16 September 2022

Friday fold: isoclinal limestone near Harrisonburg

This weekend, my family and I traveled to a little agrotainment complex north of Harrisonburg, Virginia, a joint called Back Home On The Farm. It featured a corn maze, hayrides, petting zoo, apple cider donuts, and pumpkin picking. All typical fall frolic; good clean fun.

But there were also big blocks of limestone everywhere on the property. I did my best to check them all out. I was mainly scanning for stromatolites, which occur with some regularity in the Conococheague Formation. This site was mapped as New Market + Lincolnshire + Edinburg Formations, but these blocks look most like the Conococheague to me.

No stromatolites, but I did find some nice tight folding in one block:

This is pretty intense deformation of originally planar beds, and I’m tempted to think it might be soft sediment deformation based on the massive overlying bed (which is undeformed). But it could also be a weak zone that crumpled during Alleghanian mountain building. Your thoughts?

Happy Friday to you!

Comments/Trackbacks (3) >>

5 September 2022

Book report

Great Expectations, by Charles Dickens

I’ve recently enjoyed David Copperfield and A Tale of Two Cities, so I re-read Great Expectations. Somehow we ended up with three copies of it in our house. It is what it is, a solid novel by a talented writer. The great strength of Dickens, I’ve come to appreciate, is his wacky characters – the level of detail in his portraits of these imagined humans is profound, often endearing or revolting, and frequently amusing. Great Expectations had terrific characters in spades – notably Jaggers and Wemmick and Miss Havisham. But the overall arc of the story was far less satisfying than I had grown accustomed to, with Dickens’ other great works so recent in my memory. The fact that Pip never really reaches reconciliation with Estella, Joe, or Biddy seems a real shame, and I found myself feeling both sad for him and also a bit disappointed in him, a sour taste in my mouth as I shut the back cover of the book. Magwich’s end also felt abrupt and unpoetic, with Pip slipping him knowledge about Estella in the old convict’s final moments, and … for what? It felt pointless and distracting to me. And Estella herself – she never grows out of her awful attitude, even when she gains awareness of it. She’s just as mean to Pip in the end as she was in the beginning. Ultimately, I didn’t love this book.

Termination Shock, by Neil Stephenson

A novel of humanity reckoning with climate change, rather similar in many regards to Kim Stanley Robinson’s The Ministry for the Future. Both novels feature a middle-aged European woman as protagonist: a bureaucrat for Robinson, and the queen of the Netherlands for Stephenson. Termination Shock distinguishes itself with significantly more action than Ministry, though: there’s more fighting and interpersonal interrelating. The plot is basically this: a wealthy Texan convenes a group of wealthy people who live in low-lying areas of the world to participate in a private geoengineering enterprise, launching sulfur into the stratosphere (reducing the solar energy flux and thus cooling the planet). These people are directly threatened by rising sea level, and they have the means to take action to stop that sea level rise. They do so. Then what? Well, some countries are gratified; others are incensed. The action triggers a counteraction, and the plot drives forward. Stephenson’s great ability is to weave in many strands from life into his novels. This one cites COVID-19, COVID-23, and COVID-25 as recent pandemics that humanity has struggled through; and delves deep into Sikh culture, the feral hog problem in the American South, and China and India’s battle over their border in the Himalaya. He also manages to invoke all kinds of recently-developed technology: Directed-energy weapons (like those that are thought to cause Havana Syndrome), an EMP, and deepfake videos all make appearances, many serving as key turning points in the plot. Drones are EVERYWHERE in this book, thoroughly saturating the near-future imagined by Stephenson. Overall, I felt like this was a solid novel, and I enjoyed reading it. Though fiction, it thoroughly explores the geopolitical ramifications of someone deciding to geoengineer the climate. It wasn’t as impressive as Seveneves, but not as anticlimactic as Cryptonomicon.

