Geology and Scrabble

I don’t play many on-line games, but ever since my mom and I joined Facebook, we’ve been going back and forth in a regular Lexulous game. Lexulous is a tile based word game, basically the same as Words with Friends or their originator, Scrabble. The specifics are a little different, but the main idea is that you get tiles, each with a different letter, and you use them you form words earning a yourself a score based on the letters you use and some special score spaces on the game board.

Being a geologist has actually worked in my favor during these games. Geology is one of those fields that comes with a whole new vocabulary. Not just normal words with different meanings (like young), but whole new words you have to get used to using, like aa, lahar, and pahoehoe. Sure you could find these by just browsing through a scrabble dictionary, but having them ready in your brain is a huge help.

To be a good scrabble word it has to be playable with typical scrabble tiles (7 in your hand plus a few you can link up to in standard scrabble) and acceptable in the scrabble dictionary. Here are some of my favorites, all acceptable in the official scrabble dictionary.

aa : a term for a blocky lava flow, aa is a low point word but one of those vowel-iferous two-letter words that can come in handy as a hitching post.

pahoehoe : a term for ropy lava, another good use of vowels and the two h-tiles. Not a bad scorer either, with 2 h’s and a p.

cwm : amaze and annoy your opponents by playing cwm. In addition to being an unfamiliar term, it is also a weird looking word made of three high point letters.

apatite : no I didn’t spell appetite incorrectly, but like many mineral names, apatite (a hexagonal calcium phosphate and common accessory mineral) is acceptable.

sphene : Good to see that the Scrabble people don’t consider sphene to be discredited.

zircon : Z-words are always dicey. I use za too often, and rarely have the blank tile needed to make jazz. I also hate holding on to c’s, since there are no 2-letter c words. I’ll stop with the mineral names here, many of them are accepted, but I am only listing the best minerals.

aeolian : goofy spelling, but a wonderful vowel dump, the more common eolian is also accepted.

aeon : Another olde timey spelling, with eon also accepted.

oolith : oolite and ooliths also great, ooid isn’t though, which is just weird.

alluvial : alluvia also accepted.

karst : I am guessing sinkhole is also OK.

amygdule : I’ve never been able to play this one, but I’ve been close, and every time I see get a g and an m I am hopeful.

arete : Scrabble takes this even when you can’t use the circumflexe accent. I just googled what the little hat over the e was, by the way.

arenite : Not all sedimentary rock modifiers are accepted. Foraminiferous, for example, although unlikely, doesn’t work.

breccia : A word with 2 c’s! Sign me up.

boudin : The scrabble dictionary thinks this is a spicy cajun sausage but we all know it is a sausage-like structure formed from necking in a bed.

esker : One of my favorite glacial features, I like to say this word with a New England accent. Same with iron oxide, much more enjoyable that way.

rheology : Lots of letters, but if you can borrow one from another word it a solid bingo.

Let’s Call a Denier a Denier

***Update – In a huge win for everyone who isn’t a doofus, the AP has now officially changed the language it will use to refer to people who don’t accept modern science. From the AP blog:

To describe those who don’t accept climate science or dispute the world is warming from man-made forces, use climate change doubters or those who reject mainstream climate science. Avoid use of skeptics or deniers.

On the Media and other media critics have raised questions about the AP’s decision to avoid the word denier, and while I still prefer that word I am thrilled that they (and those who use their style guide) will no longer use the word skeptic. Overall a win for the good guys.

Much of today’s new media is dreadful – this is a truth well acknowledged by most of us in academia. Be it the doofuses who get to pass as “experts”, the prioritization of special-interest and feel-good pieces, the pushing or corporate agendas, or the general lack of self-reflexive insight, very few of us feel that we ever really learn that much from the major news networks. The one large organization often excepted from this criticism is NPR*, probably the most pre-programmed radio station in every faculty and staff parking lot at your local college or university. NPR can do some great journalism and story-telling, if you can get past it’s east-coast upper-middle class view of the world, and it is the only major news outlet that I can stomach for extended periods of time.

Perhaps this is what I got so annoyed the other morning. Usually I am either biking or bussing to work in the morning, but that day I had to drop my folks off at the airport bus station and had a few hours in the car. Morning Edition, the normal NPR offering this time of day, was doing a piece on President Obama’s upcoming trip to Alaska, and his renaming of Mt. McKinley back to Denali. The trip is thought to focus on the effects of climate change, which is excellent, which lead the Morning Edition host Steve Inskeep to say the following:

Climate is the president’s main focus on this trip, and on that subject, in Alaska, climate skeptics and environmentalists alike question the president. John Ryan reports from our member station KUCB in the Aleutian Islands. (full transcript here)

You can probably tell by the words I highlighted in the above quote that my problem with this statement is the term “climate skeptic.” This term is used regularly, every week or so I put on my grumpy old man pants and fire off an email to some editor or ombudsman about their use of this term (for example here on CNN). I expect most of these outlets to use the term, but NPR’s use of it got me sufficiently grumpy that I thought I’d write a post instead. There have apparently been hints that NPR had stopped using this incorrect term back in 2014, but apparently not all of the script writers got the message.

Skeptics are great, they question prevailing wisdom; they collect data and observations and then use reason, logic, and critical thinking to come to a conclusion. Basically they follow where the data and observations lead them, even if it is into uncomfortable or unpopular territory. Importantly, skeptics should be ruled by reason. The ideal scientist (or academic generally) is skeptical, sure we all have biases, but every interaction with data is an opportunity to challenge ourselves.

Refusing to accept ideas in the face of overwhelming evidence is not skepticism, it is denial. There is no such thing as a round earth skeptic, heliocentric solar system skeptic, or anthropogenic climate change skeptic. People unwilling to accept the overwhelming evidence are deniers, and we need to call them that.

The truth is, good scientists welcome skepticism. Think of Richard Muller, one of the few who might have fallen into the category of skeptic (although one could argue his old position required a general ignorance of climate science considering that most of his points of contention had been addressed by the climate science community previously). Anyways, he challenged the prevailing science, took some money from the Koch Brothers, collected data, thought about it logically, used reason, and realized the climate scientists were right all along (read about it here). That is what a skeptic would do, and regardless of his original position, at least Muller can be given credit for doing his due diligence.

