30 July 2022
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!
1 July 2022
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.
Field of view is about 1 meter. Sorry to have neglected a sense of scale; mea culpa.
24 June 2022
Earlier this week I showed an outcrop of overturned finely-bedded Lynchburg Group meta-sediments (Neoproterozoic in depositional age). Today, we revisit that same site, but this outcrop is 30 m away, and directly adjacent to a major soapstone body:
You can see the foliation is much more extreme here, with bedding obliterated, and that foliation has been kink-folded. Annotations:
These are probably Alleghanian-aged structures (both the foliation and the kinks that deform the foliation).
Here is a second example, located about 1 m away from the one I just showed:
Folds have been few and far between for me lately; so this was a nice treat. Happy Friday!
21 June 2022
One of my favorite tricks is using bedding / cleavage intersections to identify tectonically inverted strata.
On a field trip yesterday to check out soapstone quarries in the Albemarle/Nelson border region, I got to see this lovely example of Lynchburg Group metasediments that showcased a textbook example of the phenomenon:
Bedding was initially horizontal, or close to it, and cleavage (formed under tectonic compression) initially vertical. Subsequent deformation rotated the beds here, first dipping shallowly to the left, then steeply to the left, then vertical, and now steeply to the right. Meanwhile, the cleavage tipped over to the left, and the angle between cleavage went from a right angle to increasingly acute. Now, both bedding and cleavage dip to the right, but bedding is steeper, and cleavage is more shallow. That relationship is a handy shortcut for spotting overturned beds.
I’m grateful to Chuck Bailey from William & Mary for bringing me along on this trip.
29 May 2022
My wife just got back from a backpacking trip along the Lost Coast of California, from Mattole to Shelter Cove.
This is along the northern stretch of the San Andreas Fault, just south of the tectonic triple junction at Cape Mendocino.
My wife was kind enough to document some of the geology along the coast there, and to allow me to share the images here…
The local rocks are siliciclastic turbidites, shales and graywackes mainly – with a bit of conglomerate thrown in. These were deposited in deep water due to density currents (underwater avalanches called turbidity currents), which drop their load of grains in order of the particles’ weight, as this boulder of stacked graded beds shows:
A couple of close-ups of laminations and cross-bedding within the sandier turbidites, again showing a fining-upward pattern:
Here’s a muddier package, interspersed with sandy layers:
These deep sea sediments were scraped off the subducted Farallon Plate during the Mesozoic, and were crumpled and deformed as they joined the accretionary wedge. The contrast of the light sands and dark muds shows off the resulting deformation well:
Is it a fold or a fault?
This is my favorite of the photos my wife brought back: Our friend Kristie stands in front of a shale-dominated outcrop, but the handful of graywacke layers show a neat pop-up feature (to her left):
Let’s zoom in:
Annotated, with faults in yellow and kinematic indicator arrows in red:
This outcrop shows a scaly pattern, with a vertical foliation, suggesting it was a more dispersed zone of deformation, a shear zone within the subducted sediments.
Like much of coastal northern California, the Lost Coast has experienced uplift. Once the downward drag of subduction was relaxed, it allowed the flexible edge of California to bob upward. As evidence of that, consider this angular unconformity:
The lower half of that outcrop is tilted, folded, and faulted turbidites like those we have been looking at, but then there is a prominent line of light-colored boulders marking an ancient erosional surface, probably a wave-cut platform. Above that, plenty of beach gravels to a thickness of many meters, much like the modern beach in the foreground. All that was at or below sea level, and now has been lofted well above the reach of the waves.
This recent uplift is preserved in the shape of the land, too, like the two prominent marine terraces seen in this oblique shot along the coast:
Inspiring geology can be found along the Lost Coast.