A Short History of Nearly Everything, by Bill Bryson

Another re-reading. In popular science, it seems to me that there are relatively few ways that authors choose to tell the story of the universe from beginning until now. What strikes me as worthwhile about Bryson’s attempt is that he did it his way. It’s not a straight-up chronology of events from 13.7 Ga on page one until you and me show up on the last page. And it’s not a “history of science” either – it’s somewhere in between, with the order of topics discussed basically just Bryson’s preferred shuffling of the deck. But what you read in Chapter 12 doesn’t necessarily presage what will be covered in Chapter 13. That keeps it fresh, I think. I hope it goes without saying that Bryson’s wit is as charming here as in any of his other books – he has a very endearing way of writing, grounded in midwestern sensibility but seasoned with British style and snap. I first read A Short History of Nearly Everything shortly after it came out, but I know more now than I did then. And so I found my reading interrupted by stumbling over errors of fact or emphasis – for instance him saying that Hawaii is on a plate boundary, when the coolest thing about that archipelago is the fact that it’s so far from a plate boundary! It’s a pretty chewy tome, but I think worth reading if you haven’t already just for Bryson’s fresh “outsider’s” take on cosmology, Earth science, and everything in between.

The Egg, and other stories, by Andy Weir

I’ve really enjoyed two of Weir’s novels, and to my knowledge this is his first and only collection of short fiction. I listened to it on audiobook. The scientific acumen and technical practicality of Weir’s characters in The Martian and Hail Mary Project are absent in these short stories. These aren’t mini-Martians; they are their own distinct genre for Weir. He treats them differently. They feel like episodes of the Twilight Zone – most building up in a weird and unsettling way toward a “punchline” revelation at the end, recasting all you’ve just read and making you re-examine it with some level of “Aha, now I get it.” That’s the one great strength of this collection, and because it’s a relatively modest total number of stories, I think it would be regretful if I revealed any of the twists here… including one about the Twilight Zone itself…

Dreams From My Father, by Barack Obama

Obama’s first book, written after law school but before being elected to political office: a compelling, readable account of his boyhood and early manhood. It’s anchored with the effort of coming to understand his biological father, who looms large in his life despite the two spending only a week together in Obama’s memory. Obama, the first Black president of the United States, was deeply shaped by childhood experiences in Hawaii and Indonesia, time spent trying to organize people in Chicago for a more vibrant and durable community, and also a key visit, post-Chicago and pre-law-school, to his father’s homeland of Kenya. This singular figure in the American political world has a singular backstory, and this is the book where he lays it all out – circumstances and decisions good, bad, and ugly. The level of self-reflection is extremely refreshing to contemplate – considering his successor in the White House.

Comments/Trackbacks (0)>>

20 August 2022

Two erratics from coastal Maine

Happy Saturday! Here are two erratics (glacially transported boulders) that I saw last week in coastal Maine. This one shows prominent subparallel striations:

And this one, in the town of Penobscot, next to the greasy spoon called Bagaduce Lunch, shows aligned feldspars that suggest magmatic flow:

Nothing like a good erratic to get the weekend started off right!

Comments/Trackbacks (3) >>

19 August 2022

Second Nature, by Nathaniel Rich

This volume is a compilation of reporting that author Nathaniel Rich previously published (sometimes in rather different form) in a variety of periodicals, but mainly the New York Times Magazine. The general theme is humanity’s alteration of the natural world, for good or (usually) for ill. The first piece, on West Virginian lawyer Robert Bilott, was the basis of the recent Mark Ruffalo film Dark Waters. Other essays examine a mysterious disease killing Pacific starfish, toxic gas leaks in residential coastal California, artificial (lab cultured) meat, the rewilding of New Orleans in the aftermath of Hurricane Katrina, the tug-of-war of eco-sensitive development in Aspen, Colorado, efforts toward the de-extinction of the passenger pigeon, and more. A trio of pieces examines the impact of sea level rise along the Louisiana coast. Each was a well-reported, well-written read, and collections like this are valuable as tributes to the range of a writer’s interests. It’s mostly glum, partly uncanny, and not especially hopeful. These are interesting times in which to live, and Rich’s book documents some of the reasons why.