This is a long winded way of saying that language is important, and the term “skeptic,” when applied to climate change deniers (or evolution deniers or ancient earth deniers or whatever) gives them undeserved credit and makes them sound like they are acting rationally and basing their position on the preponderance of evidence. They are not, and we need to call out the news organizations that continue to prop them up. For fuchsite sake 14 of the 15 warmest years ever recorded have occurred since 2000, with the 15th being 1998, people born after 1977 have never experienced a year cooler than the 20th century average, and anyone born after February of 1985 has never experienced a single month colder than the 20th century average.

So the next time you hear a journalist refer to someone as a climate skeptic, put on your old person grumpy pants, fire up the complaint letter emails, and remind them that climate deniers belong in the same bin as flat earthers.

*I am using the term “NPR” as a catch-all for public radio, although I know that the details of who produces the program can vary. I’ll refer you to this story from On the Media if you are interested.

All Salt is Sea Salt

Check it out, SEA SALT!

OK I’ll put an asterisk in the title because I suppose some salt can come from dried up lake beds but really, doesn’t this drive other geologists nuts?

This afternoon I was following a recipe that suggested I use Himalayan Sea Salt because normal table salt is apparently bland and from a lab and totally unhealthy and carcinogenic or something. According to a few minutes of self righteous and annoyed googling I’ve found that some people define sea salt as salt produced directly from evaporating sea water (modern day) but that doesn’t explain the 20$ a pound “Himalayan Sea Salt” unless of course someone found some Tethyan water laying around. Salt that is mined, be it in Utah or Michigan or Poland or wherever exists in large deposits formed by the evaporation of sea water, often tens to hundreds of  millions of years ago… you know, SEA SALT. Road salt is sea salt, Safeway salt is sea salt, all salt is sea salt! It seems like Lake Salt would actually be a more useful fancy identifier, I am sure there are some salt deposits in lake beds that can be mined. Next foodie craze, LAKE SALT!

Oh but Himalayan Sea Salt is all natural and pink so it must be better….It is pink because it contains Iron Oxide, you know, RUST. If you want some rust just stop drying your cast iron pan for a bit, BOOM, I just saved you 20$ a pound on pink salt. And guess what, Himalayan Sea Salt is also mined from evaporite deposits, just like all of the other salt you buy. Neither one is healthier, they are essentially identical from a nutritional point of view which of course makes sense since they are the same damn thing.

I am naturally suspect of many foodie claims but I highly doubt that anyone has a refined enough palate to pass a double blind taste test.

We secretly switched the bland generic Morton salt Thermochronic used to make scrambled eggs with 20$ a pound pink Himalayan Sea Salt…..

And even if you can, can’t you think of a more descriptive name? What is next, water-ice? You know, when I wrote that last sentence I thought it was going to sound totally absurd but then I remembered that people actually buy bottled water from Fiji, on purpose, so never mind.

I understand that the shape and texture of the salt can be important, and sure maybe you want to avoid anti-caking agents for some questionable reason, this is why I also have coarse salt on hand, but it’s origin is all the same, the ocean. Sea Salt can join the list of other made-up identifiers like Corinthian Leather designed to make people pay lots more for the same crap.

Climbing Up the Middle of a Pluton

I am by no means a climber, but I love rocks and have a great appreciation for people who choose to spend hours and hours with their faces inches away from rocks. I have climbed a few times, and I really got a kick out of how much attention I paid to changes in lithology, bedding, and grain size (THANK GOD A PEGMATITE!). As someone who pays attention to outdoorsy writing I found myself following the recent (successful) attempt to climb the Dawn Wall of El Capitan in Yosemite. The imagery is amazing at so many scales, the far away views of course but the close ups as well that highlight how pitiful the handholds are that Tommy Caldwell and Kevin Jorgeson both found and used to climb. Anyways, I found myself watching a wonderful Earth Porn video of some of the climb and thinking about another stupendous El Capitan related piece of work that was recently completed. This was a detailed geologic map of El Capitan made and published by Roger Putnam. Putnam also spent hours and hours high above the valley floor studying the rocks, but he also took samples, detailed notes, and compiled all of this work and information into a unique geologic map. Importantly, it is one of the best views we have of what the guts of a pluton look like. That is after all what people are climbing in Yosemite, the different colors and variations in rock type are the result of complex magma chamber processes happening miles underground over geologic time scales.

Well, in honor of the climb, the Geological Society of American announced a sale on the geologic map today, and I thought it would be useful to mention them both. Enjoy!

Screenshot of the geologic map of El Capitan from a great National Geographic piece with a sliding map feature.

The Heartland Institute: Comically Ignorant Poop Factory or Greedy Lying Dumbasses?

Ignorance is the fifth horseman of the apocalypse. In many ways it should be the main one, seeing as it is ignorance that is the root cause of so much of the evils assigned to the better-known four. I am not of course talking about people who are uninformed, I mean instead the sort of willful ignorance and anti-intellectualism that is unfortunately so common. It is the people with the resources to learn but who decide to remain rooted in myth and ideology, the ones who refuse to alter their positions or even admit complexity when confronted with logic, reason and evidence who are the true ignorants. These people are terrible and unfortunately often put in positions of influence. This brief lament of willful ignorance is a wonderful set up for a post about the Heartland “Institute.”

The continued existence of the Heartland Institute is one of those sad facts that gives me little hope for the future of humanity. Their idiocy and ignorance is epic, and they have historically taken whatever ill-informed position they feel will either fatten their bank accounts or reinforce their blind ideology the most. Their economic positions are dumb, but even this ass-hattery pales in comparison to the outright buffoonery and comically ignorant positions on science and the environment. The science team at the “Institute” would have a hard time passing a high school science class, and often puts out statements and opinion pieces that make The Onion seem reliable. Anyone who has followed the politics of different environmental and scientific debates has undoubtably, and unfortunately, come across this group, their stupidity is the unavoidable background blabber of public discourse, but sometimes they out-do even themselves.

Enter the Heartland Institute’s recent Climate Change direct mail campaign. I only saw this because they decided to send a stool sample (mailer) to a faculty member of the Earth Science department where I work, and s/he left this turd in the mailroom recycling bin. Maybe this shows their conviction, but for people like me who have a hard time envisioning anyone actually buys their propaganda, including the idiots producing it, I have to wonder. Anyways, this entire flier was so full of dumbassery, I decided I should share.

