7 May 2021
Last weekend, I went to get my second vaccination, and because of the ridiculous quirks of the way the vaccination campaign is (dis)organized, I had to travel to Lynchburg, Virginia, to get the shot. An extra two hours on the road (roundtrip) may sound like a pain, but it was ameliorated by getting to see some cool outcrop along the way.
This is in Riveredge Park in Madison Heights, Virginia, directly across the James River from downtown Lynchburg:
The rock here is Neoproterozoic Lynchburg Group metasediments that were folded and faulted during Appalachian mountain-building. The layering you see is primary sedimentary bedding, and it serves as strain markers for westward-verging asymmetric folds (and tectonic cleavage in the muddier layers).
In the upper right (east), the outcrop features sandy layers that show off more open folding:
Look for the variation in dip across this field of view: essentially vertical in the upper left, moderately left-dipping in the center, and approaching horizontal at the lower right edge:
Small-scale parasitic folds and cleavage are particularly well expressed at this spot:
(I had teased that site on Twitter earlier this week.) Another example of the little crenulations:
Rock fall aficionados will also appreciate this outcrop for its instability. There’s a skin of soil and vegetation stretching across a rock-free chasm at the top of the cliff, and a pile of debris at the bottom. Access to the cliff is fenced off with a “no trespassing” sign posted; a reasonable precaution it seems to me. Still, the debris run-out reached to the edge of the parking area and had broken through one of the fence cross-beams, so maybe they should go further.
It’s also interesting to see the various processes of weathering playing out here. The outcrop was much prettier just two years ago, as this Google Maps Streetview capture shows. Since then, it’s rotted and painted itself with iron oxides and what appears to be travertine:
There are even some little “stalactites” building downward off some of the overhangs:
I collected one sample there; which I intend to turn into a 3D model – Maybe in time for next week’s Friday fold…?
Happy Friday, and Happy End-of-the-Spring-Semester to those who observe!
16 April 2021
Reader Carl Brink laments the lack of robust recent Friday folds, and he’s decided to do something about it!
From Colorado’s Front Range, he sends this image of an intensely folded granite dikelet within Proterozoic biotite schist:
That’s intense. Ptygmatic, sure, but the butterfly-like sense of symmetry to it reminds me of a Rorschach blot.
What a gorgeous fold. Thank you, Carl!
26 March 2021
It’s Friday, and it’s been a few Fridays since I offered you a fold. Let me make up for that with five Friday folds today, all from the incredible collection of free 3D models by Sara Carena on Sketchfab.
Sara is a senior scientist/lecturer in Geology at Ludwig-Maximilians University in Munich.
Absolutely super models of absolutely super folded rocks. Well done, Sara! Viewing these should get everyone’s weekend off on the right foot!
20 February 2021
Jess Phoenix first came onto my radar when she ran for Congress in 2018. Since that time, and thanks to Twitter’s ability to connect geologists, Jess and I co-hosted a 2019 Pardee Symposium on geoscience communication at the GSA annual meeting in Phoenix, Arizona. Jess stepped in at the last minute to cover for Iain Stewart, who was unable to be there due to a family emergency. Like Iain, Jess has been the face of geoscience on television programs, an advocate for for science-based policy and the excitement that a geology-infused perspective on the world brings to one’s life. In Ms. Adventure, her first book, Jess recounts the experiences that made her choose geology as a career, and formative lessons on volcanoes, research cruises, and television. It’s a fun read, more of a memoir than a geoscience text, but there are bite-sized explanations for volcanological phenomena here and there. Several standout sections detail the rationale for certain geoscientific practices. For instance, in a chapter about facing down a cartel to retrieve her beloved rock hammer, she writes, “To a field geologist, a good rock hammer is indispensable. Seeing the inside of rocks, the parts free from the ravages of weather and time, is how we discover their true nature. Since we don’t have x-ray vision, the rock hammer makes understanding the heart of the those very solid objects possible. I often joked that if I couldn’t fix a problem with my rock hammer, it couldn’t be fixed.” The book tracks Jess from Death Valley to Hawaii to Ecuador, Mexico, and the Explorers Club in New York City. I think this would be a great book to gift to an adventurous teen with an orientation toward nature. As she gets into and out of hot water, Jess explains her thinking and rationale. I think it would be a good guide for a young person keen to participated in the world and in need of role models to emulate. Though Jess didn’t win her political campaign, she’s still out there today, working hard to expand everyone’s access to understanding their home planet. This takes many forms: expeditions for student researchers via her nonprofit Blueprint Earth, her prominent advocacy on social media and in periodicals and journals, television appearances, and now: a book!
