22 March 2019
Here’s a deceptive Friday “faux”ld I saw last week on the South Page Valley Road whilst learning about the Martinsburg Formation outcrops there:
Looks like an isoclinal fold in this slab of siltstone, but the curvy lines are just concentric weathering rinds. Not a real fold at all!
I hope everything you see this weekend is more straightforward and less deceiving. Happy Friday!
20 March 2019
[Note: this book review was scheduled to run in the May 2019 issue of EARTH magazine, but with last week’s announcement that EARTH was being shuttered, I was notified that nothing contributors or freelancers had written scheduled for after April 2019 would be published, and the rights were returned to me. While that’s disappointing, it frees me up to publish it here instead. This review was improved with edits by Sara Pratt. Enjoy!]
In 2012, the mounted skeleton of a Tarbosaurus bataar was sold at auction in New York City for just over a million dollars. The Cretaceous dinosaur fossil originated in Mongolia’s Gobi Desert, and made its way to Manhattan via the U.K. and Florida. Some would say it was “smuggled.” Paige Williams wrote about the incident for the New Yorker magazine shortly after it occurred, and has now expanded that profile into a robust book that covers everything that led up to the incident and everything that occurred after.
“The Dinosaur Artist: Obsession, Betrayal, and the Quest for Earth’s Ultimate Trophy” is centered on Eric Prokopi, a Florida fossil dealer. Williams spends a substantial amount of time delving into his history, character and relationships with family and friends. She paints a nonjudgmental portrait, but she includes assessments of his business decisions from interviewees who describe him as reckless, if not unethical. Prokopi made a life for himself and his family structured around the intense joy he found in fossils: He discovered them, prepared them for display and sold them. Eventually, he went “big” with the enormous Tarbosaurus skeleton, which took more than a year to bring to sale, and which he hoped would net him more than a million dollars. Instead, it landed him in jail.
The essential tension in the book arises from the question of the value that commercial fossil hunters bring to paleontology. Whether you’re inclined to view Prokopi as a protagonist or an antihero is doubtless colored by where you come down on this question. Williams explores arguments for and against extracting and selling fossils, a discussion that acknowledges the merit that comes from discoveries or recoveries that wouldn’t otherwise happen, as well as the public outreach value that fossils can inspire when available for the public to access and own. For instance, “Sue the T. rex,” the most famous dinosaur at Chicago’s Field Museum, which receives 1.8 million visitors a year, is only there because of an auction. But there are significant downsides of private sales, such as the loss of taphonomic information about the fossil’s context in sedimentary rocks, and the fact that some fossil owners are not keen on sharing their new possessions. Astounding fossils, once sold, can disappear from public view, with scientific access lost forever.
And then there are the legal ramifications, which are complicated by notions of liberty and private versus public ownership, and the government’s ability to seize privately held materials, domestically or internationally. From the Boston Tea Party to the fall of communism, huge currents in social history lay the foundation for Prokopi and “his” Tarbosaurus skeleton. All of us are subject to these historical currents but Williams does a fine job showing their direct relevance to the way the saga of this particular dinosaur unfolds.
The book also includes lengthy tangential discussions on topics that are both foundational to the story, as well as near and dear to my own heart: Roy Chapman Andrews, Mary Anning and the post-communist political history of Mongolia. These historical discussions serve the greater narrative by laying the foundation for key characters in the larger story who collaborate or antagonize Prokopi. Each is well researched, and could stand alone as an essay worth reading.
Anning ran a fossil business out of Lyme Regis (“She sells seashells by the seashore”), in Dorset, England, not far from where Prokopi’s collaborator, the British fossil merchant Chris Moore, would set up his own shop. Andrews, often cited as the inspiration for “Indiana Jones,” was an explorer for the American Museum of Natural History, and the discoverer of the first dinosaur eggs, at Mongolia’s Flaming Cliffs. Without his swashbuckling escapades, we likely wouldn’t know as much about dinosaurs from this remote corner of the globe. The Mongolian history chapter is comprehensive and descriptions of travel and culture in the country are accurate. (I served as a U.S. Peace Corps volunteer in Mongolia in 1998–1999). The President of Mongolia at the time of the 2012 auction was Elbegdorj (most Mongolians only use a single name), a darling of American right-wing politicians and one of the principal forces in moving Mongolians into a free-market economy. Alerted by a lieutenant to the sale, Elbegdorj initiated a lawsuit that ultimately resulted in the skeleton being repatriated to Mongolia.