Before I start, I’d like to remind us that not accepting the reality of anthropogenic climate change requires one to be either ignorant or untruthful, neither of which are desirable traits in people wanting to lead or make policy. Those are the only two options. You can be skeptical, but skepticism is still rooted in evidence and logic, and those are both firmly on the side of the scientific consensus position, as has been demonstrated time and time again. Climate “skeptics” are actually science deniers, people who hold on to a provably wrong position despite overwhelming evidence to the contrary, and in my mind are grouped with the anti-vaccine crowd and the people who think the moon landing was faked. Their complaints are so predictable that you can debunk them with a  twitter-bot. I won’t link to all of the science here, but if you are interested please try my primers on teaching climate science here here and here.

So let’s take a look at this fecal masterpiece.

The cover art attempts to hypnotize the unsuspecting recipient and disconnect their brain from all centers of reason. This allows for them to paste random untruths, exaggerations, and lies, and make them sound true and scary, when in all likelihood they were divined via Ouija board or by summoning the ghosts of Ayn Rand and Ronald Reagan and asking them to make up more shit.

Here we get our first glimpse of some of Fartland’s strategy (I know it is a sophomoric joke but it fits and helps illustrate the reality of the smelly mess Heartland emits). On this page they try to set themselves up as an authority on climate science. They start by advertising their “conferences” which appear to be held yearly-ish. For those of you who attend scientific conferences, this format might be a tad bit odd. For example, they don’t appear to have many scientists presenting new data, the hallmark of actual scientific conferences. They have featured a science-denying Austrian rapper, you know, to reach out to the millennials, and to be fair it only costs $129 to attend, but calling this a conference is a bit of a stretch. From what I’ve been able to watch (it takes a strong stomach), it is the same string of oddly selective data and out of context graphs, figures with no axis labels, weird anecdotes, and obvious misunderstandings that plague all denier websites. No new science, no serious discussion, just poop. Not a conference, but a pep rally for ignorance.

I can actually understand why some people buy this. Science can be confusing enough and nit-picky enough that if you are truly on the fence you assume that these people are actually experts, or at least not liars. Not everyone is lucky like me to have been able to spend their life in science.

The “research” they advertise focuses on Fartland publications that are meant to look as much as possible like the IPCC reports. This Nongovernmental International Panel has been easily debunked many times, mainly because it is full of crap and fantasy. In addition though, I have to wonder if Fartland is even trying anymore? The claims they make in this book are the same dumb points they make that anyone with a passing knowledge of physical science can easily refute. CO2 is good for plants, science is never settled, blah blah blah. All distortions, misconceptions, or pure horse dookie. And for the love of God, everything they claim has been debunked SO MANY TIMES ALREADY.

For a group that complains about alarmists they sure aren’t shy of the scare tactics. Oh, and I think the boxer is a reminder that the Institute’s positions only makes sense to people with severe brain damage. The “What You Should Know” is a list of things that are just wrong and again, easily refuted. Interestingly you see here their strategy of “climate change isn’t real but if it is it’s good for us.” Also two things that aren’t correct.

So the main spread of the mailer is this centerfold of “experts” who disagree with the scientific consensus. Although even 40 or 50 people would be nothing compared to 97% of all climate scientists and every major scientific society that agrees with the central findings of the IPCC, as well as all published science in peer-reviewed journals, it is important to note that very few of these people featured in this spread are actually scientists, even fewer of them climate scientists. There is Chief Doofus Fred Singer of course, who is famous for being on the wrong side of every scientific debate he has ever waded in to, including his continued assertion that secondhand smoke isn’t unhealthy (go ahead parents, close those windows and light up!) He is the Nick Cage of the anti-science crowd, pay him enough and he’ll show up to anything (seriously, the Left Behind movie?). Apparently at one point in his life he was some sort of physicist, but he has demonstrated repeatedly his basic ignorance of other scientific fields in which he was never trained. Most of the people listed here would be better defined as “self proclaimed experts,” based on their lack of training and background.

You also see a lot of “Ph.D’s” on the list. Although Ph.D’s are hard to get, I don’t think a Ph.D. in immunology prepares you to handle climate science, just like I shouldn’t be designing vaccines. There are also a lot of economists and pundits, which don’t really count as science experts. I started going down the rabbit hole of googling some of these people, found some links about defending young-earth creationism and some other gems, but honestly that isn’t the point. The main point is that if you have valid scientific arguments then make them in peer-reviewed journals. If you articles aren’t being accepted, then put them out yourself and defend the science. Stop knit-picking, stop misleading, just present your fricking science. Not in a debate (we see how well presidential debates allow for actual discussion), but in a well-reasoned and defendable scientific paper. The literature Fartland does produce is so easily refuted that the only reasonable conclusion is that they have no valid scientific arguments. Likewise the talks I’ve suffered through on YouTube from their conferences are the same old predictable and incorrect junk, anecdotes, figures out of context, misleading statements, and exaggerations.

What these “experts” do seem to have in common though is an association with anti-government free-enterprise groups. Not my cup of tea, but of course your political or economic philosophies should have no bearing on whether or not you accept realities. There is no libertarian position on gravity, for example, or socialist version of relativity. This reminds me of a central point made by Naomi Oreskes in her fantastic book Merchants of Doubt, namely that many deniers refuse to accept the obvious science because they fear that the only solutions would require government actions, and that goes against their belief that the free market fixes everything. I don’t know if the only solutions come from the government, but the consistent alignment of science deniers with free market worshippers is undeniable.

The back of the poophlet (poop pamphlet, a wonderful term I just coined) is one of the best misleading graphics of all. The column on the left are all things that don’t matter or just aren’t true, nothing new for Fartland. The graphic on the right though implies that Al Gore and Barack Obama have something to do with climate science. Of course they don’t, they happen to be reasonably intelligent people who know that when decades of research and 97% of a scientific community comes to a conclusion, that it is reasonable to take action. Willie Soon and Robert Carter might be scientists, but they certainly don’t represent the scientific community (in the same way Fred Singer didn’t represent the scientific community when he claimed that the evidence for cigarettes being harmful wasn’t conclusive). Carter in fact has a history of making obviously wrong and misleading statements about climate change and CO2, including the old denier standbys “it’s cooling” and “CO2 is plant food” (see a list here). Soon has had a few ventures into climate science publishing but has not managed to make any claims that actually stick, and has not successfully rebutted the critiques of his published work. He has received a great deal of funding from the Koch brothers, petroleum and coal interests, which in itself proves nothing, but combine that with his lack of defendable science, and well you can see why he is in the tiny minority amongst climate scientists. Regardless, a proper graphic would show Soon, Carter, and one other denier amongst a field of 97 climate scientists with strong publication records.

