Follow Up to the Last Post

I was reading my most recent EOS and came across this Forum article, written by Professor Seth Stein, a geologist at Northwestern University. You have to be an AGU member to access the online version, but in it he discusses the importance of selling earth science. I usually dislike references to academics or science using marketing terms, but I found his argument very compelling.

The "CSI Effect"

In a slightly related post, the New York Times has an interesting article this morning about a man who was wrongly convicted of "stabbing, beating, biting and strangling a social worker in upstate New York." The case revolved largely around bite mark evidence, with a local dentist acting as an expert witness, testifying that the teeth marks on the victim matched the accused perfectly. DNA evidence has overturned many cases (as it did with this one), so that isn't really new. What interests me about this story though is what it says about the perceptions of science in society. Even though most people do not make a living using science, it has real world consequences

Lawyers, for their part, are taking steps to counter what they call the “C.S.I. effect,” when juries become overly impressed by forensic evidence. During jury selection, it is not uncommon for them to ask potential jurors about their television-watching preferences to weed out those who seem unable to separate fact from fiction.

Mrs. Dip-with-a-different-last-name pointed this article out to me last week, which I think is similar in theme. What I really find interesting about this is not that his research is controversial, but how quickly a bastardized version of his research was spread throughout the blogosphere and traditional media. In both of these cases, incorrect versions of science led to serious misunderstandings.

I tend to blame us scientists for this gulf in public understanding. True, most people could spend more time understanding the basics of the world they live in, but that is easy for us to say, it is how we make a living. I get to spend all day thinking about science, and expecting people to become experts would be like expecting me to become an expert in anything else, auto maintenance, plumbing, baking, computer programming....If I instead think of science as something I'd have to learn about after a long day of work, like any of my other hobbies or any other important aspect of life, it seems daunting. This is one of the reasons I think that science blogs can be important, I think we as a community need to become better about getting our messages across. Political junkies have really excelled at using the internet, and blogs in particular, for this purpose. Who knows, perhaps it wouldn't be so easy to cut earth science programs, or to cut funding to the USGS if we were better at getting our messages across? As I mentioned in my first post, we must make a connection between science and everyday life.

This is why public outreach is so important. There are many simple things we can do.

1. Let's support high school teachers and students. After all, this is where most people get the majority of their exposure to science, and their high school science courses will largely determine how they approach science for the rest of their lives. Supporting high school science can be as simple as visiting classrooms, judging science fairs, tutoring, etc., or as involved as providing research experience to students over the summer (one professor in my graduate department was especially good at this). As even easier way is to support the friends and colleagues of ours who decide to teach high school science. It seems a rather thankless task, very hard work that I don't think gets enough respect from the professional science community.

2. Let's support undergraduate survey courses and the people that teach them. Same reasons as above, that is the only chance to introduce earth science to most people. These are future voters, politicians, jurors, etc., we can't waste those chances.

3. Be a salesperson. I don't know how Physicists do it, they must be the best sales people in the world. Somehow they can convince governments to spend tens of billions of dollars on such boondoggles as particle colliders. Seriously, this astounds me. Not that I don't find the science interesting, in a perfect world with unlimited resources I would say go for it. But we all know that competition for funding is tight, yet somehow these projects get funded. Earth Science is very relevant (well, maybe not thermochronology, but you get my point), and we need to sell it that way.

4. Let's all refrain from blaming the public every time science is misused. At least in my opinion, the shortcoming is mainly ours. We are fortunate to be able to spend our lives doing jobs that interest us, and the extra effort it would take to share some of that knowledge really isn't that much.

5. We need to find a Carl Sagan of geology, someone who can take the message to the public. And, when we find him or her, we need to not disparage their work (as happened to Carl Sagan, and to many academics who try to become popular).

There will be more rules, I am sure.

Apparent Dip Music Club #5 - Townes Van Zandt

This song became famous thanks to a cover by Willie Nelson and Merle Haggard, but I think the original Townes version, or the one found on this amazing posthumously released album, really capture the sadness of the song. Townes is one of those artists I never knew I liked until long after he had died. Like Stevie Ray Vaughan, his death came a t a time when he had turned his life around. Those of you interested, I highly recommend the documentary Be Here to Love Me, it chronicles Townes's life and music, complete with live performances and interviews.

Labs on TV

One of my [many] pet peeves is the portrayal of science labs on television. It turns out that there are some universal rules that TV follows in the construction of a lab. For a variety of reasons I can't stand these shows, but I do get a kick out of some of the things I've noticed, especially labs on "hip" shows.

Rule #1. All labs must have brightly colored liquids, especially red and blue ones, preferrably kept in a backlit cabinet or shelf.

