Yesterday, I mentioned climate change visualizer extraordinaire Zack Labe. As delineated then, he’s a PhD student at U.C. – Irvine in the Earth Systems Science department. He’s producing some really excellent #dataviz on climate change. Today, I’d like to share a short exchange I had with Zack about his work. 1) Please give … Read more
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?
Here are three pairs of GIGAmacro images to illustrate a few techniques I’ve used in preparing the samples and the images. The image pairs here illustrate the effects of transparent acrylic coatings, pressure-washing, and post-imaging clean-up in Photoshop. Let’s begin with a meta-ignimbrite of the Catoctin Formation, cut with a rock saw and polished using … Read more
I tried something new this morning, and polled Twitter for their choice of Friday fold: Quick poll – What do you want for the Friday fold? 30 minutes to respond. — Callan Bentley (@callanbentley) November 18, 2016 As of the time of this posting, the first choice, “Lewisian gneiss @ Tarbet” won out with 7 … Read more
I listen to a few podcasts, and I’ve been meaning for a long time to write down some thoughts about them to share, in the same spirit in which I review books, or less frequently movies or television programs. First, a general comment: I really, really like podcasts. This is a medium that is unique … Read more
Now that we’ve examined the geology of the outcrops at Funzie Bay on the island of Fetlar in northeast Shetland, let’s stroll along two beaches. Here we have cobbles from Funzie Beach and a small beach eroded from serpentenite and metaharzburgite of the island’s ophiolite complex. Compare. Contrast. Rejoice. Link GigaPan by Callan Bentley Link … Read more
It’s been a week since Donald Trump defeated Hillary Clinton in the race for the President of the United States. I’ve been processing the news, and I’m not happy about it. I’ve been on “radio silence” for a week, mourning, ruminating, fretting. From my perspective, this is one of the most disturbing developments in the … Read more
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
Lens cap for scale. Correctly tell me what’s going on here, and you get A Big Prize!
I’ve let my subscription to the New Yorker lapse, but before I did, I was pleased to read each week its diverse suite of authors on a diverse suite of topics. This has been a source of surprising delight on several occasions, and has allowed me to discover not only topics I never thought to … Read more
Happy Friday. Thank goodness it’s the last one before this horrible election season finally concludes. Let’s celebrate with two cobbles from the beach at Papil Water, Fetlar, Shetland. They show small-scale folds in metasedimentary and metavolcanic rocks of Ordovician or Silurian age, part of the ophiolite complex that makes up most of Fetlar. Each is … Read more
We’ve taken a look already at an exemplary tombolo from Shetland. Today, I’m dialing up the tombolosity of the blog with a Triple Feature: Click to make much larger (8000 pixels wide) If you look closely here, you’ll see that only the rightmost bar fully connects the two islands. It’s the only true tombolo, sensu … Read more
In Shenandoah National Park, astride Virginia’s Blue Ridge, feeder dikes of Catoctin Formation (meta-)basalt cut across the Grenvillian-aged granitoid basement. Due to their mafic composition and columnar jointing, these feeder dikes generally weather more rapidly than their host rocks. I led a field trip in the park on Thursday for my son’s school, and my … 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.
Erik Klemetti posted today at Eruptions about komatiite, which is apropos, considering I just finished imaging some samples of that ultramafic volcanic rock. Have a look at three samples from Barberton Greenstone Belt here, each from the 3.27 Ga Weltevreden Formation: Link GigaPan by Callan Bentley Link GigaPan by Callan Bentley Link GigaPan by Callan … Read 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.
At the Volcano Museum in Stykkishólmur, I learned that Iceland has fossils. Specifically, they have a display of bivalve (clam) fossils there, and when I asked where to find them, I was directed to a point further east on the Snæfellsnes Peninsula. The next day, I set off to find them. Here was what I … Read more
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