Incidentally, I teach the “Al Gore” test. If you are ever debating climate change and someone brings up “Al Gore” they are admitting that they don’t know anything about science, and are instead letting their dislike for a politician guide their decision making process. It makes as much sense as telling kids to do drugs because you disliked Nancy Reagan. If you watch the Fartland conference talks or listen to deniers more generally and take a drink every time someone mentions “Al Gore” you will be drunk quickly enough to avoid the pain of watching the rest of the talks. So perhaps that is a good thing?

In summary, I feel bad for the tree that had to die to make this flier, it deserved better, and would have been covered in less poop had it been turned into toilet paper. I think I can answer the question posed in the title of this post by substituting in “and/or.”

Reflections on Thermo 2014 in Chamonix

I know that meetings are different from vacations. Meetings are busy, and even when they are in fantastic places, you rarely see more than the convention center and a few restaurants within walking distance. In addition, you usually don’t get to travel with your significant other, and sometimes share a hotel room with way too many people.

The bi-annual thermochronology meetings have always stood out for me though. I’ve been to 3 now, Anchorage in 2008, Glasgow in 2010, and now Chamonix in 2014 (China 2012 happened when I was fresh off 2 years of adjunct wages and had no funding). While I still share crowded hotel rooms and can’t bring my wife, I have had a chance to actually explore the host locales. In part this is because I’ve managed to go on the pre-meeting field trips for all three of these conferences, and in part because the conference itself includes a field trip day in the middle. But the meetings are also just unique, very different in feel from a big GSA or an enormous AGU. Also, the locations themselves have been in fantastic places.

So Chamonix was superb, the science, the location, and the organization. I thought I’d write up a few reflections and intersperse them with a random collection of pictures. Why not?

Panoramic view from the pre-meeting field trip in the French Alps.

The meeting structure was slightly different this year, and I thought it was excellent. Basically the organizers reduced the number of talks, increased the number of posters, and actually gave us time to see the posters. In addition, there were a series of panel discussions in the afternoons that covered a whole host of topics, the types of things the community needs to discuss, but for which you’d never find time to talk about at an AGU. In some cases this is airing dirty laundry, in others it was attempts to organize the community, but all of them were informative. And, because of the scheduling, I was able to attend and still have time to see the posters.

The terrible no-good rotten view I had to endure from the balcony of my hotel room. To add insult to injury, there was a rushing river just below my window so I had to put up with relaxing nature sounds. If you are in Chamonix, I recommend the Hotel Alpine, surprisingly affordable.

Most of the talks were excellent, and since there weren’t too many of them, I never slipped into that “holy shit I can’t believe there are 4 more talks until a break I should have sat closer to the door” haze, and I never had talks that I considered skipping. So what were some of the things I learned? Good question.

The meeting room inside the Chamonix-Mont Black Congress Center. The only downside of this set up is that when you are talking you can’t see your slides, and if you turned to look at your slides you moved too far away from the microphone for people to hear.

John Garver gave a talk about some of the work he’s been doing on zircon fission-track and (U-Th)/He dating. He’s been working on Alaskan tectonics for years, and has amassed an enormous data set from some of the rocks that record the approach and collision of different terranes. What piqued my interest though was his discussion of radiation damage in zircon. We know it effects He retentivity, and he’s started using a Raman spectrometer to quantify damage. I’ll let you read his papers to see his conclusion, but he made a very important point that has stuck with me. Annealing radiation damage in zircons requires amphibolite facies conditions. This kind of blew my mind. Although we have good experimentally determined models for radiation damage annealing in apatite, zircon appears to be a slightly different beast.

Lunch stop in the French Alps on our way to Italy.

Rod Brown discussed some of his group’s recent work looking at the effects of apatite grain fragmentation on He dates. He and his colleagues have two papers out on the subject, but he went through the numerical experiments in detail and demonstrated how proper characterization of fragmented grains can actually be seen as a feature of He dating in a way analogous to radiation damage, recording meaningful geologic information. While discussing this he introduced my new favorite term for He data sets with a spread in dates, beautifully dispersed.

Gran Paradiso national park in Italy.

This meeting was the first time that I felt like I started to understand the numerical models people have started devising to simulate He diffusion through crystal lattices. These are supercomputer-scale simulations meant to explore different controls on He diffusivity without inferring properties from in-vacuo diffusion experiments. Both Laurent Tasson-got and Cécile Gautheron talked about some of their models, and discussed why these models tend not to agree with laboratory based diffusion experiments. I felt like I at least now can revisit their papers and understand them a bit better.

Glacier and associated debris on the south side of the Mont Blanc massif, just before we drove through a long-ass tunnel back into France.

Rich Ketcham, senior member of the secret high council of super-thermochronologists, is organizing an inter-laboratory He collaboration. This is awesome, I am participating, and I hope I am not the outlier.

View of Chamonix from Aiguille du Midi after a terrifying 20 minute cable car ride during which I successfully managed to not crap my pants. The triangle shadow on the left is from mont Blanc, and conference center is one of the big white buildings.

I think my favorite talk of the conference was by Ryan McKeon. It had become apparent to me that most people at the conference trust their techniques more than anyone else’s. The fission-track people, for example, tend to be fairly suspicious of (U-Th)/He data (especially when it conflicts with fission-track data). What Ryan McKeon did is actually make sense of an exceedingly complicated data set, and for me showed that we understand  the controls of He diffusivity rather well, we just can’t characterize our samples in enough detail. He did, he spent a ton of time (a serious boatload) characterizing the apatites in this difficult data set and was actually able to explain his data using existing models of radiation damage and He diffusivity. This was heartening for me, it requires a ton of work but suggests that we understand things better than we can routinely characterize them.

A group of alpinists who took the cable car up Aiguille du Midi wait to head down a western ridge and explore the high alps. The cable car ride is interesting in part because half of the passengers are wearing crampons and carrying ice axes.

One thing I learned, coffee in France isn’t that great. They are obsessed with these automatic Keurig-style machines that specialize in overpriced mediocrity. I honestly don’t think I saw a coffee grinder the whole time I was in France. We did stop in Italy for coffee where a super efficient barista ground and pulled a few dozen espressos for the group within a shockingly short period of time. But not in France. Weird, for a people so into cuisine the coffee was disappointing. This did allow me to develop a new back-up plan of opening a high-end coffee shop in Chamonix. The baked goods and cheese were excellent as expected, as was the chocolate.