Comments/Trackbacks (0)>>

18 August 2022

Quarrying soapstone

Earlier this summer, I was lucky enough to visit a soapstone quarrying operation in Schuyler, Virginia, right on the Albemarle/Nelson County line.

These soapstone bodies are metamorphosed ultramafic intrusions into the Neoproterozoic sedimentary deposits of the Lynchburg Group. The protolith peridotite sill crystallized at ~580 Ma, meaning the host sediments are older than that (but younger than the Grenvillian basement complex that underlies both). Then both plutonic rock and sedimentary strata were metamorphosed during the Alleghanian Orogeny at ~300 Ma, thus becoming soapstone and metasedimentary rock.

We visited three separate quarries over the course of the day, but this was the only active one:

There’s a lot to see in that image: you can see the old quarry high wall (upper six berms) as well as a fresher face down at the bottom, where material has been removed more recently. The delicate vertical “fluting” you see on the old upper faces is from the previous extraction technology: drilling a lot of parallel vertical holes, and then breaking out slabs along that perforated weakness. Nowadays, they have a more efficient way of getting the rock out:

If that looks like a big chainsaw to you, congratulations: that’s pretty much exactly what it is, but the bar is more than fifteen feet long, and the individual carbide teeth are an inch square. They slice into the soapstone and polish it into slabs, aiming for bits that show veining so people will find it an attractive choice for countertops. Here’s a detail of one of the veins, made principally of talc (white) and pyrite (brassy).

But there was some structure to be seen, too. If you go back to that first photo and take another gander at it, you’ll note some diagonal fractures. Those are a source of some consternation to the quarry operators, since they are planes of weakness that can allow rockslides. Most challenging is when a steeply dipping fracture dips into a quarry wall, daylighting with a big wedge of rock above the fracture surface.

If you look at the fracture surfaces themselves, they show slickensides, so these are actually small faults.

They indicate an oblique sense of motion that presumably accompanied metamorphism. The soapstone is more foliated closer to its margins, where it is in contact with the Lynchburg Group metasediments. The most massive stone in the middle is most valuable economically. Between the foliation and the faults, there’s a lot of soapstone here that doesn’t make it to market – which means plenty for the curious visiting geologist to browse through and select samples from!

Comments/Trackbacks (3) >>

17 August 2022

Book report

Beneath the Rising, by Premee Mohamed

A novel of adventure, science fiction, and magic. Two teens from Canada embark on a mission to save the world. Though “mismatched” in terms of their demographics and wealth, they are united by the fact that they met as children when one terrorist’s bullet pierced them both. The story is told from the perspective of the boy, Nick, but what’s immediately crazy about the situation is his friend Joanna (nicknamed Johnny) is the smartest person in the world, having invented dozens of inventions that have reached every corner of the world and improved humanity’s lot. In the beginning of the story, she “does it again,” with a small, simple reactor that generates unlimited clean energy. But the new machine comes with a fearsome cost, bringing evil creatures into our world. Johnny knows how to stop it, but can she complete her globetrotting quest without Nick, despite his quotidian abilities? There pop-culture-infused banter is entertaining, but is there more to their relationship than meets the eye?

Mythos, by Stephen Fry

A free audiobook in Audible, at least through the end of this month. It’s all of Greek mythology, retold in the inimitable style of comedian Stephen Fry. It’s really, really good. Perfect bite-sized chapters, organized chronologically, and connecting the stories from antiquity with modern words and phrases. It is flooring to realize how much we are constantly surrounded by hand-me-downs from Greek mythology in modern American life, even if we are utterly aware of it. The antecedents in this collection persist in thousands of threads that bind together modern society. And it’s so well told! I found it absolutely charming to listen to; Fry’s language, voice, and choice of connections to elucidate make the listen a totally engaging experience. It’s scholarly, in a way – Fry backs out of the story to note areas of uncertainty when appropriate, about who begat who, or subtleties of translation, or where scholars don’t agree, but for the most part it’s a rollicking tale of good, evil, pride, greed, guile, innocence, and every other aspect of the human experience. Highly recommended.

