view of a differentially-weathered fold partly above and partly below sea level in Chilean Patagonia, south of Puerto Natales: They call it Isla Escarpada. Awesome. Here’s a Google Maps link if you want to explore it yourself. Happy Friday!
A report from the field: new outcrops of Ordovician-aged turbidites featuring geopetal indicators, fossil content, and a structural overprint imparted during Pangaea’s assembly.
Spring is almost here! As you get ready for the equinox, enjoy this gentle fold on a Friday: These are turbidites (graywacke and shale) of the late Ordovician Martinsburg Formation, seen in Edinburg Gap, western Massanutten Range, greater Shenandoah Valley, Virginia. Bedding is flexed very slightly here, from moderately-dipping to more steep, and then back … Read more
A morning’s field trip yields an outcrop of excellent Zoophycos trace fossils in southern Fort Valley, Virginia.
A quick virtual field trip to the Neoproterozoic glaciogenic sedimentary rocks from the central Virginia Blue Ridge province: Can you feel the chill of Snowball Earth?
Reader Mike Pendergrass contributes this Friday’s fold: I found your blog a couple years ago and I share your love of structural geology. I did my Master’s Thesis while at Northern Arizona University in the early 80’s and mapped an area on the Mazatzal Mountains of central Arizona. The Mazatzals in my field area contain … Read more
Callan reviews 11 books he’s read in the past 11 months, some having to do with geology, many with the intellectual heritage of scientific insight, a few about history, two biographies, and some about random things.
At the Spiral Tunnels overlook on the Trans-Canada Highway, you can look at trains. Or, you can check out some lovely trace fossils in boulders which divide the viewing area from the highway: These are in the Gog Formation, a Cambrian-aged quartz arenite, mostly fused to quartzite nowadays… I know which subject I would choose … Read more
Back at the beginning of January, I asked for help on Twitter for Friday fold fodder. Here are three responses I got: @callanbentley one of my favorites from South Georgia Island. Have more on the laptop. pic.twitter.com/UaRtxM77Vm — John Van Hoesen (@Taconic_Musings) January 8, 2015 @callanbentley 2 folds from my SC Inner Piedmont MS thesis … Read more
My student Robin has been busy cranking out great new macro GigaPans. Check out a few of these new examples: link link link link link link link link
Today is the 10-year-anniversary of the day I adopted Lola the cat. She’s been a faithful companion for a quarter of my life! Here’s the day it happened, as recorded in my 2005 calendar: Look at this historical document – Titanic opens; Malcolm Gladwell giving a talk; I was still doing woodcut block printing – … Read more
Another one from Kim: Kim says: Pygmatic folds in the Precambrian Irving Formation. I think this is 1.7 Ga deformation, late in the Yavapai orogeny, which added various arcs in Colorado to North America. Good place to think about strain ellipses in progressive deformation. Zooming in on the best part, and dialing up the contrast … Read more
Pisolites are large primary concretions that develop in backreef or lagoonal settings such as the Permian Tansil Formation of New Mexico, into which is cut the enormous hole called Carlsbad Caverns.
Kim Hannula shares a fold today: Kim says: The rocks folded here mostly the Devonian Ouray Limestone. There’s a fault through the outcrop, and another fault to the left of the photo. Regionally, the faults are mapped as normal faults, mostly with the east (right in photo) side down. Locally, that’s not what I see … Read more
The coarser strata of the Neoproterozoic Miette Group in the Canadian Rockies of Alberta record changing water current strength over time, and maybe an iceberg or two.
Elizabeth Kosters contributed this week’s Friday fold: It’s from Rainy Cove, Nova Scotia, Canada. Click through to read Elizabeth’s post on the site. Happy Friday!
One last post from my September trip to Greece. Here’s a look north along the inside wall of the central caldera of Santorini, taken from the deck of the Santos Winery. It’s not hard to imagine the volcanic edifice that filled the space to the left (west) prior to The Big One.
Three images, working our way in from outcrop setting to hand sample: link link link These fine red sandstones are the Silurian-aged Bloomsburg Formation, as it crops out in Fort Valley, Virginia. What would we see if we kept zooming in? …Stay tuned…
As a follow-up to my post about the geology of the Acropolis klippe in Athens, Greece, and in the spirit of my post on the building stones of the Haghia Sophia in İstabul, Turkey, let’s turn our attention today to the various rocks that ancient Greeks used to construct the buildings of the Acropolis, such … Read more