View from the cable car south to the intermediate station and down to Chamonix. You can see why I am impressed that I managed to not crap my pants.

There were also tons of excellent posters that used thermochronology to address geologic questions. Too many to list, and my notes are crappy enough that I wouldn’t properly identify the authors, but needless to say the future thermochronologists of the world are an impressive bunch.

The cable car leaving the midway station and heading up to the peak.

There was a general agreement that experimentalists need to do more experiments, but of course it is easy for people like me to tell other people they need to do more work. I am actually quite good at that.

What is left of Mer de Glace, a glacier north of Chamonix. The trim line was filled with ice in the early part of the century.

Hopefully I’ll be heading to the next Thermo meeting in Brazil (2016). After that we are in Germany (2018), and then back in the U.S. somewhere in 2020. They are easily my favorite meetings, much more of a positive experience than the big ones, so now I just need to do some science so I have something to present! I can also hope that the Germany meeting lines up with the Bundesliga season, that would be excellent.

Hiking down to Mer de Glace they have these signs posted showing where the ice was at different recent time periods. Here we are at when I started high school in 1990. Yup, all that melting in just a few decades.

He Thermochronology Reading List

I was always jealous of geoscientists who started their education in the 70’s; for them, there was only a 10 year backlog of plate tectonics relevant geoscience literature to catch up with. Even under sane circumstances it gets harder and harder every year to catch up on all of the relevant literature, but multiply the level of difficulty by the proliferation of academic journals and the ever increasing push to publish, and you can see the inherent problem for any student looking into a subject with more than a decade of science behind it. If you are lucky there are a a handful of key papers that some older student or generous advisor tells you to start with, but more often you spend most of your graduate career writing down references you are embarrassed not to have read.

From a (U-Th)/He perspective I hit things at the right time. The first modern He paper was Peter Zeitler’s 1987 paper U-Th-He dating of apatite: A potential thermochronometer published in Geochmica et Cosmochimica Acta (v. 51, no. 10, p. 2865–2868), and by my first day of graduate school in 1999 publication was modest enough that I could carry every single modern (U-Th)/He paper around in my backpack (which I did, a sort of penance for not having read and re-read them enough times).

Being near the beginning makes it easier to keep up, but it of course also allows one to develop a historical view of the development of a field. When you are reading papers as they come out, publication in 1999 and 2001 is a huge gulf, but when you are downloading PDF’s in 2014, you can often forget the relative order of the work and not entirely grasp the timeliness and importance of an individual contribution. There is also the critical viewpoint you get from attending meetings and seeing early versions of the studies, something that scanning abstracts cannot give you.

Anyways, my point is that when people start working in my group on He projects, they often begin at Outcrop #1 (I was taught that this was the library but I now assume it is google scholar). Probably the hardest thing about doing a M.Sc. is trying to read enough to know the field and have enough time to do your own work. So I am often asked about what papers you should read to get up to speed. Well, no list is perfect, but I thought why not put this up on the World’s Leading Thermochronology blog? Perhaps other techniques and subdisciplines will follow, but here it goes. My essential beginner (U-Th)/He reading list. Oh, and I am sticking to academic papers, but I’ll throw out quick references to my earlier post just for the über-beginner.

As a disclaimer, this list is obviously not exhaustive or complete. Nor is it a list of what I consider to be the best papers in the field, in fact some of the ones I consider to be the best do not appear below. What I am trying to compile is simply a primer, with minor annotations, in chronological order, of papers that seem to get referenced and discussed often. The might be milestones, or they might provide some important summary or lesson that most He chronologists take as assumed knowledge. I am also not providing PDF’s or links to PDF’s because I am not an idiot and refuse to fight Elsevier’s legal team. I am putting them in chronological order to help preserve some sense of the historical development of the technique, and please, if I forgot something, email me!

Zeitler, P.K., Herczeg, A.L., McDougall, I., and Honda, M., 1987, U-Th-He dating of apatite: A potential thermochronometer: Geochmica et Cosmochimica Acta, v. 51, no. 10, p. 2865–2868. The paper that started it all, a revisitation of a long-forgotten technique within the context of modern thermochronology and noble-gas diffusion.

Farley, K.A., Wolf, R., and Silver, L., 1996, The effects of long alpha-stopping distances on (U-Th)/He ages: Geochmica et Cosmochimica Acta, v. 60, no. 21, p. 4223–4229. One of the foundational papers that explains and provides a solution for alpha-particle ejection, one of the fundamental problems in He dating. The methods have been modified, but this paper sets the bar.

Wolf, R., Farley, K.A., and Silver, L., 1996, Helium diffusion and low-temperature thermochronometry of apatite: Geochmica et Cosmochimica Acta, v. 60, no. 21, p. 4231–4240. Wolf’s Ph.D. thesis laid much of the foundation for He dating, and this paper provides some of the first high-quality diffusion data for apatite.

House, M.A., Wernicke, B.P., and Farley, K.A., 1998, Dating topography of the Sierra Nevada, California, using apatite (U–Th)/He ages: Nature, v. 396, no. 6706, p. 66–69. He dating has the power to date processes that occur at very low temperatures, and this paper decided to swing for the fences and use He to address landscape evolution in a consistently contentious region.

Wolf, R., Farley, K.A., and Kass, D., 1998, Modeling of the temperature sensitivity of the apatite (U-Th)/He thermochronometer: Chemical Geology, v. 148, no. 1-2, p. 105–114. Like all thermochronometers, He dates are non-unique, and represent the integrated thermal history of a particular grain. This paper explains the fundamental math of this reality, and provides some very clear and straightforward examples of how this can cause practical issues.

House, M., Farley, K.A., and Kohn, B., 1999, An empirical test of helium diffusion in apatite: borehole data from the Otway basin, Australia: Earth and Planetary Science Letters, v. 170, no. 4, p. 463–474. Otway basin is a key natural calibration location for the apatite fission-track system, and this paper used the well-calibrated drill-hole to test if the laboratory diffusion studies made sense. Spoiler alert, they do.