16 May 2022
On April 25th, it was announced that Elon Musk had arranged to buy the social media company Twitter. He had just attained majority shareholder status a few weeks earlier. I’ve been an avid Twitter user for twelve years, accruing 11.5K followers over that interval, and very much enjoying the conversation — but I decided to leave the service when the sale was announced. Musk has articulated both an interest in less moderation on the forum, and a few days later shared a cartoon of what is presumably his political perspective, which is that the right is unchanging, but the left is more extreme. These harbingers potentially clear the way for rightwing extremists to repopulate Twitter. Chief among them may be the former president and coup cheerleader, and Musk has more recently stated that he would reverse TFG’s permanent ban on Twitter. I want no part of a space that lets hatred flow, poisoning the public discourse. So I decided to leave.
But it’s more than that: The increased time I’ve spent on Twitter over the past several years has led to some negative consequences. For one, it’s meant more of my geocreative energy has been expended in that space, with a consequent neglect forming here on my blog. I’m not sure about the role of blogs in the modern Internet landscape, but long form is probably a medium better suited to my talents. Second, there’s the issue of how Twitter impacted me emotionally: I feel like the constant stream of horrible news – about TFG, about COVID, shootings and racial injustice, the continuing lack of progress combating climate change, about the Supreme Court, about half of my fellow Americans — it’s all such a bummer. Stress and depression result. My wife first identified this trend: the more time I spent on Twitter, the grouchier I became. Finally, it’s just about time and attention. I had fallen into the habit of constantly checking Twitter – on my laptop, on my phone – a sort of addiction to the site. It didn’t feel healthy, and it distracted me from focusing on other matters, on whatever I was doing in that moment.
So I left; I deleted the app from my phone; I deleted the Twitter widget from this blog.
The past couple of days have brought another development, with Musk proclaiming the acquisition deal was on hold, which raises the possibility that I could ethically see my way to returning, but the issues outlined in paragraph 2 would still persist, so if that came to pass, It would be most healthy if I were to change things up a bit.
We’ll see. For the time being, my plans are to put my geocreative energy into a new video series (I’ll post about it here once it’s up and running) and into finishing a few case studies for my online Historical Geology text”book.”
13 May 2022
A terrific debut book by Robin George Andrews, who trained as a volcanologist but diverted from primary research into popular science writing. (He has also done a bunch of freelancing for National Geographic, Scientific American, and the like.) The book profiles Kilauea, Yellowstone, Ol Doinyo Lengai, the oceanic ridge system (including Iceland), the Moon, Mars, Venus, and the cryovolcanoes of the outer solar system, plus bookending diversions into Vesuvius and Fuji. I was surprised at how much of the page count was devoted to extraterrestrial volcanism, but that decision certainly leaves plenty of Earthly volcanoes available to be profiled in Super Volcanoes II. The writing style is very excited and skews to the popular side of the jargon-fluff spectrum. The decision to de-emphasize jargon is laudable, but I found that the language can tend to be a bit flowery, especially in the first half of the book. For instance, he refers to the magma chamber below Yellowstone as a “dragon,” a “cupola,”, a “missile,” a “grenade,” and (you can hear the thesaurus pages flipping) a “wyvern.” It erupts “shattered fire.” These metaphors can be doubtless engaging with some audiences, but my taste is for a bit more direct language. It’s a fine line, and I’m not sure whether there’s a clear way to nail “just the right amount of technical detail,” but I think one technique (employed by Andrews) is to weave in brief interviews with working volcanologists, allowing them to use their own words to describe eruptive phenomena, which then gives Andrews the latitude to “translate.” He does a fine job with presenting these people as humans, and somehow makes the reader feel welcomed by the volcanological community. All told, I found Super Volcanoes an enjoyable read, and it will have a place of honor on my geological bookshelf.
