Since I showed off the 3D kimberlite intrusion breccias yesterday, I feel as if I owe you some other photos from that lovely exhibit at the IGC. I apologize for the poor quality of these photos – the gorgeous samples were behind glass and brightly lit, which made photography difficult. But the rocks are sooooooooo … Read more
The Friday fold is airborne over the Yukon Territory’s border with the Northwest Territories, high up in Canada’s Mackenzie Mountains. Helicopter for scale.
The Friday fold isn’t real. Instead, this “faux”ld is a sculpture by Spanish artist José Manuel Castro López. Check it out and contemplate some improbable rheology.
It’s Friday! Today’s fold comes to you from Neoproterozoic metasediments on the west side of Islay, at Machir Bay.
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?
What makes an Icelandic cinder cone even better? A coating of fuzzy lichens, perhaps…
For the Friday fold, let’s travel to the northern edge of the Isle of Arran in southwestern Scotland, where near the town of Lochranza, you can find Dalradian metagraywackes that display a lovely suite of folds. There are kink bands, like this one: And this one: And these en echelon kink bands: And these: But … Read more
The Port Askaig Tillite is a Neoproterozoic diamictite on the eastern shore of Islay (Scotland) that may record a “Snowball Earth” glaciation.
At the birthplace of the term “mylonite,” we can find Friday folds hidden in the foliation.
The amount of sea ice on planet Earth is much, much lower than ever recorded at this time of year. Will this anomaly turn out to be a relatively minor “weather” event? Or is this what a sea ice tipping point looks like?
Funzie Bay in eastern Fetlar, Shetland, is the place with a stretched-pebble metaconglomerate that triggered the development of the Flinn Diagram. Join Callan on a pilgrimage of structural geology to this special place.
Here’s the answer to the contest: This is an outcrop on the beach at Funzie Bay, Fetlar, Shetland, U.K. The modern beach sediment is the lightest-colored, rounded cobbles at both the top and bottom of the photo. Poking out in between is a layer of light-gray colluvium (angular fragments) overlain by dark peat, now perhaps … Read more
Have a look at this week’s Friday fold – but be aware that it will be looking back!
What does the sedimentary record of a giant meteorite impact look like? Turns out it is full of tsunami breccia, fine ash, hail-like spherules, and a barium-rich ocean’s crystal precipitates. Join us in the Barberton Greenstone Belt of South Africa to learn more.
Sometimes you find big ideas in small places. Here, a South African chert boulder mimics in miniature fold and thrust belts the world over.
One of my favorite places in Northern Ireland is the east side of the peninsula that hosts the tourist town of Portrush. There, two early schools of geological thought engaged in a battle. The opposing sides were: the Neptunists, who thought all stratified rocks, and in particular basalt, must form from precipitation from the sea, … Read more
Iceland does basalt really, really well. But there are a few non-basaltic igneous rocks to be found there, too. One of them is a green ignimbrite (pyroclastic conglomerate) that crops out in coastal Berufjörður, eastern Iceland. Check it out!
Callan’s colleague Joshua Villalobos won the 2016 Biggs Award. He also makes GigaPans of folds, like these talc-bearing rocks of the Allamoore Formation.
Can a Friday fold be a work of art as well as a source of geologic insight? The answer can be found as you enter Shetland’s Northmavine region.