House, M.A., Farley, K.A., and Stockli, D., 2000, Helium chronometry of apatite and titanite using Nd-YAG laser heating: Earth and Planetary Science Letters, v. 183, no. 3, p. 365–368. Early He dating was done with multiple grain aliquots in resistance furnace, this took a ton of time and required lots of material. This paper solves the laser heating problems and led to the modern age of regular single-grain dates.

Stockli, D., Farley, K.A., and Dumitru, T., 2000, Calibration of the apatite (U-Th)/He thermochronometer on an exhumed fault block, White Mountains, California: Geology, v. 28, no. 11, p. 983. If you’ve ever wondered what a perfect He data set looks like, here you go. I am convinced that this paper sold more He labs than anything else because it made the technique look easy and powerful. Figures from this paper are still amongst my favorites for demonstrating the technique, and I’ve found it to be a fantastic reading group paper for beginner thermochronologists. You can discuss and demonstrate many key aspects of He dating in a relatively short paper.

Farley, K.A., 2002, (U-Th)/He Dating: Techniques, Calibrations, and Applications: Reviews in Mineralogy and Geochemistry, v. 47, no. 1, p. 819–844, doi: 10.2138/rmg.2002.47.18. This review paper is superb, readable, relatively comprehensive, and exceedingly useful.

Meesters, A., and Dunai, T., 2002, Solving the production–diffusion equation for finite diffusion domains of various shapes Part I. Implications for low-temperature (U–Th)/He thermochronology: Chemical Geology, v. 186, no. 3-4, p. 333–344. Kind of a “deep cut” for people interested in diffusion, this paper helped teach me more about the mathematics of He diffusion than damn near anything.

Shuster, D.L., Ehlers, T., Rusmoren, M., and Farley, K.A., 2005, Rapid glacial erosion at 1.8 Ma revealed by 4He/3He thermochronometry: Science, v. 310, no. 5754, p. 1668. 4He/3He thermochronology is a powerful technique on its own, but it also helps address and investigate a variety of issues in “traditional” He dating. This paper provides a good introduction to the technique and helps show off its potential, and can serve as an amuse-bouche for the beefier (or tofu-ier for some of us) 4He/3He literature.

Fitzgerald, P.G., Baldwin, S.L., Webb, L., and O’Sullivan, P., 2006, Interpretation of (U–Th)/He single grain ages from slowly cooled crustal terranes: a case study from the Transantarctic Mountains of southern Victoria Land: Chemical Geology, v. 225, no. 1-2, p. 91–120. For years people collected He dates that they couldn’t interpret, filed them away, and pretended they never existed. Then this paper came out and allowed the community to air its dirty laundry, admit that there were things about He dating we didn’t understand, and provide a comprehensive list of reasons your data might look odd.

Reiners, P.W., Thomson, S.N., McPhillips, D., Donelick, R.A., and Roering, J.J., 2007, Wildfire thermochronology and the fate and transport of apatite in hillslope and fluvial environments: Journal of Geophysical Research: Planets (1991–2012), v. 112, no. F4, do: 10.1029/2007JF000759. This is one of my favorite papers of the last decade, and one that I am consistently bringing up in discussions. I think it gets overlooked a little too much, maybe because it appeared in an Earth Surface journal or because its lead phrase is about wildfires, but this paper demonstrates one of the most important facts relevant to detrital He dating, that apatite fractionates over the land surface. Let me repeat that, apatite fractionates over the land surface.

Flowers, R.M., Ketcham, R.A., Shuster, D.L., and Farley, K.A., 2009, Apatite (U–Th)/He thermochronometry using a radiation damage accumulation and annealing model: Geochmica et Cosmochimica Acta, v. 73, no. 8, p. 2347–2365, doi: 10.1016/j.gca.2009.01.015. The recognition that radiation damage is the single biggest control on He diffusivity has revolutionized He dating, and made it a much more powerful technique. This paper, and another that was published at roughly the same time by Shuster et al., provide the fundamental models and explanations we now use to understand out He data.

Flowers, R.M., and Farley, K.A., 2012, Apatite 4He/3He and (U-Th)/He Evidence for an Ancient Grand Canyon: Science, v. 338, no. 6114, p. 1616–1619, doi: 10.1126/science.1229390. I have to include the only He paper that has made the New York Times Front page and caused more gruffing and questionable responses than any other in recent memory. In addition, it is a fantastic example of combining “traditional” and 4He/3He dating to address an outstanding geologic problem.

Guenthner, W.R., Reiners, P.W., Ketcham, R.A., Nasdala, L., and Giester, G., 2013, Helium diffusion in natural zircon: Radiation damage, anisotropy, and the interpretation of zircon (U-Th)/He thermochronology: American Journal of Science, v. 313, no. 3, p. 145–198, doi: 10.2475/03.2013.01. Once it was realized that He diffusivity in apatite is controlled largely by radiation damage, it stood to reason that the same would be true for zircon. This paper provides a boatload of data and presents a testable and usable model that has been used to explain natural data sets, and is now incorporated into most thermal models.

Things to Listen To Update

A while ago I posted about what I like to listen to when doing the inevitable important-but-dull tasks that occur all of the time in science. As an update, I’ll just link to a recent Slate article rounding up their list of the 25 best podcast episodes ever. Some are from my own favorite podcast list, but many are from podcasts I’ve never listened to. With a few weeks of mineral picking, lab cleaning, and dissolution work ahead, I have new things to listen to!

So here it is, Slate’s list of the 25 best podcast episodes of all time (as of now).

The Partial Retention Zone

One of the most important concepts in thermochronology is the Partial Retention Zone (PRZ for short, referred to as the Partial Annealing Zone in the fission-track world). The term PRZ is used to refer to a variety of things, all related to the realities of diffusion and radiogenic decay. I’ve often included descriptions of how the PRZ forms, and what it can tell you, in introductory thermochronology seminars, but I’ve never been totally happy with the results. At a recent meeting, it hit me that I should make an animation that shows a PRZ forming. Now, my animation skills are awful, but here it goes, the PRZ.

The simplest way to interpret thermochronology dates is via the concept of the Closure Temperature, a simplified notion that there is some crucial temperature above which the daughter product (let’s say He for the sake of awesomeness) immediately diffuses out of the system when produced by radioactive decay, and below which the daughter product is entirely retained. We all know that the concept of the closure temperature is a gross oversimplification, but it is handy when discussing the relative temperature sensitivity of different thermochronometers, and very useful for introducing the fundamentals of thermochronology. The problem though is that the concept of a closure temperature (as originally defined by Martin Dodson) is for a very specific circumstance, and cooling histories in nature are often much more complex. Instead of there being a well-defined temperature where diffusion goes from super fast to nothing, there is actually a broad range of temperatures over which the diffusively of the daughter product goes from very fast to very slow. As a crystal cools, it therefore moves through a range of He diffusivities. There are temperatures, for example, where ~15% of the He produced may be retained, or if the system is slightly cooled, 35%.