6 May 2022
Underfoot: A Geologic Guide to the Appalachian Trail, by V. Collins Chew
Published in 1988 by the Appalachian Trail Conference, this volume is a very AT-focused look at east coast geology. It’s also out of date, and a little hand-wringing when it comes to making clear conclusive statements about the arc of geologic history. The summary of geologic events is written for the beginner, not the professional. There’s lots of talk of forces and cracks and fire and ice, but you won’t hear “chlorite,” “greenschist,” or “mylonite” anywhere herein. And it’s not just eliding jargon; there’s revisionism, too. For instance, “Neoproterozoic” has been rebranded as “Z Time” to make things simpler for the novice. Most of the book is a geography based explication of the rocks found along the trail (as if hiking from Georgia to Maine) and a brief synopsis of their formation stories. The book is in black and white, and attempts to show geographic maps, geologic maps, and paleogeographic maps in a common template, which is a noble goal that is unmet. It would be a good thing to publish a second edition of the book in color, with updated science and a graphical design team.
Mapping Mars, by Oliver Morton
Morton’s first book, and the last one for me to read. I wish I had read it when it came out, for it is a bit dated at this point, a point that I’m sure delights Morton as much as it delights me – We have learned so much more about Mars since 2001; we have explored so much more. The map is more detailed, the processes better constrained. Still, this is a very readable account of about a century of scientific thinking on the red planet. We’re lucky that the past two decades have been so productive in our explorations of Mars, but this shows how we got to where we are. Morton’s style in writing is an absolute delight to read, and he employs a very similar format here as with his other books, The Planet Remade and Eating the Sun: he interacts with key workers in the field, attending their conferences and sharing conversations with them. In Mapping Mars, he also explores imagination’s role in our understanding of Mars, both in terms of driving scientific thinking but also in terms of its influence on fiction. In particular, Morton gives a lot of attention to the work of novelist Kim Stanley Robinson, who made Mars his beat for many years.
How to Make an Apple Pie from Scratch: In Search of the Recipe for Our Universe, by Harry Cliff
An exceptional read about the most basic and most elusive of topics: what is the universe made of? Taking inspiration from Carl Sagan’s Cosmos quip about “If you want to make an apple pie from scratch, you must first invent the universe,” Cliff (a particle physicist) provides a unique and insightful narration for what we now understand matter to be made of, and how we got to understand it. He is a very funny explainer of science, and what I really valued about this book is how well it blends theory and experimental results – I was able (for the first time) to follow the logic of inquiry all the way to the point where it is revealed that particles as such don’t exist, and are instead just vibrations within quantum fields. There’s just the right amount of repetition of key points, and Cliff provides a superb example of the technique of explaining a concept before naming it. Never before have I understood with a gluon does, or why the Higgs boson was such a big deal. All in all, a top-notch piece of popular science writing. Highly recommended.
A Gentleman in Moscow, by Amor Towles
I wouldn’t ordinarily gravitate toward a novel about a Russian count in the aftermath of the Bolshevik revolution, but everyone raved about this book, so during the dark days of the pandemic last winter, I read it… and I loved it. This is what a novel should be – a masterfully told story where you are led into caring deeply about fictional characters. The basic set-up is that the highly-cultured, highly-principled protagonist is imprisoned in a hotel for the rest of his life by the anti-nobility sentiments of the new government, and he makes the best of it, in style. The hotel is a source of luxury items (in particular, the count favors good wine and food) as well as exotic guests, several of whom prove pivotal to the Count’s fortunes. It’s also a source of antagonism, as petty apparatchiks act in ways to constrain the Count and imperil his happiness. But in a way, these plot points are really just foundational architecture for the main show, which is Towles’s tremendous abilities as a writer. I can’t wait to read his other novels.
The Galaxy, and the Ground Within, by Becky Chambers
The fourth (and apparently final) novel in the superb Wayfarers series examines issues of culture and community when people of four species are brought together by a crisis and have to isolate in place. I’m not sure if Chambers was influenced by the early COVID lockdown to write this tale of disparate personalities placed into close quarters by circumstance, but it’s a real delight that none of the five main characters are human beings. For those who aren’t familiar with the series, The Long Way to a Small, Angry Planet opens the series with a human protagonist and his alien (to us) spaceship crew. It was followed by A Closed and Common Orbit, which explored what it means to be a person (from the perspective of an AI that inhabits a robot body for the first time). Record of a Spaceborn Few, the third novel, looked at humanity’s future in space, with relatively few appearances by non-human species. To me, the sapient alien species Chambers dreamed up were one of the creative delights of the series, and so it pleased my palate plenty to return to exploring their unique circumstances in this final book. Stars, what a great series!