16 February 2021
Stereotypically, I think of anthropologists as scholars who head off into years-long sojourns embedded with indigenous peoples, learning their cultures, practices, and insights. Vincent Ialenti has shown me that modern anthropologists can study other groups too. Ialenti’s population of interest is a modern group of European geoscientists, nuclear engineers, and planners. Together, they are charged with planning for the integrity of a Finnish nuclear waste repository. But studying this group, called “the Safety Case,” has led the author into a non-traditional direction. His dissertation research inspired him, for his subjects thought about time differently from “normal” people. Geologists won’t find this shocking, to think in Deep Time – both backward and forward over millions of years, but it appears to have been profoundly insightful to Ialenti. He reworked his anthropological documentation into an unusual book that simultaneously attempts to report on the nitty-gritty of a very specialized academic study but also spin off grand lessons for humanity at large. I picked it up for the latter, but was willing to indulge in the former. I felt the book was at its strongest when it articulated a vision for the future where Deep Time thinking is integrated into educational curriculum, if not into the wider culture, but the academic anthropological descriptions of Finnish bureaucrats didn’t engage me as much as Ialenti appears to think it should. Similarly, the end-of-chapter exercises in practicing Deep Time thinking (which he calls “reckonings”) didn’t feel especially novel to me, but I am a geologist who is quite comfortable toggling back in time to the Cambrian, or forward 10 million years into the future. I’m probably not the target audience because I’m already sold on the main conclusion, and I would be curious to hear whether novices find these activities mind-expanding. I agree with Ialenti’s premise: that our species and our world benefit if we think about the very, very long-term consequences of our actions or inactions. Replacing short-sightedness with looooooooooooong-sightedness is an unalloyed benefit, I’d argue too. How can we be responsible ancestors to the future of our species; the future of life? Deep Time Reckoning comes at this question from a unique direction, and offers clear guidance for our common future.
14 February 2021
Elizabeth Kolbert’s third book is now out! Under a White Sky is “a book about people trying to solve problems created by people trying to solve problems.” These problems are environmental problems – they are instances of nature becoming less natural. As humans build cities and plant crops and make waste, we alter the world we live on, the ecology we live within. In Kolbert’s previous book, the Pulitzer Prize-winning The Sixth Extinction, she examined ongoing crises with ocean acidification, invasive species, and novel diseases, all set against the geologic context of extinction, and the causes of mass extinction trauma in Earth’s deep history. Under a White Sky continues that work, but the direction of Kolbert’s gaze is different. The new book’s attention is focused instead on attempts to intentionally alter the future. From genetic engineering to pest control and nurturing of endangered species to carbon capture and solar radiation management, she examines strategies being taken by some humans in our world to try and make the planet of tomorrow better than it would otherwise be. Like all of her writing, the new book strikes a readable balance of background, reportorial anecdote, interviews with leading thinkers, and clever wordplay. It’s a delight to read, informative across a wide range of anthropogenic environmental issues and various attempts at solutions. This is a book about the Chicago River, the Devil’s Hole pupfish, the Greenland ice sheet, and calcite filling basaltic amygdules. It’s about coral spawning and gene drives and forest albedo and volcanic eruptions, and how all of these things are case studies in the human control of nature, in the continued existence of human civilization on this planet, and the other species with which we will be sharing our altered planet. Recommended.
5 February 2021
Here’s a good sample, another one I inherited from Declan de Paor when he retired from Old Dominion University. It’s an interesting sample – I guess I’d call it a graphitic clay shale, but it’s surprisingly lightweight, so I’m not super confident that’s right. The bedding surfaces are glossy and slick, indicating some flexural slip between the layers. In terms of composition: It’s too beautiful to cut up and make a thin section, and of course I can’t ask Declan any more, so its 3D beauty will just have to speak for itself.
29 January 2021
I have two Friday folds for you today, both by geovisualizers who contributed to the 2019 Geological Society of America Pardee Symposium on Geoscience Communication in Phoenix, Arizona:
I love Emma’s art. What other lovely folds have you seen in fine art?
