9 May 2017
The Foreknobs Formation is a Devonian unit in the Valley & Ridge province of the Mid-Atlantic Region. It was deposited in relatively shallow near-shore conditions during the Acadian Orogeny.
On a field trip to Corridor H, a new highway transecting the West Virginian Valley & Ridge province on Monday, I stopped to document a couple of beds showing very nice ripple marks.
These ones are symmetrical, and thus likely represent oscillating waves:
Here, two wave sets interfere with one another, amplifying and cancelling out each other’s bedforms:
Here’s a GigaPan of the scene:
Link 0.44 Gpx GigaPan by Callan Bentley
And here’s a 3D model:
5 May 2017
Digging into my photo archives for a suitably folded rock this fine Friday. Here’s what I came up with:
That has a very pleasing sinuosity to it, resembling drawings I made as a kid of sea monsters:
Those are folded limy mudrocks in Kootenay National Park, British Columbia, Canada. The prominent buckled layer is relatively pure limestone, with shalier strata above and below. I’ve featured folds from this outcrop previously here.
4 May 2017
Clarence King was a legend. He led one of the four great surveys of the American west (along with Wheeler, Powell, and Hayden) and eventually convinced Congress to establish One Survey To Rule Them All, an institution that ended up being called the United States Geological Survey. King was its first director, but he didn’t last too long in that position before resigning so he could pursue his own mining business ventures without any conflict of interest with his public position (hmmm). A biography of King might include his time in the California state survey, under Josiah Whitney. It would certainly include a re-telling of the famous Diamond Hoax that King helped uncover. And it would include tales of his convivial nature, an apparently legendary sort of extroversion. He was a gifted raconteur and conversationalist, and made friends of all he met. What might not get covered in as much detail is his extraordinary family life, a deceptive house of cards he carefully constructed and maintained, but which fell apart after his death. King pretended to be a black man (he “passed” for a light-skinned African American) and married a black woman, Ada Copeland, who had been born a slave just prior to the Civil War. King’s nom de mariage was “James Todd,” and so Ada became “Ada Todd,” assuming a last name she didn’t know was fiction. King traveled extensively for his work as a geologist, and basically lived out of hotels and clubs most of the time, except when he was home in New York, wherein he transformed into James Todd, home after a cross country journey as a railroad porter. He and Ada had a slew of children, some of whom survived and some of whom died young. When King contracted tuberculosis and died, he sent Ada a letter confessing his real name. He had influential friends provide modest, sustainable financial support to Ada and her children, who was now Ada King. Dependent on the money for the sake of her children, she kept relatively mum about the situation, but quietly pursued attempts to recover a trust fund that King had lied to her about. Eventually, three decades after Clarence King’s death, this culminated in a lawsuit that, while unsuccessful, brought the cross-racial marriage into the public awareness. Martha Sandweiss documents this surprising history in Passing Strange. I found the book to be compelling, well-paced, and astonishingly meticulously researched. It’s a fascinating look behind the curtain at one of the most famous American geologists, as well as an insightful examination of the state of race relations in the half century after the Civil War. Recommended.
3 May 2017
This morning, I riddled you this:
I got a few guesses on Twitter, none entered as comments on the blog, but a slew of hearty, enthusiastic conversation on Facebook. That’s where the people are, I guess. Many of them came up with great ideas to explain this odd scene of big angular rocks lying on top of what appears to be a “lawn” of grass…. Time to reveal what’s really going on!
It’s a marine terrace with a thick mattress of turf developed atop it.
…And as any four year old will notice, there are rocks lying all over the grass there!
This is a striking fact, because the grassy marine terrace is somewhere around 20 meters above sea level. As you walk toward the cliff from the grass (don’t get too close!), you see the source for these boulders and cobbles: bedrock of Eshaness volcanics.
Some force is removing big chunks of that rock and relocating them 10-20 meters inland from the grass’s edge, a bit inland itself from the rocky precipice.
What force could that be? Well, if you’ve visited the Grind of the Navir, you might be predisposed to think about storm waves – immense, ungodly powerful storm waves, crashing into the cliffs and climbing up, reaching up 60 feet above their base, and smashing out rocks, tumbling them inland as the wave energy dissipates.