This rule is illustrated in the above picture from one of the bajillion CSI series (not sure which one). Notice how few of the "chemicals" are clear, how few need to be labeled (calling Health Physics), how many aren't even capped! This rule transcends different television shows, all labs must have multicolored liquids prominently displayed, that means science. Either that Kool-Aid plays a much larger role in other sciences that it does in geology. I can't count the number of times I've asked my assistant to "hand me that green liquid, you know, the one we keep unlabeled in the uncapped erlenmeyer flask from the backlit glass cabinet," must happen 30 times a day.

Rule #2. Labs must be poorly lit.
Again, let's place some spotlights on things in the background, but why bother to have overhead lighting? Kind of messes up the dramatics. I will buy that most real labs might not have windows, OK, but really, no one remembers to turn on the lights? My real belief is that this saves the set designers boatloads of time, all they need to do is turn a flashlight on a few test tubes or a microscope and boom, instant lab! To be fair, overhead fluorescent lights are probably bad for clear bottles of red liquid, they most likely need to be kept in the dark. Maybe my experiments will actually work better with mood lighting, don't knock it before you try it.

Rule #3. Blue background light means science.



The lighting goal of any lab on TV is to mimic that of an aquarium at night. Notice in all of these shots what an eerie bluish aqua lighting is in the background. Then again, to be fair, perhaps they are surrounded by aquariums.

Rule #4. To really look at things in your dark, bluish lab, you must use a light table.

As any geologist with a 35mm slide collection will tell you, light tables are very useful, they really do help when looking at transparent images. Why they help with actual photographs, I have no idea. Granted, this is some of the only light available, so perhaps they need to take what they can get. According to TV, light tables are the best way to view almost anything, pictures, physical evidence, perhaps even bottles of red "chemicals."

Rule #5. All scientists are young, fashionable, and very attractive. I won't argue with this one, because it is true, especially in the world of thermochronology.

I am sure there are more rules, but these are so far my big 5. Any ideas?

Attention Mississippi Voters

Just a brief note referring everyone, especially those of you who may live or vote in Mississippi of State House Bill 625, put forward by Rep. Mike Lott, which would require that if evolution is taught in public schools, then both creationism and intelligent design must be taught as well in order to provide the students with "a comprehensive eduction in science." I'll also cross post with another related geoblogospheric post from our good friends at ...Or Something, and provide a general like for those interested to the National Center for Science Education. Those of you who agree there needs to be a balance in science education are also directed to one of my favorite alternate theories.

(U-Th)/He Thermochronology

UPDATE : If you found this web page while looking for information on labs where you could do (U-Th)/He analyses, please check out the web page for the new He lab at the University of Colorado - Boulder.

In response to a comment I received on an earlier post, I thought it might be a good idea to give a brief overview of (U-Th)/He thermochronology. Chances are I will have pleanty of posts in the future that will touch on the subject, so this could be useful.

Like all radiometric geochronometers, (U-Th)/He chronology is based on the radioactive decay of a naturally occurring parent nuclide (in this case, U and/or Th) to a stable daughter product (in this case He). We typically think of U and Th decaying to Pb, which it does, and this is the basis for another geochronometer. U and Th each decay by what is called "chain decay", meaning that there are many steps and many intermediate nuclides in the decay process, and decay from one of these to the next is accomplished via wither alpha or beta decay. ²³⁸U for instance, has 8 alpha decay steps in its decay chain. During alpha decay, an alpha particle (2 neutrons and 2 protons) is emitted from the nucleus. Alpha particles are He nucleii, as soon as they leave the nucleus they pick up some electrons and shabang, a He atom. ²³⁵U undergoes 7 alpha decays, and ²³²Th produces 6. Below is a schematic diagram of the decay chain for ²³⁸U, the more abundant U isotope. You can see that there are multiple paths the decaying atom can travel, and that it must experience some number of beta decays, along with exactly 8 alpha decays. Beta decays are when a neutron is converted into a proton and an electron, and that electron expelled from the nucleus (simplified, but you get the point), so during a beta decay, the number of neutrons in the nucleus goes down by 1, and the number of protons increase by 1 (the number of protons is what defines something as a single element, changing the number of neutrons just makes something an isotope of the same element).
²³⁵U and ²³²Th have similar decay chains. So, if you measure the amount of the daughter product (He), and the amount of the parents (²³⁸U, ²³⁵U, and ²³²Th), and know the rate at which decay occurs (which we know exceedingly well), then you can calculate the amount of time that the He has been accumulating.

But helium, really, helium in a rock? It seems like a stretch, especially considering our everyday experience with He. It makes up only about 1 ppm (part per million, or .0001%) of the air we breath, it is so light that it can escape our atmosphere. It escapes from balloons, canisters, everything. The idea then was that it must escape from rocks and minerals right away. This was what Strutt and most of the early workers I discussed in an earlier post believed. When they dissolved the minerals in acid of course, the He was released immediately. It turns out that certain minerals actually can retain He relatively well. Apatite and zircon, two common accessory minerals that typically contain 10's to 1000's of ppm of U and Th, can hold onto He for geologically meaningful lengths of time (millions of years), as long as the temperatures don't get too high. Below is an image of some apatite crystals from a granite in western Utah that I worked on, notice the scale bar. It is fairly easy to "date" an individual crystal, typically we measure 4 or 5 individual grains to make sure the ages are reproducible.