The second is a luminous photomicrograph by Bernardo Cesare, showing a substantial garnet porphyroblast (right) in a tightly folded graphitic schist (the folded bit) from the Tauern Window of the eastern Alps.
Nobody makes thin section imagery like Bernardo does. There’s also a paper to be cited here: In this case, it’s one making the point that garnet can be tetragonal rather than cubic.
I look back on that Pardee art show with great pride – we really brought together some of the most amazing geovisualizers in one place for a glorious day. It’s so nice to see the contributors are continuing to churn out amazing images into 2021….
Peace be with you, friends. Happy Friday.
20 January 2021
When hiking recently in my neighborhood, I saw this gleaming apparition appear in an eroded gully in a dirt road:
Those multicolored stripes are varying compositions in a zone of ultramylonite: ductilely-sheared-out rock that formed in the deep equivalent of a “fault” in the Blue Ridge basement complex. We call it a “shear zone” most of the time, but a better descriptor would be “high strain zone.” These rocks are STRAINED, sheared out from original crystals with shapes akin to dice, transformed into platy flakey smears as thin as crêpe paper. The protolith rocks here are Mesoproterozoic in age, granitoids related to the Grenville Orogeny and the formation of Rodinia, but the shearing is younger, related to Appalachian mountain-building (making Pangaea) during the Paleozoic.
Surrounded by dirt and deciduous leaves, this is a palimpsest view into the Wilson Cycle.
There were not a ton of outcrops on this hike. A few isolated boulders perhaps, but mostly it was trees and trees, and trees. Catching a glimpse of such epic rocks almost completely obscured beneath dirt and leaves was a beautiful moment for me, akin to shafts of sunlight piercing the space between leaden clouds on a dismal day. You can imagine the heavenly choir of angelic voices singing in my mind…
If you will forgive me a moment of sentimental analogizing, I’m reminded of the national moment at hand. Today is the transition out of an era of hatred, fear, nonsense, and death, into an era that will hopefully be guided by empiricism, empathy, and an economics of equality.
This past year has been hellish: not only has a deadly pandemic been nurtured through neglect by the nation’s elected leaders, but the soon-to-be-ex-president has given a full-throated endorsement of racism and racists, and trained his followers in the fine art of ignoring facts. (Rereading Orwell’s 1984 four years ago turned out to be quite a good call.) On top of those national ills, my family and I moved to a new town and new jobs and new everything, pretty much at the precise moment when it was near-impossible to make new friends and nurture new relationships with colleagues, students, neighbors, and such. Though we get outside plenty, the social isolation feels a lot like cabin fever.
It’s been really hard for me to focus on work this year, on creativity, on much of anything scholarly, as the world around me burns and is debased and injects my dreams with anxiety.
I write now, in early 2021, after a year of near stasis on this blog, optimistic that things are getting better, and that I’ll soon be able to write more. I regret my lack of productivity here over the past year, but there have been more vital things that needed my attention, from moving four tons of rocks to my new lab to repairing my new house to facilitating emergency room visits for my son. Thankfully, being infected with COVID-19 hasn’t been one of them. But I have to tell you: the past year has been HARD. It’s been really hard. I’m not sad to shut the door on the Trumpocene. It’s been a tumultuous year without much joy.
But there’s something about deformed rocks that gets my pulse beating. The hike may have been mostly dirt and gray vegetation, but here was a glimpse of something beautiful, something meaningful, only just revealed. The past year may have been bleak, but I have high hopes that tomorrow is wonderful, and beautiful, and leads to the satisfaction of understanding, of perspective on the big picture.
Here’s to more ultramylonite in the coming years, and less dirt.