How College Works, by Daniel F. Chambliss and Christopher G. Takacs

An interesting and readable report on a multi-year qualitative study of factors that manifest in a successful college experience. The study was conducted at Hamilton College in New York, which is selective, private, small, and well-funded. I found much of the study to be insightful and meaningful, for instance that the most powerful part of the college experience is connecting with other people – friends, effective professors, and mentors. Other parts, like the powerful sense of identity that comes from exclusivity, seemed to me to be antithetical to the realm of higher education in which I teach: the community college. Where I work, it’s all about open access: anyone and everyone in our community is welcome to attend. A comparison may be valid here. Elsewhere, the authors note the the “small class size” metric by which colleges are judged (by the U.S. News & World Report rankings, for instance) is a flawed measure: for every student in a sought-after small class, there are some number of students who couldn’t get into it, and are in some other class instead – a larger one, perhaps, or perhaps a small class they hate (a required freshman seminar can be more nuisance than nirvana if you can’t get into your top few choices). I see the psychological benefits of exclusivity similarly: those on the inside may well bond and meld due to the institution’s (or fraternity’s, or band’s) strict requirements to enter (including financial), but that means you don’t get to hear the perspectives of those who are shut out of the group. Community colleges don’t have that issue. But I digress: Overall, I found How College Works to be an inspiring read. Connecting with students to support their success is my primary goal, and the primary unit by which colleges should be evaluated should be students, not courses, departments, or other institutional metrics. It’s about the students. We do well to ask them what they think.

What If?: Serious Scientific Answers to Absurd Hypothetical Questions, by Randall Munroe

Such a fun book: I can’t believe it’s taken me this long to read it! (It was released in 2014; I listened to the Wil Wheaton narration.) The premise is that readers of XKCD send in questions – ridiculous questions – and then author Munroe does his best to answer them, with math, research, and humor. The result is very entertaining, and occasionally insightful. I had such fun reading it (listening to it). For what it’s worth, Wil Wheaton does an amazing job inflecting the nerdy umbrage of the text. Also worth noting is that the sequel, What if? 2, is about to be published, and based on a preview in this month’s WIRED magazine, looks to be just as delightful!

Comments/Trackbacks (0)>>

16 August 2022

Kinked metavolcanics of the Castine Formation, eastern Maine

Last week, I was in central-eastern coastal Maine, for a wedding, but I also made time for some geologizing. We stayed near Holbrook Island Sanctuary State Park, and spent several nice days there hiking and kayaking and exploring. The main rock unit I encountered is the Castine Formation, a Paleozoic-aged metavolcanic complex. The exact age appears uncertain: one source told me “Cambrian,” but elsewhere I see it listed as “Silurian-Devonian.” I used the fabulous app called Rock’d in the field as a guide for exploring.

I saw two principal varieties of rock: a coarse-grained lithology and a fine-grained one. Here’s a few views of the coarse stuff:

The coarse-grain size implies a certain violence to the deposition, and the grain shapes suggest proximity to the source. Note too the “matrix-supported” nature of the deposit: the largest clasts “float” in a finer-grained matrix, and don’t touch each other. This suggests very minimal winnowing of the fine material by consistent currents of water. Compositionally, these clasts are dominantly felsic, and were subjected to relatively low-grade metamorphism after they formed.

Here’s one outcrop I saw adjacent to Goose Pond, from a kayak:

(field of view about 10 m)

The cleanest part is under the overhanging tree branches in the upper left. Let’s zoom in:

(field of view about 3 m)

Those are some of the larger clasts I saw, with the biggest 0.3-0.4 m across.

So, in terms of interpretation: lahar deposits, or powerful pyroclastic flows?

This is part of Avalonia (or Avalon), a composite “microcontinental” terrane the originated adjacent to Gondwana, and accreted to ancestral North America during the Acadian Orogeny.

