Eastern bluebird (and its lunch, a camel cricket) Purple finch (male) At New Year’s, I post my “yard list” here. It’s a list of all the bird species observed in my yard in Fort Valley, Virginia, over the course of the previous calendar year. I have been posting this list every year since I moved … Read more
As noted previously, my colleague Declan De Paor recently retired from Old Dominion University, and I was lucky enough to inherit some of his rock samples. I’ve been making super-high resolution images of the samples ever since. Here’s a particularly striking fold, weathered out differentially. Enjoy exploring it – and have a happy final Friday … Read more
We approach the end of another calendar year, and with it comes my ninth anniversary of beginning to write about geology online. (A year from now will mark a decade of geoblogging for me!) It’s been a rough year, health-wise for my friends and family. Loved ones have suffered strokes, brain cancer, Alzheimer’s, and other … Read more
It’s bonfire season here in the Fort Valley. I live in a forest, and that forest is full of dead and downed wood. Motivated by a desire to (a) reduce forest fire risk and (b) clear out some of the area under the trees for unobstructed recreation, I gather it up and periodically burn it … Read more
Another loose, 3D fold from the north side of Machir Bay, Islay. Wish I could have brought it home to dwell in my lab… Happiest of Fridays to you! The solstice is now past, and the days are getting longer in the northern hemisphere for the next 6 months! Cheers to that!
Yesterday I blogged the stromatolites to be seen in northeastern Islay, south along the shore from the distillery at Bunnahabhain. The sharp-eyed among you may have noticed that in this GigaPan, there’s more going on than merely Neoproterozoic carbonates: Link 1.46 Gpx GigaPan by Callan Bentley There’s also a prominent dolerite dike, weathering out recessively. … Read more
Remember the diamictite I featured here a few weeks ago, from Islay? It was the one that might be a Snowball Earth diamictite. Well, if you follow Snowball Earth science at all, you’ll doubtless be aware that the glaciogenic sediments are characteristically overlain by “cap” carbonates. There’s a stratigraphic successor to the Port Askaig Tillite, … Read more
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.
Over the weekend, I finished an excellent popular summary of genetics, The Gene: An Intimate History, by Siddhartha Mukherjee. It’s an excellent, thoughtful, current tome, that covers everything from Mendel to Darwin to Lysenko to Rosalind Franklin to CRISPR, written in a personal, accessible way. He begins and ends with a trip to India, examining … Read more
Don’t you hate it when plate tectonics ruins a perfectly good fossil? This is a sketch of a belemnite from the Swiss Alps: The thing has been broken into segments, with calcite filling the gaps between the segments. What a bummer! Now we’re going to have a much harder time reconstructing the life habits of … Read more
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
In the past couple of months I listened to the audiobook versions of Ernest Cline’s two novels. They are of a common piece, and so I opt to review them in tandem. There is a feeling I have that I am increasingly at odds with the students I teach in terms of cultural references and … Read more
One fun thing about examining the Port Askaig Tillite in the field is to find odd-shaped exemplars of the unit lying on Islay’s beaches. My favorites were shaped like wands, or antennae, or perhaps the drumsticks freshly detached from a Thanksgiving turkey… a big clast at one end and then a thin septum of the … Read more
The Port Askaig Tillite is a Neoproterozoic diamictite on the eastern shore of Islay (Scotland) that may record a “Snowball Earth” glaciation.
Here’s a look at some of the wild critters that have been visiting my yard this year: [youtube=”https://www.youtube.com/watch?v=hh8muzLOE54″] The video’s organized in alphabetical order, so it starts with bears, and ends with a walking stick insect. See how many you can identify! Plus, here’s a compilation of 125 still photos of black bears from June … Read more
At the birthplace of the term “mylonite,” we can find Friday folds hidden in the foliation.
Scotland was glaciated during the Pleistocene “Ice Ages:” The signatures of glaciation are manifold in a scene like this. Most prominent and easily recognizable is the broad, relatively flat-bottomed U-shaped valley. Now check this one out: That’s a U-turn in a U-shaped valley: the valley is first gouged to the right, then turning around and … Read more