He diffuses rapidly out of apatite at temperatures greater than about 70°C (again, talking geologic time scales). Radioactive decay of course doesn't care about temperature (well, not anything close to a temperature found on or in earth), so it is occurring all of the time. At higher temperatures, the He that is being produced is diffusing out of the crystal and leaving the system, into the atmosphere. If you are not retaining any of your daughter atoms, you have a zero age. Once the rock cools, you start to retain the He, so the age you measure with (U-th)/He is not necessarily a formation age, but rather a cooling age, measuring the time since the rock cooled to the temperature at which it could retain He. There area actually many "thermochronometers" like this, systems that geologists use to determine the time-temperature history of a rock or geologic terrain.

Measuring the different nuclides is a little tricky. As far as I know, there is no one machine that can accurately and preceisely measure U, Th, and He. U and Th are often measured together (like using this amazing machine), but He is a different matter.

For a variety of reasons, we tend to measure He from single grains, I work primarily on apatite (Ca-phosphate, the same mineral that makes up our bones and teeth, it is also a common accessory mineral in granites and related rocks). The first step is to get the He that is trapped in the crystal out, so we can measure it. A common way to do this is to heat the crystal with a laser

These are pictures I took of the laser I used in grad school, an Ar-ion laser. Many different kinds of lasers can be used, the Ar-ion has the advantage that the light is in the visible spectrum, so you can take really amazing pictures of it. The He that is generated during the radioactive decay an that we de-gas from the crystal with a laser is ⁴He. To measure the total amount of ⁴He we spike it with a known amount of ³He, and measure the isotopic ratios on a Quadrupole Mass Spectrometer. There are a few intermediate steps, mainly designed to clean up the gas and remove any contaminants, that is where the cryogenic charcoal trap I showed in a previous post comes into play.

The lab that measures He cannot measure U and/or Th. So we then take the crystals, dissolve them in nitric acid (for apatite, nastier stuff for zircon), spike it with known amounts of ²³³U and ²²⁹Th (or some other appropriate isotope),





and measure the U and Th on a magnetic sector ICP-MS.



Once we know the amount of U, Th, and He, we can then calculate an age. All of the steps up until now are pretty straightforward, now of course comes the hard part, interpreting that age. Sometimes that is fairly obvious, sometimes it isn't.

There are many other aspects of this technique that I find interesting, and that are very important for anyone wishing to use it. For a technical discussion I'd direct you all to an excellent review paper written in 2002:

Farley, Kenneth A. (2002) (U-Th)/He dating; techniques, calibrations, and applications. Reviews in Mineralogy and Geochemistry, v. 47, pp. 819-843.

So, I hope this clears up a bit about the technique. I am sure posts in the future will explore the topic a little more, for example the issue of alpha-ejection, He diffusion, etc. If you are interested in geochronology, one additional place I'd recomment you check out is the Earthtime project. Cheers.

More dramatic evidence of climate change

Scientists are now predicting the bears from Illinois will be migrating to southern Florida in 2 weeks. This is either due to climate change, or to certain angry bears who were seen running all over the place this past Sunday.

Apparent Dip Music Club #4 - Stompin' Tom Connors

Today's music club offering might be new to those of you from south of the border. I first came across Stompin' Tom Connors, and this song, while I was in the field checking out what I thought would be my thesis field area (project never worked out, but that story is for another post; its a good one, I almost killed us). My office mate (we will call her Dr. Swartpuntia) and I had spent a great week and a half in southern British Columbia, near the beautiful town of Revelstoke, and were on our way back south listening to the CBC. They were announcing the results of this contest, where they had asked the listeners to call in with "the best trucking song ever written". Dr. Swartpuntia and I threw out our guesses, mainly "Truckin'" and a few others she knew of. The DJ came on and said, "while we received many good candidates, far and away the winner is Bud the Spud, by Stompin Tom Connors." What?!? This blew us away; as music snobs we both thought we would have at least heard of the song, if not already spent hours discussing the true meaning of the lyrics (hello "Tangled up in Blue" and "Last Trip to Tulsa"). Anyways, when we got back to school I was able to collect some Stompin' Tom, and now love a lot of his songs. This is perhaps his most famous, but please check out the rest of his catalog. Incidentally, I was also given a great gift related to this song, something that has a place of pride on my bookshelf. Youtube has some fantastic Stompin' Tom videos, mostly concert film, but one excellent video for Margo's Cargo that almost made me understand what the song was about (a cow-dung clock?).