It’s wrenching to read about the stress that this imposes on Prokopi and his family as they move from their repossessed Florida mansion to Tidewater Virginia, and then Prokopi goes to jail, emerges again, and moves onto a tugboat. (His probation officer asks, “Why can’t you be normal?”) But it is also inspirational to read about the bloom of wonder that unfurls in Ulaanbaatar once the Tarbosaurus has its homecoming. In William’s narrative, the ancient bones take on a mythical character akin to Chinggis (“Ghenghis”) Khan, inspiring patriotism in the people of the Central Asian steppes.
We also get the fascinating backstory of Bolor Minjin, a Mongolian paleontologist, formerly of the American Museum of Natural History, and a National Geographic Explorer. She is the one who triggers the chain of events that ultimately stops the sale and results in Prokopi’s arrest.
“The Dinosaur Artist” screams out for comparison with Susan Orlean’s 1998 book “The Orchid Thief,” not only for the structure of their titles, or because both authors are staff writers for the New Yorker, but also because the principal characters are flawed, nonconformist Floridians who operate in a legal gray area collecting natural resources from public lands. I’ve read both books, and can say that while I really learned a lot from Williams, the writing in Orlean’s book is much more elegant and polished. That said, however, I think the events depicted in “The Dinosaur Artist” carry more weight in the grand scheme of things, and thus the book should be required reading for anyone interested in how fossils relate to the worlds of economics, trade, politics and the law.
18 March 2019
Last Tuesday, the weather was great, and I was on spring break, so I didn’t have to teach. There are a bunch of local outcrops I’ve been meaning to suss out, and it seemed like the time was right. I contacted my colleague Russ Kohrs, a teacher at the Massanutten Regional Governor’s School for Environmental Science and Technology (and an instructor at Lord Fairfax Community College), and we set out for Page County, Virginia, to a stretch of the South Page Valley Road between Massanutten Mountain and the South Fork of the Shenandoah River:
The Martinsburg Formation is a late Ordovician turbidite sequence, clastic sediments shed into deep water from a proto-Appalachian mountain belt. The source mountains were generated as an offshore volcanic island arc accreted to the ancestral North American continent (“Laurentia”) in an event dubbed the Taconian (or “Taconic”) Orogeny. The tectonic smash-up shoved rocks up into the air, making mountains, which erosion went to work tearing away at. The result was lots of mud and lots of sand, which was carried downhill (expending its potential energy) to be deposited on the seafloor.
The result was a lot of sand and mud, today turned into lots of shale and graywacke:
(Sense of scale: a heroic pose by Russ)
You’ll note these beds are not in their original ~horizontal orientation; they have been tilted and folded by subsequent mountain building; more on that in a moment…
For now, just appreciate that these rocks are made up of gazillions of tiny pieces of what used to be mountains – mountains that towered to the east over the Piedmont region, places like Washington, D.C., where one can examine their eroded roots today.
Deepwater packages of marine clastic sediment like the Martinsburg Formation are what alpine geologists call “flysch,” a word meaning essentially “mountain dandruff dumped in the sea next to the mountains.” (A companion term, “molasse,” translates to “mountain dandruff piled up on the land right next to the mountains.”)