This one shows some well-developed foliation (running from lower left to upper right), induced by one or another episode of Appalachian mountain-building, I guess probably the Acadian:

The other major lithology, the finer-grained metavolcanics, appeared to be more susceptible to deformation. Here’s an example showing a large kink fold disrupting foliation:

(Apologies for using my bare feet for scale!)

Well-developed kink bands in tight proximity, folding foliation:

More distributed kink bands:

A conjugate pair of kink bands, one of only two such intersections I observed:

In two places, I saw basalt dikes cutting across the metavolcanic rocks:

These are probably Triassic in age, related to the opening of the Atlantic and the nearby Fundy rift basin. Note that they are neither discernibly metamorphosed, nor deformed.

In my experience, few things are as satisfying as exploring new and interesting outcrops, on foot and by kayak. For this, coastal Maine was a real treat: plenty of interesting texture and structure, exposed in a complicated 3D swath between the forest and the sea.

Comments/Trackbacks (0)>>

15 August 2022

Book report

Solitary, by Albert Woodfox

A first-person account of spending 40+ years in solitary confinement. Woodfox recounts his youth in New Orleans poverty, turning to robbery, being arrested, and then sentenced to Angola, the notorious plantation-turned-prison in Louisiana. He escapes at one point to end up in New York, where he learns of the Black Panthers, and transforms from a shiftless ne’er-do-well to a politically active change agent. Eventually he gets returned to Angola. There is framed for the murder of a prison guard, and his sentence jumps from a few years to life behind bars. Because of his political inclinations, he is committed to solitary confinement, in a cell by himself for 23 hours of every day. He can speak to other prisoners in adjacent cells, but for the most part he is utterly isolated. Somehow he manages to not go insane, and begins reading and educating himself. Time passes, lawsuits come and go, in many cases against Woodfox due to malfeasance on the part of prison officials, and his misery is compounded. The degrading manner he is treated with would make anyone cringe with indignation. After his third decade, his case becomes known to advocates in the wider world, who see his solitary confinement as a stark case of cruel and unusual punishment, and they push to change the practice. Woodfox also gets a retrial, and after the majority of his life incarcerated, he is finally able to walk out of Angola. Woodfox passed away the week before last, a free man.

Rules of Civility and The Lincoln Highway, both by Amor Towles

With these two novels, I’ve exhausted all the published novels by Towles, which is an absolute shame, because he’s such a good writer. Each of these books (with A Gentleman in Moscow being the third) is its own unique creation, a universe unto itself. The details really don’t matter too much to me, but the care in writing about them is astounding, and each has satisfying plot twists that were unforeseen (by me, anyhow) but help to create a neat narrative arc. Rules of Civility was such a great book in terms of the universality of its central theme, adorned with the most delicious details. Lincoln Highway wasn’t quite as strong of a story in terms of how much it spoke to me, but it did feature narration from the point of view of numerous disparate characters, some of them trustworthy, some of them simple, and some of them caught up in their own self-justified mischief. The facility with which Towles moves the story along, jumping between these multiple points of view, is impressive. All these novels are great, and such a wonderful joy to read. Top-notch recommendations to each!

The Internal Enemy, by Alan Taylor

A history of Virginia (and Maryland) during war with the British, particularly the War of 1812, its antecedents and aftermath. The specific focus here is how the slavery-based society of the pre-Civil-War United States left the slaveholding whites in constant fear of a violent uprising from those they enslaved. The title of this masterful history comes from the fact that they were battling on two fronts: the “external enemy” of the British navy, but also the “internal enemy” of their slaves. The author, Alan Taylor, is a UVA professor, and he weaves a well-paced exploration of how the British cannily exploited the fears slaveholders adjacent to the Chesapeake Bay while undercutting their economic success simply by accepting runaway slaves. Those who successfully escaped were given asylum aboard the British vessels. Most were eventually resettled in Bermuda or Nova Scotia, but to the Tidewater and Piedmont Virginian plantation owners, their great fear was that their former slaves would come back and wreak vengeance upon them. Recurring are characters you’ve heard of (Thomas Jefferson, for instance, James Madison and James Monroe), but also a family of Virginia landowners and slave-holders who squabble internally about choices that pit the moral instinct of some against the fraught relationship with their creditors, and their fears of their violence coming due in reciprocity.