The Hate U Give, by Angie Thomas
A novel that feels all too real, considering the periodically-repeated American tragedy of a white police officer killing an unarmed Black person. The story of the incident is told by a teenage Black girl living in an urban black neighborhood but going to school in the dominantly-white suburbs. Her father is a former gang member and Black Panthers supporter who runs a small grocery store in the neighborhood. She has older and younger brothers, and a supportive mother who works as a nurse. Her friends at school are a mixed race group, and she draws particular support from her white boyfriend. Navigating all this would be complicated enough, but then things go crazy when she witnesses a policeman shoot her childhood best friend, and then the local gangs react, and the media reacts, and politicians react, and the reactions beget more reactions, and the whole situation gets wound up very tightly. Thomas’s writing is extremely effective at drawing the reader into the main characters point of view. She is also a master of dialogue, and I found myself savoring the different diction employed by the various characters, each speaking in a way that evokes their essential circumstances. Top notch, and worth all the praise it has received.
15 April 2022
A guest contribution for the Friday fold, from reader Christian Gronau:
Christian reports that this is located on the
North side of Hwy.11, 20 miles east of Saskatchewan River Crossing, Alberta. Eastern foothills of the Canadian Rocky Mountains.
Faulting and folding in Early Cretaceous Luscar Group sediments. Typical repeating sequence of sandstone, siltstone and coal.
Thanks for pitching in, Christian! Happy Friday to all!
21 March 2022
How the Word Is Passed: A Reckoning with the History of Slavery Across America, by Clint Smith
A really outstanding book. Clint Smith, a Black poet and academic, visits seven places that have important ties to the history of American slavery. Many of these places are focused on tourism and education, with a goal of spreading understanding about how slavery functioned in this country. One of them is on the mountain next to where I teach: Monticello, Thomas Jefferson’s home and plantation. Visiting it, Smith talks to other visitors and to the tour guides who lead them through the place, lead them in thinking about race, power dynamics, economics, and the personalities involved. Smith’s writing is superb, and I have rarely read anything so evocative and essential. This would be my top reading recommendation to any American. Slavery is America’s original sin, and the racism is has baked into our society still harms today. But while Smith could have stopped there, he goes deeper into a question that not enough people consider: what is the right way to teach about slavery in America? How do public-facing institutions like Monticello grapple with the presentation of ideas and perspectives to a public which is quite diverse in its interest and acceptance of the reality of American injustice. A fascinating and well-reported read.
A Grown-Up Guide to Planet Earth, by Christopher Jackson
I listen to about half my books as audiobooks, and I stream them via the service called Audible. Unlike those, this 6-episode work is an Audible original, unavailable elsewhere (including in print). In it, the articulate English professor of geology Chris Jackson describes various aspects of our planet, weaving in “on the scene” audio from various places and interviews with other geologists. It’s very approachable, and I found it held my attention despite my already being familiar with most of the concepts being discussed. One strength of the initiative is Chris’s informality, and how inseparable that is from his enthusiasm. He’s chosen a great group of geoscientists to interview as part of the effort, including old friends like Kayla Iacovino as well as new voices I hadn’t previously known of. Each episode is tidily packaged, and you could listen to it on your morning commute or while you’re cooking dinner, blending in-studio narration with dialogue and on-the-scenes reporting. Lots of fun, and recommended for the geological newbies in your life.