Here’s a particularly coarse section (that is to say, it has lots of sand):
Here’s a particularly muddy section (i.e., dominated by finer-grained sediments):
These packages of clastic sediment frequently accumulated in graded beds, reflecting pulses of turbid, churning water cascading into the still water of the deep sea. As the energy dissipated, the heaviest (~largest) grains settled out first, followed by finer and finer particles. This produced graded beds, a characteristic primary sedimentary structure:
…A few of them:
A set of graded beds in a vertical orientation:
Later mountain-building (the late-Paleozoic Alleghanian Orogeny) squeezed these pre-existing strata, folding them into a massive regional down-warping called the Massanutten Synclinorium, but also imparting a tectonic cleavage. In the next photo, the strata are vertical, but the cleavage dips steeply to the lower right:
The cleavage is much more pronounced in the muddier portions of the turbidite, and less obvious in the sandier portions:
One more example:
Here’s a switch in perspective. Now we will look at the bedding plane itself, not a cross-section of it. In this next photo, our perspective is looking up through the uppermost parts of a lower graded bed (fine-grained scraps projecting from the outcrop face) and seeing into the very bottom-most parts of an upper graded bed (coarse-grained, more distant rock).
Here’s another bedding plane, this one bestrewn with graptolite fossils. We found this slab as float,
Here’s a GIGAmacro image I made of it, if you’d like to explore:
Link 1.38 Gpx GIGAmacro by Callan Bentley
Russ, a paleontologist, traced the fossil fragments uphill and found the stratum they originated from, in situ in the outcrop:
Another bedding plane, showing another fossil – but this time it’s trace fossils protruding as little nubs from the bottom of the overlying bed:
Another bedding plane feature we noticed were these excellent flute casts on the underside of one bed:
Annotated to show interpreted current flow direction with yellow arrows:
And there were other structures to be seen, too.
Here’s a neat example of closely spaced jointing, perpendicular to bedding in a silty package (atop a graywacke layer):
We also saw evidence of folding. Here’s one limb of an anticline:
… And then if we walked down the road to the right, we saw this:
Crudely, those fit together something like this:
Two outcrops showing different bedding/cleavage relationships, allowing the interpretation of a fold that’s larger than either outcrop, and a cleavage fan overprinting it.
All told, this was a day well spent. The rocks had diverse clues to offer up, and I was delighted to add these outcrops to my ‘mental map’ of the region’s geology.
15 March 2019
Following on the heels of his awesome fold photos from a few weeks ago, Chuck Bailey was kind enough to share another couple of Omani fold photos with us:
Great stuff. Thanks for sharing, Chuck.
Happy Friday, all.
8 March 2019
Today, we journey to the sky above the Swiss Alps, where Bernhard Edmaier took this stunning photo of the Dent de Morcles:
He reports that
The huge fold in the flank of the 2969 m high Dent de Morcles is the most impressive witness to the collision between Africa and Europe. The rock layers, originally deposited on the sea floor in a horizontal position, were compressed and shifted. The darker parts developed during the Tertiary period and are younger than the greyish and yellowish limestone of the Cretaceous period.
Here is another perspective on the same fold, but I like the one above because you can see that same recumbent syncline on the mountains in the background, in shadow. Here, I’ll trace it out:
You can correlate these outcrops through space, where erosion has removed most of the rock, like so:
It’s a spectacular example of a mountain-sized fold. Many thanks to Bernhard for sharing.
1 March 2019
Here’s a fold that rolled in a few weeks back, from reader Saranne Cessford, who writes:
Here’s my fold: Gold Harbour, South Georgia Island. Opposing recumbent fold noses frame the hanging glacier at Gold Harbour. Rocks are volcaniclastic turbidites of the early Cretaceous Cumberland Bay formation. The white dots along the shoreline are King penguins.
Let’s zoom in on the two “noses”…
Great looking rocks! The glacier and penguins ain’t bad either!
23 February 2019
Because of my commute, I consume multiple books at the same time. I listen to one in the car, and I read another (or more than one other) at home, on traditional paper. This past week, I read Jurassic Park, by Michael Crichton and listened to David Copperfield, by Charles Dickens. I chose the Dickens volume just to have something to listen to that wasn’t NPR coverage of our disastrous modern political era, and I chose Jurassic Park because my son is really into dinosaurs and fossils just now, and I remember it as a great novel. He’s getting an edited version, mind you, cleaned up of the nasty language and violence, as well as descriptions of the men ogling Ellie Satler’s legs. I remember Jurassic Park as being so vibrant and vital a story that (as a high school student and then as an undergraduate) I pressed it on everyone I knew with a scientific frame of mind.