18 January 2021
First Light: Switching on Stars at the Dawn of Time, by Emma Chapman
Emma Chapman is keen on understanding the first stars. The first stars are different from modern stars, in their composition as well as their size. Specifically, Chapman notes that the earliest stars (unchronologically named Population III in contrast to modern Population I) were huge (20 solar masses) and “burned” (fused) hydrogen for 10 million years, followed by helium for 1 million , and then beryllium → carbon (300 years), oxygen (200 days), and silicon (2 days), for proportionately less and less time in the years remaining to them. Their life cycles went by quickly. Chapman is apparently typical of astronomers in taking anything of higher atomic weight than helium as a “metal,” presenting the astronomer’s periodic table as one of the earliest figures in the book: hydrogen/helium/METALS METALS METALS. What distinguishes the first stars (Population III) from the rest is they had none of these “metals” at their start, just hydrogen. So the search for Population III is really the search for “low metallicity” stars. An extended analogy is offered in one chapter between cyanobacteria polluting their surroundings with oxygen, and Population III stars polluting the interstellar medium with metals. Just as stromatolites changed the ambient geochemical conditions on Earth forever, so too did Population III stars forever alter the cosmic trajectory by contaminating it with metals of their own generation. Archaeology gets invoked as an analogy too – how can an Egyptologist figure out what’s pristine about a newly discovered tomb, what’s been extracted by grave robbers, and what’s been introduced as more recent contributions? A similar task faces astronomers as they consider the various aspects of electromagnetic radiation they gather from the cosmos. The final chapter looks ahead to future missions / experiments, describing their intended design and what data they seek. All told, I found this to be an excellent book: it’s more detailed than something general, the sort of thing Neil Degrasse Tyson might write. Chapman writes about the search that motivates her whole career, and she writes with a zippy, cheeky passion that’s infectious.
Soonish, by Kelly and Zach Weinersmith
I’m delighted that in moving to Albemarle County, I’ve got the Weinersmiths as neighbors. Their daughter is not too much younger than my son, and both families have taken a similar approach to the COVID-19 pandemic, leading us into isolation, but that’s bad for the kids, so we get together weekly for well-ventilated hikes at the land around one or another’s house. Zach writes the popular webcomic Saturday Morning Breakfast Cereal, and Kelly is a parasitologist. They both describe themselves as nerds. This book, their first joint collaboration, is an exploration of ten emerging technologies. They look at cheap space travel, mining asteroids, programmable matter, augmented reality, synthetic biology, and personalized medicine. The value of this book is that the two authors are extremely fastidious about tracking down true source material, and striving very much to not be wrong. But that scholarly dedication doesn’t imply a staid or stuffy book. Far from it, the text is laden with goofy jokes and evocative analogies, and every few pages is one of Zach’s cartoons. The humor is like the compressed air beneath a hovercraft – it lofts the whole narrative up, and carries it along through a tremendous review of the relevant literature. The Weinersmiths have made great use of footnotes, too – each contains a pithy clarification, an odd tangent, or an amusing joke. Super enjoyable, and super informative.
Consider Phlebas, by Iain M. Banks
Many moons ago in the middle of the pandemic, I asked for recommendations about books to read, and this science fiction novel was recommended on the basis of the fact that one of its scenes took place “in a batholith.” That’s all I knew about it going in, but I was able to get a paperback copy for a few bucks, so why not? It turns out this is the first novel in a series of books, all set in the future of what appears to be our galaxy. This one details a minor plot point in a larger war between two societies. The arc of the story follows the efforts of an agent on one side of this conflict in his attempts to locate and capture a self-contained artificial intelligence capsule developed by the other side. (It is this AI, called a “Mind,” that has hidden itself in a tunnel system that was bored into the cited batholith.) It turns out to be quite a series of adventures for the agent to get to the Mind and extract it. It’s a high adrenaline book with a lot of violent and spectacular occurrences, and pluck and luck on the part of the protagonist. Many of Banks’ details are familiar (trains, for instance), but others are imaginative and original (the idea of ring-shaped planet-equivalents called orbitals). It manages to feel distinctly alien while also resonating as relevant to a human at the same time. I wasn’t thrilled with the ending, but the reading of the novel was enjoyable and escapist.
The Young Earth: An introduction to Archaean geology, by E.G. Nesbit
This is an accounting of Archean geology by one of its practitioners. It covers igneous, sedimentary, and metamorphic processes relating to the Archean, with particular attention given to TTG suites, komatiites, stromatolites, distinctive characteristics of Archean sediments, iron formations, and the fossils of ancient microbial life. It was surprisingly readable for an academic work. It felt a bit dated (it was published in 1987), but it felt authentic and informed too. I am glad to have read it – it definitely expanded my horizons beyond the Canadian and South African outcrops I know to emphasize Australia, Greenland, and Mozambique — but I would be even more glad for a 2021 2nd edition!!