So imagine a chunk of crust with temperatures starting at ~0°C at the surface, and increasing downwards (for sake of argument, at a rate of 30°C/km). In this situation all of the rocks will start out with a (U-Th)/He date of 0 Ma (no accumulated He). What would happen to samples at different depths (or temperatures) over time? Simply stated, the rocks that are very cool near the surface would accumulate as much He as was being produced, so if you measured their date at different times it would correspond exactly to how long the sample has been sitting around. Samples from very deep positions (and very high temperatures), will never accumulated any of the He they are producing, it diffuses out immediately, so they will always have a date of 0 Ma. Samples in between? Well, that is where it gets complicated.

So here is my attempt at an animation. This shows the dates you’d measure for samples at different positions in the crust over a 40 Ma timespan. Check out of technology.

After 40 million years of radioactive decay and He production, only the samples in the shallow (cold) levels of the crust would yield a date of 40 Ma. Samples kept at moderate temperatures would have dates of something in-between, notably, not necessarily related to any geologic event.

Now imagine that this whole chunk of crust is uplifted and exposed, and you have the ability to take all of these samples and measure (U-Th)/He dates. This could happen, for example along a normal fault. A superb example of this was published by Stockli et al. in 2000  using data from the White Mountains in California.

Example of a cartoon chunk of crust exhumed along a normal fault. The dots represent samples from a variety of depths above, within, and below the partial retention (or annealing) zone. Figure from Stockli, D., Farley, K.A., and Dumitru, T., 2000, Calibration of the apatite (U-Th)/He thermochronometer on an exhumed fault block, White Mountains, California: Geology, v. 28, no. 11, p. 983.

Stockli et al. collected samples along the exposed footwall of a normal fault, calculated (U-Th)/He and apatite fission-track dates, and plotted them up against their reconstructed depth below the surface. The results will look familiar.

Figure showing AHe or AFT date versus depth for samples from the White Mountains. Note characteristic sigmoidal pattern developed in a partial retention zone. Figure from Stockli, D., Farley, K.A., and Dumitru, T., 2000, Calibration of the apatite (U-Th)/He thermochronometer on an exhumed fault block, White Mountains, California: Geology, v. 28, no. 11, p. 983.

Of course, when you have access to a big suite of samples like this, you can do a  lot of excellent geology. This is the reason that the Holy Grail for many thermochronologists is the age-elevation, or vertical profile. When you have samples from a range of elevations you can reconstruct the whole partial retention zone. You can even reconstruct paleodepths and paleo-geothermal gradients.

Truth is, even the shape of the PRZ can tell you a lot about a geologic history, as described by Wolf et al., (1998). Because different geologic histories will create different thermal histories, sample patters can yield first order information about the overall geologic story.

3 different thermal histories (solid line) showing the evolution of a (U-Th)/He date with time. Note that all 3 disparate thermal histories would all lead to the same He date because of changes in the retentivity of He with temperature. Figure after Wolf, R., Farley, K.A., and Kass, D., 1998, Modeling of the temperature sensitivity of the apatite (U-Th)/He thermochronometer: Chemical Geology, v. 148, no. 1-2, p. 105–114.

Modeled shape of the PRZ for the three thermal histories described above. Note that although the shallowest samples all yield the same date, the different thermal histories all produce drastically different PRZ shapes. Figure after Wolf, R., Farley, K.A., and Kass, D., 1998, Modeling of the temperature sensitivity of the apatite (U-Th)/He thermochronometer: Chemical Geology, v. 148, no. 1-2, p. 105–114.

So if you can sample an entire PRZ, you are well on your way to figuring it all out. The trick though is what to do when you don’t have this big suite of samples.

What I mean is that we often describe the PRZ as I have above, by discussing what a whole suite of samples will look like, and how you can use the patterns to do all kinds of excellent geologizing. What the PRZ also does though, is illustrate why low temperature thermochronometer dates can be exceedingly difficult to interpret. Look at any paper that has a geologic interpretation based on an exhumed and characterized PRZ. Now imagine that all you had to work on was one sample from the middle. In the example from the White Mountains, imagine that you only had one sample from ~3 km paleodepth with a (U-Th)/He date of ~40 Ma. What would be your interpretation? Would that date actually constrain any specific event?

In thermochronology we are always looking for ways to constrain our data. Age-elevation transects are one of them, but there are many others (multiple chronometers, RDAAM, large sample arrays, etc). Understanding the PRZ, and questions where in the PRZ your particular samples come from, is a huge first step.

 

 

The Hot Hand, Freakonomics, Climate Denial, and Closure Temperatures – Assumptions in Models

I started listening to a few sports podcasts rather religiously about 3 years ago. I self select for shows, avoiding anything that involves someone with a nickname or who yells all the time, basically avoiding anything that takes sports too seriously. My favorite, as I’ve mentioned in an earlier post, is Slate’s Hang Up and Listen, a shining star in the otherwise unimpressive Slate universe </rant>. One of the things that has really struck me while listening is the importance of “advanced statistics” to modern sports. These aren’t things that casual or stat-uninterested fans like myself care much about or can even define (like PECOTA, which is obviously an acronym for Player Empirical Comparison and Optimization Test Algorithm, duh), but include a huge assortment of metrics and statistical analyses that are designed to reduce the value of a player or strategy down to something that can be ranked and quantified, or to help evaluate what “common knowledge” is just not true. Some of these things seem reasonable, especially the emphasis on the absurdity of some of the more traditional stats and how they don’t really reflect the worth or accomplishments of a player, or how dumb some ideas are, like punting from your own half of the field. What strikes me though is the pretense that somehow these measurements and analyses are free of subjectivity, that they somehow elevate sports discussion to some objective plain far above the knuckle dragging fans and coaches who rely on their gut feelings. Emblematic of this movement for me is the Hot Hand Fallacy, an idea that has been around for a while, but recently became the poster child for how dumb casual fans are. The basic idea is that some people believe a certain player can develop hot streaks, where they are shooting a basketball, for example, statistically better than expected. According to a variety of analyses that look at the chances of making a basket as a function of if you either made or missed the previous shot, there was no such thing as a hot hand. Players basically have the same shooting percentage, but the human love of identifying streaks and patterns imposes the idea of a hot hand on our brains when we see them make 4 or 5 in a row, even if that isn’t statistically significant. The hot hand fallacy popped up all of the time, people used it to complain about players and coaches taking too many shots, changing their game plans, blah blah. To sum up, if you believed in hot streaks in sports, you were probably an unsophisticated doofus who couldn’t do statistics.