But man, reading it now, in regular comparison with Dickens? Crichton sucks!
Crichton’s novels have always explored the scientific vanguard in the context of various human motives, some noble and some nefarious. They move fast, and are exciting. That holds a reader’s attention, but it’s soooooo different from Dickens, who plots his novels emphasizing character and time, and the beauty that emerges isn’t only in the twists of fate (of which there are several very satisfying ones) but in the details of the characters, in particular their dialogue, which is always distinctive and flavorful. To compare Wilkins Micawber to Uriah Heep to Aunt Betsey Trotwood is to encounter distinctive voices and characters, different essential personalities. In contrast, Crichton’s characters all sound like they speak with the same mouth; there is no nuance or idiosyncrasy. Even the chaos theorist Ian Malcolm, who I think is Crichton’s most distinctive character, is basically a speakerbox for Crichton’s own perspective, and he holds forth in long rants which might as well have been essays or “author’s note”s that Critchton wrote representing himself.
Both novels contain no major characters beyond white people. In Crichton’s book, it’s cringe-inducing to see that all the black characters are introduced as merely “a black man,” though of course none of the white characters are introduced as “a white man.” That they are white is just assumed in the Crichtonverse. The sole exception was geneticist Henry Wu, an Asian-American character. It was a good choice on the part of Steven Spielberg to cast Samuel L. Jackson as John Arnold in the movie version of Jurassic Park, injecting a jot of diversity into what was otherwise a lily-white cast. In another instance, Wu reflects on DNA being an ancient molecule, being present in microbes as well as “human beings, walking around in the streets of the modern world, bouncing their pink new babies.” Not all babies are pink, of course, and this I think reveals Crichton’s blindness to non-white people, his thoughtless racism. Of course, Dickens doesn’t feature any characters from non-European ancestry either, but he was writing in a much less diverse portion of spacetime. I can find it in my heart to excuse Dickens in a way that seems preposterous for a well-educated modern-day American like Crichton. In other words, the context of the novel’s setting and its author’s society are relevant in passing judgement on them. It is also worth noting that the latest film to be adapted from David Copperfield, due out this year, will feature a cast much more diverse than Dickens might have scripted.
Another set of thoughts: rereading Jurassic Park to my son reminded me of how much of my impression of that story had been (re)formed by watching (repeated, I’ll admit) screenings of the film adaptation. Spielberg ended up telling a story that I think was better in several key regards from the novel that inspired it, with (1) the dinosaurs restricted to the island only (the novel has them in mainland Costa Rica both first thing and last thing), and with (2) both Malcolm and Hammond surviving the story to fight another day, and (3) vice versa for Gennaro. Another useful change was (4) swapping the age structure of child characters Lex and Tim, with Lex attaining computer savvy and thus having a positive role to play in the resolution of the plot. In the book, she basically whines the whole time. I liked too how the film had Malcolm as more heroic and less scaredy-cat (5) when he grabbed a flare to distract the T. rex.
A final thought to this little missive: Dickens deserves his reputation for penning excellent literature, and listening to David Copperfield was an absolute delight. It’s an excellent story, and holds up well despite being more than 150 years old.
