You are browsing the archive for January 2019 - Mountain Beltway.

29 January 2019

The Parallel Roads of Glen Roy

What can we learn from Scotland’s Parallel Roads of Glen Roy?


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25 January 2019

Friday folds: more Marli Miller

Four Friday folds from Marli Miller’s online photo archive of geological images.


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18 January 2019

Friday fold: Saluda Dam, South Carolina

Scott White (@SeafloorScott) of the University of South Carolina pitched in with today’s Friday fold: Click to enlarge This shows a section of high grade gneiss in the spillway of the Saluda Dam in Columbia, South Carolina. Zooming in there, you can see a nice fold hinge on the left edge: Although I don’t know the precise location of this outcrop, I did a bit of internet sleuthing… According to …


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15 January 2019

Easing of selective pressure on Opuntia cacti in the Galapagos Islands

A cactus you can pet with your bare hand? Turns out it can tell you something about whether that island contains any land iguanas. A case study in the easing of natural selective pressure.


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14 January 2019

A tale of three iguanas

As noted last week, I spent the week spanning New Year’s Eve in the enchanted isles of the Galapagos. The previous week (over Christmas) my family and I were in coastal Ecuador. I saw a total of three species of iguanas in the two locations, and they offer a neat little story of evolution. Let’s take a look. First, let’s introduce the key players: The green iguana,┬áIguana iguana (coastal Ecuador, …


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11 January 2019

Friday fold: more from Utah

For the final Friday fold of 2018, we return to Utah’s Slate Canyon, where “Mountain Beltway” reader Octavia Sawyer shares an anticline with parasitic folds shaped like “sea serpents.”


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8 January 2019

Geology of the Galapagos Islands

Dozens of delectable geological images from the Galapagos Islands, showing fluid basalt flows and violent pyroclastic deposits along with many primary volcanic features (and a bit of sedimentology thrown in for good measure).


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1 January 2019

2018 Yard List

New year’s day is the time I tally up and report the bird species seen in my yard on the forested slope of Massanutten Mountain in Shenandoah County, Virginia. This is my seventh such annual list. Here are the previous iterations: 2012 (39 species) 2013 (51 species) 2014 (58 species) 2015 (65 species) 2016 (59 species) 2017 (56 species) It’s been a good year. Two new “seen for the first …


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