Hard to see a grassy plateau dotted with rocks as a “beach,” but I think that’s what this sedimentary deposit qualifies as: a storm beach. The blocks of rock here aren’t as big as those at the Grind, nor as concentrated, but I think it’s reasonable to infer they are more recently deposited than the grass they lay atop. And therefore I think the origin is roughly the same.
Here’s another example we saw a few days later, from the Yesnaby region of Orkney (perspective is looking to the south):
It may not be a coincidence that all three of these locations are on west-facing coasts of their islands. Things must get pretty hairy here come wintertime.
2 May 2017
It’s getting to be full-on spring here in the Fort Valley. Everything which was winter brown is now spring green.
Everywhere I look, I see chlorophyll:
These eastern deciduous forests are busy gearing up for an astonishing feat: Together with their photosynthetic brethren across the northern hemisphere, they are getting ready to extract carbon dioxide (CO2) from the atmosphere and fuse it to water (H2O) pulled up through their roots to make glucose. In so doing, they disentangle atmospheric carbon from oxygen. They want the carbon, but they have no immediate need for the oxygen. There’s a surfeit of that stuff anyhow: they say, “Get rid of it!” Photosynthesis generates oxygen as a waste product, but it’s not the goal of the process. Inconsiderate plants dump it into the atmosphere without regard for how that reactive gas will impact other life on Earth (a bummer if you’re an anaerobic microbe, but it’s a major score for Animalia!).
The overall effect of this extraordinary ramping-up of photosynthetic activity can be seen in the concentration of the important atmospheric trace gas, CO2. Each boreal summer, its concentration drops by ~7 parts per million (ppm), drawn down by the greedy carbon-gulping of gazillions of green things: plants living on land and phytoplankton living in the water.
We can measure this effect. Examine the dashed red line in the graph below, from the CO2 monitoring station at Mauna Loa, a place far from huge concentrations of trees, as well as being remote from urban centers (that’s why they chose to stick the monitoring station there). Each year, the CO2 levels hit a high in the late boreal winter, and get drawn down to a minimum at the end of each boreal summer, when the trees are swollen with carbon extracted from the atmosphere, and seasonal photosynthesis draws to a close.
The black line in the graph shows what atmospheric CO2 levels would be if it weren’t for the seasonal cycle of photosynthesis turning on and turning off in the land-rich (and land-plant-rich) northern hemisphere. If there were no extra transfer of carbon from the Earth’s sedimentary rocks into the atmosphere, that black line wouldn’t have a slope; it would be horizontal on the graph. The further north you go, the further you are into the territory of the plants, and the greater the prominence of the seasonal signal. (if you click through to that graph, you’ll see that the range of seasonal variation is about 15 ppm at Point Barrow, Alaska, and about 1 ppm at the South Pole.)
As I gaze out on this sea of green, I marvel at the power of all these flappy green solar panels, these carbon sequestering units, each one responsible for yanking a handful of carbon atoms out of the atmospheric mix, sticking it down into the cellulose of the tree, where hopefully it will remain for some time. If not for this effect, there would be ~1% more CO2 in the atmosphere of the mid-latitudes, with the attendant heat-retention and ocean acidification properties for the planet. The summer trees in my yard save us from that!
Together with their green kin, they do what they can.
‘Tis the season for carbon sequestration here in North America. Gaze around you at the green gauze and contemplate the vital biogeochemistry at work.
1 May 2017
When a volcano erupts ash into the atmosphere, static charges in the eruptive plume can sometimes produce spectacular displays of lightning. Those same electrostatic charges, coupled with the presence of water vapor, can encourage the ash to clump together in small concentrically-layered orbs called accretionary lapilli. The individual lapillus grows by adding layers of new ash on its exterior. A hailstone forms through a similar process, though made of ice. Both hailstones and lapilli have a concentrically-zoned structure.
Here is a suite of accretionary lapilli images from the Msauli Chert, exposed in the Barberton Greenstone Belt, South Africa, a kilometer or so from the Swaziland border.
Sometime around 3334±3 million years ago, a volcano erupted somewhere. The ash rose into the atmosphere, with dusty bits glomming onto to one another to make lapilli. Eventually, carried downwind, the lapilli grew big enough that they settled out, raining down into the sea, piling up in granular layers on the seafloor. Later deposition covered and protected the lapilli, preserving them from erosion and weathering. 3.3 billion years passed, during which time they were lithified and uplifted. Sometime recently, the R40 road was constructed through Barberton Mountain Land, connecting the South African town of Barberton to Bulembu, Swaziland. A roadcut there exposes these ancient primary volcanic structures to the inquisitive eyes of visiting geologists.