22 February 2019
Graham Andrews of West Virginia University has shared some images for today’s Friday fold. Graham reports that these photos show
the Miocene-aged Nuraxi tuff (rheomorphic lava-like ignimbrite) of Sardinia. The 1st 3 are syn-depositional:
Zooming in on the fold hinges, which are kind of subtle: these two close-ups show the folds to be very tight; pretty much isoclinal:
Roughly annotated to show the trace of the layering:
Graham notes that these small-scale syn-depositional folds are
refolded by really big folds like #4:
18 February 2019
Periodically, the administrators at my college will buy a lot of copies of a particular book, and then distribute them to the faculty as a way of sharing a useful resource or message. Generally, I find that I have other more urgent ways to spend my reading time: books about astronomy or rocks or ancient life or politics or philosophy. But this semester there are a couple of new variables that led me to open Ken Bain’s What the Best College Students Do. One is that I’ve gotten familiar with some educational research about study strategies – which are effective and which are a waste of time, and I’m communicating that to my students in hopes they will get more out of my classes. Also, for the first time I’m trying my hand at teaching a college skills class for freshmen, and so this title attracted me as a source of potential lessons for that course. This book is a sequel of sorts to a previous volume called What the Best College Teachers Do, which I reckon I’ll have to read next.
So what’s it all about? It’s basically a series of profiles of people who took charge of their learning, sharing their stories. It also includes nice readable summaries of empirical educational research studies that examine specific aspects of learning. Bain interviews Stephen Colbert and Neil Tyson, as well as MacArthur fellows, philanthropists, and innovators in many realms. The common thread is that these highly successful people found their inspiration, and let that guide a creative, engaged learning process, rather than seeking good grades or a compelling transcript. Attitude is key, in other words, as well as a conception of intelligence as an expandable commodity, rather than fixed state. They took risks and learned from their mistakes. They meta-cognitively embrace education as an athlete would train their body. Muscles aren’t fixed – they can be strengthened with exercise and training; and the successful exemplars in Bain’s book took a similar tack with developing their minds. Follow your deep curiosity, Bain advises, and find problems that need solving. Your mind can be expanded, and your value to the world will be enhanced if you realize your potential can peak if you work at it.
As a life-long learner, I found the book to be moderately inspiring, but not quite in the realm of “life-changing.” I wonder if a younger person might feel differently.
14 February 2019
Darrel Cowan, professor of geology at the University of Washington, is a frequent Friday Fold contributor. He pitches in today with a real show stopper:
In 2010, I was on the south coast of Sicily with my Italian colleague, Prof. Stefano Lugli, from the University of Modena. We spotted this fold, looking SE, in what is called the “upper gypsum” unit of the Messinian evaporatic strata. Stefano wrote me that the location is at Giallonardo close to Siculiana.
I present the structure as a fault-propagation fold, and in the second image I add my interpretation: the position of the fault changes from parallel to layering to where it ramps up and cuts across the footwall strata into the hinge of the syncline.
Callan again here. That looks right to me; the annotation presented here is my own, with the fault drawn as a solid black line parallel to layering, and dotted in black where it ramps up across the strata. I’ve opted for that annotation scheme because while the rock in the fault zone appears crushed up (resulting the one zone of relatively poor exposure), it doesn’t appear like there’s much offset along this fault yet. In other words, I see this as an incipient fault-propagation fold. If deformation were to proceed, I’d really expect that sequence of massive-bedded gypsum to show more displacement on either side of the fault.
The other thing Darrel alluded to but I think deserves to be expanded on is that this package of “Messinian evaporatic strata” is extraordinary as a stratigraphic phenomenon in its own right, regardless of whether it’s been folded. About 6 million years ago, the Strait of Gibraltar closed, preventing the waters of the Atlantic Ocean from mixing with the Mediterranean Sea. The climate over the Mediterranean is arid, and as the evaporation:replenishment ratio approached infinity, the sea dried up. All the solutes swimming around as ions in that seawater became more and more concentrated as the water evaporated, and they eventually precipitated out as layers of salt and gypsum and limestone. It’s an extraordinary event which basically transformed this sublime body of water into a hellish sort of mega-Dead-Sea landscape for a time. Wikipedia has a nice introductory summary here.
We can infer then, that the deformation that Darrel and Stefano observed in Sicily must be younger than the Messinian “Salinity Crisis,” as you can’t deform something until it’s first formed, and that means it’s less than 6 million years old. This is a very young fold, popping up out the landscape. It may well be that movement along the fault will fold it further in the future, and that offset I want to see will be there someday after an earthquake or two.