Horizon, by Barry Lopez
Barry Lopez produced so many wonderful books over his career as one of America’s preeminent nature writers. He died late in the first year of the pandemic (of cancer rather than COVID). There are few other writers like Lopez, and I’ve found inspiration in his pages for decades. This volume was no exception – it’s a very strong collection of essays exploring wild places and humanity’s relationship to them, and to each other. Some feel very familiar – some are even places from which Lopez has previously reported, and in Horizon, he circles back and reexamines them from the perspective of being close to the end of his own time on Earth. Others are new and distinctive and in some cases totally shocking. One of Lopez’s great strengths is his interest in exploration, but one criticism I would offer of his writing is that he often dwells too long (for my taste) on historical exploration, on the machinations of white men long dead. Here, too, I feel his indulgences in the vagaries of James Cook’s life and work present a big stale biscuit wedged amid much richer fare derived from Lopez’s own lived experiences. But the strength of those personal essays are profound, and they resonate deeply with me. I’m sad this will be the last new work from Barry Lopez. May he rest in peace as his works endure and reach new audiences through the magic of reading.
Yellow Bird, by Sierra Crane Murdoch
An interesting book, with two narrative centers. One is the fate of a man who disappeared (and was presumed murdered) while working in the oil shale boom in the Dakotas (the fracking frenzy that tapped the Bakken Formation). The second is the woman who obsessively sets out to solve the case, through tenacity and guile. Her name is Lissa Yellow Bird, a native of the Fort Berthold Indian Reservation, who has a checkered history, a fierce determination, and an instinct toward nurturing those she loves. Yellow Bird ultimately develops a tight friendship with the book’s author, reporter Sierra Crane Murdoch, which makes the book feel more personal and intriguing than it would have if Murdoch kept her own presence out of the narration. What results is a very intimate look at the lingering manifestations of U.S. colonialism on Native peoples, warped by boomtown economics and infused with the stink of petrochemicals. Greed and violence have been the essence with which U.S. policy has treated its indigenous peoples, and this book manages to explore that idea both in the grand sweep of history and the microcosm of this one particular woman, solving a murder in her own idiosyncratic way. A dramatic story, evocatively told.
The Story of the Earth in 25 Rocks: Tales of Important Geological Puzzles and the People Who Solved Them, by Donald R. Prothero
A very clever idea for a book – 25 neat and tidy chapters exploring Earth history and process by looking at specific rock types. Prothero is an old hand at writing, and has churned out a workmanlike book as a result. It could have stood another round of editing, I think, but is still a serviceable volume documenting the importance of rocks like komatiites, lunar anorthosite, blueschist, turbidites, or the outcrop at Siccar Point. I could see assigning some of these chapters (~10 pages or so) to students in Historical Geology as prompts to their thinking about how to solve geological enigmas through collaboration, logic, and multiple datasets. As a professional geologist, I am not sure that any of the rocks detailed in the book were surprises for me, but Prothero has a great strength in really caring about the arc of scientific thinking, and who wrote what, when. So I definitely gained a fuller appreciation of the backstory behind the interpretation of some rocks as a result of “reading*” it. (I actually listened to it on Audible, and I must say that this was one of the worst audiobook renditions I’ve heard, as the narrator consistently mispronounced almost every bit of geoscientific jargon – very grating on the eardrums. Read it on paper instead, would be my advice.)
The Ministry for the Future, by Kim Stanley Robinson
A novel about humanity’s future living as a society on a warming planet. The first chapter is among the most harrowing things I’ve read, in fiction or in reality. I won’t reveal any spoilers here for that entry point, but I will encourage you to read it. The short version is that climate change is bad, and people get hurt. From there, different characters take on tasks of healing the world, grappling with the complexity of climate, glacier dynamics, transnational politics, economic incentives, and messiness of interpersonal relationships. I will now spoil the novel’s main point, which is that (at least in this fictional universe), humanity solves climate change and nurtures into existence a world order that is sustainable. Along the way, various insights are achieved and various machinations developed, some of them clearly ethical, others dramatically less so. To read something hopeful about climate change is a nice change of pace, and I found myself engaged throughout the novel, with the possible exception on a deep dive into the economics of a particular approach to decarbonization.
