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4 September 2020
Friday fold: Home décor
Busy weeks lately; apologies for the minimal bloggery, friends. For this week’s Friday fold, I offer you a view of some of the outdoor decorations at our new house: In the lower basket there is a cut and polished block of Castile Formation rock gypsum + limestone, showing varves that have been folded, apparently by hydration/dehydration volume changes of the gypsum/anyhdrite laminae: This is from the State Line outcrop on …
11 February 2019
When Bugs Were Big, Plants Were Strange, and Tetrapods Stalked the Earth: A Cartoon Prehistory of Life Before Dinosaurs, by Hannah Bonner
It has been a while since I’ve reviewed any kids’ books here, but this one was so good that I just have to tell you about it. My son is now 6 and a half years old, and he’s interested in all sorts of natural history topics. Given that I’m a geologist, he’s probably more Earth-science-focused than the average kid, but my wife is a biologist, so he’s got plenty …
26 January 2018
Friday fold: eastern Andes
This image graces the cover of the new report, Challenges and opportunities for research in tectonics: Understanding deformation and the processes that link Earth systems, from geologic time to human time. A community vision document submitted to the U.S. National Science Foundation: Make it bigger by clicking it The photo is of a landscape in the Eastern Cordillera of the Andes, southern Peru, showing folded Permian carbonates cut by a …
22 December 2016
Dikes at Bunnahabhain
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. A photo, centered on the GigaPanned dike: This is but one of several to be …
4 July 2016
Virtual field trip to Kinkell Braes, Scotland
Walking along the shore east from St. Andrews, Scotland, along the seaside sandstones of Kinkell Braes, you encounter several extraordinary examples of geology. It’s a great place for the next stop on our Grand Tour of the geology of the British Isles. Here’s the scene: The first stop is a giant eurypterid trackway, potentially the largest invertebrate trackway in the world (Whyte, 2005), on the underside of an overhanging sandstone …
1 December 2015
Which way’s up? Check cavity fills.
When snail shells are deposited in a bunch of sediment, they serve as tiny architectural elements, with a “roof” that protects their interiors. Any sediment mixed into the shell’s interior will settle out (more or less horizontally), and then there will be empty space (filled with water, probably) above that. As burial proceeds and diagenesis begins, that pore space may be filled with a mineral deposit, such as sparry calcite. …
10 February 2015
Pisolites in the Tansil Formation, Carlsbad Caverns, New Mexico
Pisolites are large primary concretions that develop in backreef or lagoonal settings such as the Permian Tansil Formation of New Mexico, into which is cut the enormous hole called Carlsbad Caverns.
3 July 2014
Bell Canyon’s Permian submarine landslide
What are these Border to Beltway students up to?… Clearly, they are all immersed in their field notebooks, sketching away. This was in March, in west Texas. There must be something worth drawing at this road cut… A clue can be seen on the wall of rock behind them. There, you can find features such as this: And this: And this: Those are outsized clasts of gray limestone in fine-grained …
20 June 2014
Friday fold: the Castile Formation at the State line outcrop
The Friday fold visits the Permian basin of west Texas. There, the Castile Formation exhibits gorgeous inter- and intra-bed folding.
6 May 2014
McKittrick Canyon, Guadalupe Mountains National Park, Texas
While in West Texas over spring break, the “Border to Beltway” students took a hike up McKittrick Canyon, in Guadalupe Mountains National Park. This is part of the famed Permian reef complex, the deep reservoir of Texas’s rich endowment of oil. Here, the reef comes to the surface. In fact, it pokes up a good bit into the air: Can you see it? If not, let Marcelo, Robin, and Nicole …