28 April 2017
Happy Friday! Here are two more folds in gneisses of the Lewisian, in the North West Highlands of Scotland, near Tarbet.
27 April 2017
I got drawn in to a climate change discussion on Facebook last week. I’d been doing really well staying away from such things, but a friend specifically appealed to me for help addressing the issues with a video that has a strongly-expressed central geologic argument to support the position that ‘elevated atmospheric CO2 is a good thing.’ I may have been recruited to this task because of my work developing curriculum that teaches students to identify logical fallacies in discussions of climate science for the InTeGrate project.
Anyhow, since I took the time and effort to do it, I figured it might be useful to share the results of my analysis here.
Here’s the video:
And here is my logical analysis / critique of the video, focusing on identifying logical fallacies:
- There is a non sequitur argument presented at 1:00: that because organic life is based on carbon, therefore an excess amount of carbon dioxide in the atmosphere is not harmful. It doesn’t follow that that is true.
- Another is at 1:45, wherein he points out correctly that without greenhouse gases (he says CO2, but let’s be generous and assume he means all greenhouse gases) in the atmosphere, Earth would be a dead planet. That’s true – but it again doesn’t follow that a lot more of those gases would be a good thing. An analogy to help see the flaw in this argument: without water, we would die of dehydration. Therefore floods aren’t bad. It doesn’t follow. Ditto iodine: a little bit prevents goiter (good), therefore a lot must also be good (not true: it poisons you).
I’d also point out here that the presence of CO2 in a planetary atmosphere doesn’t guarantee life: Our neighbors, the dead planets Mars (atmosphere is 95.97% CO2) and Venus (atmosphere is 96.5% CO2) prove that point.
- At 1:58, he contrasts EPA’s labeling of CO2 as a “pollutant” with his own (valid) description of CO2 as “an essential ingredient for life.” These two are not mutually exclusive. It’s all about the dose. Yes, CO2 is essential for (most) life on our planet. Yes, it can still be a pollutant in spite of that. It’s all about the dose. It’s a category error.
- At 2:15, he says it’s misleading to describe the products of the C + O → CO2 reaction as “carbon emissions” because CO2 is not C. This seems to me to be one of those things that’s factually true but utterly beside the point. If we referred to them as “carbon dioxide emissions,” would that change anything about the essential aspects of the case? I like “carbon emissions” because I take a very carbon-cycle-based viewpoint of the issue. If you focus on the individual carbon atoms’ fates, you can see how they pass from one Earth reservoir (sedimentary rocks, plants/biosphere, atmosphere, ocean, mantle, etc.) to another. This is not something you could say is true of “carbon dioxide emissions.” Because of this, I find “carbon emissions” to be valid as a term describing what’s going on.
- He calls people like me CO2 “alarmists” at 2:40: I’d expect my freshmen geology students to be able to identify that as a classic ad hominem attack. That’s Latin for name-calling, without addressing the substance of the argument.