The Calculating Stars, by Mary Robinette Kowal
A novel, the first in a series, that tracks the development of the U.S. space program in an alternate reality wherein a massive meteor strikes the Mid-Atlantic in the aftermath of World War II, wiping out D.C. and triggering unstoppable global warming. The U.S. government relocates to Kansas and kick-starts an aggressive Moon/Mars colonization effort in the 1950s, racing against time to save humanity by getting off the planet. The novel is narrated by a “computer” (in the Hidden Figures sense of the word) and former pilot, Elma York. Elma is married to an engineer, and after an exciting and harrowing first chapter wherein they survive the meteorite strike, the Drs. York move to Kansas and become integral to the space program. Elma ends up leading a diverse group of women pilots and computers to initiate a female astronaut program. It’s sort of interesting to be immersed in 1950s sexism and racism amid the struggles of the space race. Attention is also given to shaming characters for their mental health and use of corrective medication. Real-life figures like Werner von Braun and Mr. Wizard are woven into the narrative that is principally made up of fictional characters. An additional dash of distinctive flavor comes from the Yorks being Jewish, and a fair amount of attention being devoted to their practice. My chief complaint is that the wink-wink, nudge-nudge sex scenes between the Yorks are described in language I can only describe as cringe-inducing. There are many of them, and author Kowal seems to pride herself in masterful innuendo that in fact comes off as pretty childish. My second complaint is that there are really no big plot twists after the discovering of the climate-altering effects of the impact. The narrative just goes forward, documenting the journey of this fictional first woman into space.
Origin: A Genetic History of the Americas, by Jennifer Raff
An important contribution to understanding the peopling of the Americas, blending archaeology and genetic sequencing. This important new line of data is critical for evaluating the various hypotheses of when and from where Native Americans arrived on these continents. The author, Jennifer Raff, currently the President of the American Association of Anthropological Genetics, describes her own work in an “ancient DNA lab,” extracting, amplifying, and evaluating genetic information from human remains recovered from archaeological sites, but also recounts DNA results from living Native Americans. This she attempts to tie together with the vast suite of archaeological insights, with all their attendant details of place, dating techniques, and associated technologies. The result is a complicated tangle of genetic markers, site names, tribal affiliations, and competing hypotheses. I think the book would be most valuable for a reader who has already mastered the nuances of American archaeology, but for me (being new to the details of places like Meadowcroft, tools like Clovis points, and ideas like the Kelp Highway, it was a lot to keep track of, especially once the alphanumerical naming jargon of various genetic markers started being introduced. Still, to have it all in one volume seems to me to be a very valuable manifestation, and I’m grateful Dr. Raff has orchestrated all this information into a single book. The other major thing I think she deserves recognition for is an unceasing and unrelenting emphasis on ethics in anthropology. The book repeatedly details colonial and racist attitudes and actions of anthropologists both past and present, and demonstrates a better way forward, integrating scholarly research with the modern needs and interests of living Native Americans. Conversation and consent must take place prior to any investigation. Raff puts her respect for the indigenous perspective front and center, and doesn’t let the reader forget that the insights she shares were developed through cooperation with the descendants of the people she studies.
Rosewater, by Tade Thompson
A science fiction novel, the first in a series. The basic set-up is that an alien organism has installed itself in a big way in Nigeria, sharing both healing powers and mind-reading ability with the humans with whom it comes into contact. A town grows up surrounding this great dome-like extraterrestrial presence; the doughnut-shaped titular Rosewater. Living in Rosewater is the protagonist of the novel: Kaaro. He is a “sensitive,” one of the mind-reading types. The novel is structured around his evolution across two timelines: “then” and “now,” so you as the reader both get his backstory and the urgent current crisis as he navigates trauma, government bureaucracy, romance, treachery, and just plain weirdness. These “then” and “now” chapters alternate, and so sometimes its confusing (at least to me) which moment I’m immersed in, but ultimately the past informs the present in well-apportioned chunks of narrative arc. It’s very well-written and full of evocative detail. I’ll be reading the sequel next.