You are browsing the archive for 2016 November.
30 November 2016
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 finer-grained matrix to hang on to: Here’s an example: The shape results from differential weathering …
29 November 2016
The Port Askaig Tillite is a Neoproterozoic diamictite on the eastern shore of Islay (Scotland) that may record a “Snowball Earth” glaciation.
28 November 2016
Here’s a look at some of the wild critters that have been visiting my yard this year: 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 of 2015:
25 November 2016
At the birthplace of the term “mylonite,” we can find Friday folds hidden in the foliation.
24 November 2016
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 heading in almost the reverse direction: Good things these things flow so slow, otherwise that …
23 November 2016
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 Mountain Beltway readers a sense of your background, leading up to what you’re working on …
22 November 2016
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?
21 November 2016
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 a handheld grinding wheel with diamond grit pads, and then with one of the two …
18 November 2016
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 / 10 votes. The people have spoken, and this time I like the result of …
17 November 2016
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 (aside from radio) in its ability to get you to think while you’re doing something …