But then this study came out. What these authors suggested is that when someone feels like they are on a hot streak, they start taking harder shots, which means they make them less often, because the shots are harder. If you control for that in a particular way, then the analysis does support that players will at times develop a hot hand, that they will in fact shoot at a statistically higher percentage than expected.

I’ll admit, when I first heard about the hot hand fallacy, I was also one of those people who, maybe because I am a snooty scientist, liked to think of how smart I was for knowing that hot hands were a myth. This was dumb on my part, because I didn’t question the assumptions and simplifications that went in to the statistical model.

I even had precedent. A few years earlier I’d read Freakonomics, the best-selling book that used economic/mathematical analyses to study a variety of phenomena, basically applying economics math to human behavior, crime statistics, and a bunch of other things. My feeling reading this book was that you could summarize each study in the following way:

You might think this one thing, but you aren’t smart, and economists know everything and will now show that you are wrongedy wrong wrong.

I don’t mind being told I am wrong, I don’t mind learning new things, and I like to think I have a very open mind (for example, I now admit that my wife was right and a fish spatula is the greatest kitchen utensil ever made). However, I am inherently suspect of statements that imply some sort of mathematical analysis is straightforward and objective, especially one that requires a host of simplifying assumptions. There isn’t an unambiguous way to leap observations across scales of human behavior, measurement, psychology, and history. To do that, you need to filter and simplify data and define rules of cause and effect. So any study that doesn’t explicitly discuss its assumptions and simplifications should be suspect. This goes beyond the normal issues of reporting science in the mainstream that blow conclusions out of proportion, and makes it sound as if there are objective methods for understanding the direct effects of actions and policies. The farther you get from an action the more the effects are predicted in a Rube-Goldberg fashion. Sometimes this works well, and there are obviously some things that matter more than others, but whenever someone says “research shows X,” and they can’t explain the assumptions and simplifications, or don’t at least acknowledge them, then we should be suspicious.

It isn’t that the people doing the work aren’t smart, but they can often fall prey to a belief that mastery of one subject means mastery of others. My complaints about Freakonomics might stem from my inherent distrust of economists. This is certainly at the core of a recent event involving Nate Silver and his blog FiveThirtyEight.com. Nate Silver is a statistician who became famous for correctly predicting the last presidential election, and used that as a platform to launch his website. The premise of the website isn’t bad, using statistics to analyze a bunch of different things. The problem was when the blog waded into phenomena well outside of its depth. Specifically climate change.

Michael Mann has detailed the multiple problems with Silver’s climate analysis in many places, but it can be summed up as a smart person believing that their background prepares them to understand everyone else’s specialty. We’d balk of course if Nate Silver announced that he was now using his expertise to perform open heart surgery, build bridges, or defuse a nuclear bomb, but when he contradicts the experts in something equally as complicated, climate modeling, somehow we are OK.

Of course a big part of becoming an expert in any field is learning how to understand the data, how to make appropriate simplifications and assumptions, and how to evaluate the quality of interpretations based on the quality of the data and the construction of the models and other interpretive framework. Most of the IPCC reports of course are highly detailed discussions of climate change minutia, just as most of the papers I read or review are discussion of these details. The IPCC of course discusses a variety of independent models, using their dispersion or agreement as evidence for their reliability. Like many climate change deniers, Silver falls into traps that are shockingly ignorant to those who study the field, but is somehow blinded by his own confidence into thinking he has found something people who’ve dedicated their lives to a field have overlooked. Silver, and other deniers, aren’t that different than the man portrayed in the This American Life story Sucker McSquared, where a smart guy decides that Einstein was wrong, even though he doesn’t understand the basic math required for physics.

So what does this have to do with thermochronology and closure temperatures you ask? As a field, thermochronology is used in two main ways. It is either interpreted in a rather straightforward way using simple graphs, or it is modeled using a variety of complicated algorithms. I first learned about the models at a 2005 short course, and specifically learned about how wrong some of the assumptions I made about how heat acts in the lithosphere, how it is advected especially, can lead to gross misinterpretations of low-temperature thermochronology data. The models that have come on the scene have largely helped address this problem, focusing on the shape and evolution of the subsurface thermal structure. As thermochronology has been used in less and less ideal settings, these lessons have become more and more important.

What has been become apparent though, is that these models, while fixing one set of assumptions, have required many other simplifications that can often be just as significant. Landscape evolution models, for example, must often be simplified from actual landscapes, just because of limitations in computing and the inherent complicated nature of nature; faults become planar, erosion becomes instantaneous, and disparate lithologies become particles that all behave the same. In the same way the concept of the closure temperature, or closure depth, of a mineral is often simplified. For example, we know now that the diffusivity of He in apatite and zircon, and likely every other phase, is a function of radiation damage, which is itself a function of both U and Th content as well as the thermal history of the grain. More importantly, each of these things, closure temperature and date, come with associated uncertainties. In many cases, the uncertainties in the diffusion kinetics themselves are significant enough to affect models, yet there are as yet no good ways to assess the uncertainties in these models. In my reading and reviewing at least, I have yet to see “predicted dates” associated with realistic uncertainties.

My point isn’t that models aren’t useful, on the contrary, I find them insightful and very interesting. When used properly they can add a great deal to a study, and help you design your field time and sampling strategy to maximize your time and effort. My point is that with all of these things, it is absolutely crucial to understand the inherent assumptions and simplifications of any model or method that you use, and that just because you are smart and have mastered a technique doesn’t mean that you can honestly evaluate the world. I am sure these things will come, but IMHO assessing uncertainties in any interpretation, including the assumptions and simplifications used to construct the interpretive framework, whether it be a simple graph or a complex algorithm, is absolutely essential. For many of us, the details of these models are out of our depth, like Nate Silver wading into climate dynamics, but that doesn’t mean we can’t be aware.