- This is a big one: As far as facts go, the geologic perspective is a good one. I appreciate the approach – but it’s certainly spun in a not-the-whole-truth sort of way. At 2:50, he points out that for much of Earth history, CO2 levels have been higher than they are today or have been in recent times (e.g. Pleistocene). This is true. We are currently living in an “icehouse” Earth as contrasted with a “hothouse” Earth (lacking glaciers, with higher sea levels, such as persisted during the Cretaceous). He gives the example of the Cambrian, with “10x” higher CO2 than today. He doesn’t mention the lower solar output then. One of the neat things about our planet is that as the sun has gotten brighter, greenhouse gas concentrations have generally declined, keeping us in a “Goldilocks zone” where water can be a liquid and thus life can exist. He says “We are currently living in a low CO2 era.” This is true for *the planet*, but it doesn’t follow that it’s true for *our species*. (In fact, CO2 levels have never been higher for the species Homo sapiens than they are today.) It also fails to address rates of change, a matter of critical importance for other less adaptable species that are our neighbors in the biosphere. He goes on to discuss actual greenhouses and CO2 fertilization. While it’s true that elevated atmospheric CO2 levels boost productivity, it does not follow that this is the end of the story, that a “pro” cannot also be a “con.” In addition, I would note: the CO2 fertilization effect (more efficient photosynthesis, extra resulting plant matter) is insufficient to remove all the anthropogenic CO2 (+9 gigatonnes C per year) from the atmosphere. That’s thought to result in an extra 3 Gt of C being pulled from the atmosphere annually, with another 2 Gt going into the oceans, resulting in a net atmospheric gain of 4 Gt per year. This NASA graphic makes the point well:
Feeding more people with more plants is good – a point made by our rose-colored glasses narrator – but it’s not as simple as that. The story doesn’t end with extra food. A more complete picture would also include farming land lost to desertification, soil lost to erosion, oceanic dead zones due to fertilization, coral reef losses due to bleaching (and attendant loss of nursery space for marine fish, another major source of human food). This focus on “more carrots in CO2 enriched greenhouses” intentionally distracts from a more complex reality. It’s cherry-picking of the first order. He cites satellite evidence of the ‘greening of the Earth.’ True: but again, it’s more complicated than that. Those same satellites detect declines in oceanic productivity and melting of glacial ice. Satellites are tools that measure reality. Reality has positive effects and negative ones, too. It’s dishonest to only focus on one.
- His conclusion: “We should celebrate CO2 as the giver of life that it is.” True! But it’s not logically inconsistent that we should also fear it if it gets out of balance. Consider whether this analogue argument makes sense: We should celebrate sodium as the atom which allows our muscles to contract! Therefore we should all consume 10 pounds of rock salt today. Sorry: Non sequitur: It does not follow. Ask your doctor is 10 pounds of NaCl is right for you!
(Ask your climate scientist if 410 ppm atmospheric CO2 is right for you.)
The narrator’s argument fails on numerous fronts, most particularly the implication that if something has positive effects it therefore cannot have negative effects too. Is there anything I missed?
My latest book review is of a cutting-edge new novel that describes our current political dystopia in excruciating detail… Just kidding!
Seriously: I was spurred to re-read Orwell”s 1984 after last November’s election, and the counterfactual customs of our new commander in chief. ‘Alternative facts’ have many precedents in history, but perhaps none are so purely crystallized as the fictional ones that appear in this novel. Orwell wrote 1984 in response to Stalinism in the Soviet Union, but it has lessons that could be applied to many times and places. It’s sort of timeless (ironic, consider the title is a date) for that reason. Much of 1984‘s Oceania setting isn’t a “perfect match” for modern day America, but I found a few threads the two have in common. First is surveillance – which we are almost always under in urban public places these days, and even in rural settings, there are satellite eyes watching from above. The road system is another network of digital observation. You could also throw in our computers and Smartphones, which access the internet and now thanks to the passage of Senate joint resolution 34 by the 115th Congress, your internet service provider is free to sell that information to interested buyers. I wonder what Orwell would think of this distinctly capitalist perversion of ‘Big Brother’ invading our privacy.
The aspect of the book which more clearly (p)reflects our current situation is the Trumpian habit of saying one thing, then turning around and saying the opposite, and denying the first statement exists at all. The current revisionism was anticipated by Orwell in a clever way, wherein once a fact is decided to be the “Party Line,” then it is deemed to have always been the Party Line, since the party is clearly perfect and has never been otherwise.
Oceania is at war with East Asia.
Oceania has always been at war with East Asia.
This switching and denying the switch is distinct from another strain of lying, which is the GOP’s favored strain of denying the existence of that which can be measured. That we have now installed this anti-empirical approach in a position of near-absolute power was my main motivation for marching for science last week.
Finally, there’s the “Two Minutes’ Hate” that party members in Orwell’s book are subjected to each morning, like a coffee break, but instead they are whipped into a frenzy of hatred by a propaganda film, driving them into an altered state of consciousness where they are almost insane with rage. It reminds me of the baiting and fomenting practiced by Alex Jones (Infowars), Breitbart, and the constantly-shifting medley of fake news websites. Delirious with anger, one character throws a book at the screen in 1984. In real life, someone shows up at a pizzeria with a semiautomatic rifle.
All in all, I didn’t find re-reading 1984 to be as apropos as I suspected it would be for the current situation. We don’t have “thoughtcrime” yet. But I’m glad I re-read it anyhow. It’s a classic for good reason.