For Want of Wings, by Jill Hunting

This nonfiction book is essentially a family history that attempts to draw together two partially connected aspects of the author’s ancestors. First, there is a deep commitment to the abolition of slavery in association with the notorious abolitionist (or “domestic terrorist,” depending on whose perspective you take) John Brown. Second is an interest in paleontology, and discoveries made in the American West under the guidance on Othniel Charles Marsh of Yale. The expedition west is chronicled in as much detail as possible: the author’s great grandfather is a student of Marsh’s, and she explores his biography as well as what he and the rest of the group saw out in the wilds of Kansas with assiduous research and some imagination. The most significant find is Hesperornis, a toothed bird from the Cretaceous chalk, which becomes known and celebrated as a transitional fossil, validating the idea of organic evolution. That’s much of the book, but not all – What remains is the author’s account of visiting Kansas herself, and chatting with the people she meets about fossils, and sharing a bit of her own life story, and that of her daughter, one of the founders of She attempts to draw these various strands together, heady with awareness of the contingencies that led to the present moment. There are a great many tangents in this book, which evoked for me the feeling I used to get (pre-e-mail) reading letters from friends. I think if I were the editor of such a book, I’d be tempted to trim those back a bit, but the effect of retaining them all is to create a sense of informal familiarity with the author.


Comments/Trackbacks (0)>>

30 July 2022

Well-preserved mudcracks in Belt argillite, Glacier National Park, Montana

I spent last week in western Montana, teaching my annual “Geology of Glacier National Park” for Montana State University’s Master’s of Science in Science Education program. As usual, it was a fulfilling and enriching experience.

There are many great things about Glacier’s geology, but a perennial favorite for me is the abundance of truly ancient primary sedimentary structures, like these mud cracks:

Originally formed during the Mesoproterozoic, these delicate patterns speak of a very shallow Belt Sea, where mud deposited at high tide or in the wet season was then exposed to the air during low tide, or the dry season, inducing desiccation and contraction. The example above shows the resulting mud cracks filled with more mud, but they can be filled with sand, too, as this inverted block shows:

In cross-section, the mud cracks make V-like shapes where younger layers “bite” down into their predecessors. Here’s an example in green (chlorite-rich argillite of the Appekunny Formation) and another in red (hematite-rich argillite of the Grinnell Formation):

My favorite new example of this phenomenon is one I’ve walked by a dozen times before without noticing. It’s on the trail up to Grinnell Glacier, at the spot just before the waterfall-on-the-trail, where the route was closed this year due to a hazardous snowfield crossing. Forced to have my lunch there instead of atop the stromatolites up top, I was forced to examine my new surroundings. I appreciated this one especially:

Here, though the mud was deposited under oxidizing conditions (=red), later reducing fluids moved through the sediment (or sedimentary rock), altering blotchy portions of it (=pale green). I love the “palimpsest” overlap between the oxidation/reduction contrast and the pattern of mud cracks. Whether you’re a geochemist or sedimentologist, there’s a lot to love in this slab!

Comments/Trackbacks (2) >>

1 July 2022

Friday fold: lithified python

A quick Friday fold that I observed last month in a boulder of riprap at Chippokes State Park in Surry, Virginia. I have absolutely no idea where this rock was quarried; but it doesn’t look like anything I’m familiar with in Virginia, so maybe the Baltimore Mafic Complex???

Anyhow, it’s not native to the Coastal Plain, but it shows a pleasing fold train of green and gray amid the black of the surrounding rock. I’m reminded of a python’s muscly meanders.

Folded epidote layer in a boulder of ripr

Field of view is about 1 meter. Sorry to have neglected a sense of scale; mea culpa.

Happy Friday!

Comments/Trackbacks (2) >>