ExxonMobil and Climate Change

I wanted to bring to attention this report published by the Union of Concerned Scientists, detailing the efforts of ExxonMobil to muddy the climate change debate, primarily through channeling funds into organizations trying to discredit a position held by the vast majority of the scientific community.

ExxonMobil has manufactured uncertainty about the human causes of global warming just as tobacco companies denied their product caused lung cancer," said Alden Meyer, the Union of Concerned Scientists' Director of Strategy & Policy. "A modest but effective investment has allowed the oil giant to fuel doubt about global warming to delay government action just as Big Tobacco did for over 40 years.

As with most everything put out by theUnion of Concerned Scientists, it comes with numerous appendices and an extensive reference list.

Apparent Dip Music Club #3 - Gillian Welch, David Rawlings, and the Old Crow Medicine Show

Here is music club offering #3, a bunch of people I like singing a song I like, a song that if I could play an instrument and/or sing I would totally cover, especially when I opened for more popular acts like Reach of Imagination.

More Urlacher Information

I realized that it might help my readers if I provided some useful values in the new format, the Ur.

Gas Constant = R = 8.314 X 10^-3 Ur mol^-1 deg^-1

Activation Energies commonly used by Noble Gas Thermochronologists
He in apatite = 138.1 Ur/mol
He in zircon = 169.0 Ur/mol
He in sphene = 186.6 Ur/mol
He in titanite = 186.6 Ur/mol (har har)
Ar in kspar = 183.3 Ur/mol
Ar in biotite = 197.1 Ur/mol
Ar in muscovite = 179.9 Ur/mol
Ar in hornblende = 276.1 Ur/mol

To help move us all into the new system, it is good to remember that 1 Ur = 1 kJ

I propose a new SI unit for energy

A while ago I had the chance to teach an introductory earth hazards course at a university near where I went to grad school. All in all it was a fantastic experience, and I learned many things while doing it. I found that one of the more important concepts needed to discuss many earth hazards is energy. Specifically, the amount of energy given off during different events, or the role of energy in producing events. The textbook we were using discussed energy in terms of an erg. Ergs are one of those units I really don't have much of a feel for, kind of like electron-volt and tesla, I can use them in equations, but I have no physical basis for comparison. I fear I am not alone in this, many scientists must often use units of measure they have no real sense for. So, today, I would like to propose a new unit of measure to augment the erg (or joule or whatever). The new, official Apparent Dip approved unit of energy is ........... the Urlacher. 1 Urlacher represents the amount of (kinetic) energy Brian Urlacher has when he is running at top speed and about to flatten some poor sap on an opposing team. For those of you still using the old system, 1 Urlacher (1 Ur), is equal to 10¹⁰ ergs.

So, for reference:

A 90 mph fastball has 0.1 Ur, or 10 cUr
A 1 megaton nuclear bomb releases 10¹¹ Ur, or 100 GUr
Mt. St. Helens released 10¹³ Ur, or 10 TUr
The largest earthquake in recorded history (1965 Chile) released 10¹⁶ Ur, or 10 PUr
And the world's nuclear arsenal is roughly 10¹⁷ Ur, or 100 PUr

(I am sorry about the original error in the math, pointed out by the Lab Lemming, I got carried away with the copy and paste of the html marks for superscripts, and committed a scientific sin, forgetting to check everything)

This announcement is of course partly in honor of todays victory by America's Team, the Chicago Bears over the Seattle Seahawks. This is the first playoff victory for the Bears since I was a freshman in college, and it was beautiful. In addition to Rex Grossman having an excellent game, punter and place holder extraordinairre Brad Maynard set up a rough snap in overtime for Robbie Gould to pound through the uprights. It was a 49-yard field goal but would have been good from 60. Brian Urlacher is of course the best defensive player in the NFL and one of the greatest linebackers to ever play the game. If the Ur is adopted, there are hundreds of NFL players who will know exactly what it feels like to get hit with that much energy. Go Bears.

Al Gore and Condoms

I'd like to direct you all to another geology blog called ...Or Something and a recent post that discusses the teaching of science in classrooms. Not only is it a good take on an interesting article, but it somehow gets the words "Al Gore" and "Condoms" into the same sentence.

Friday, January 12, 2007
The myth of the "opposing view"

"Condoms don't belong in school and neither does Al Gore."

I can't resist commenting on this article...even if no one reads it...and even though I should be working right now. Below are excerpts from the report (click on link above to see original) and then my snide remarks in this font.

Apparent Dip Music Club #2 - David Francey Again!

I decided to do another David Francey concert clip for a couple of reasons. First, I am really excited that I received a positive comment on the first post, from his wife no less! That made my week. Second though, the weather here in the snowy northeast has finally turned wintery and cold, and I have been listening to David Francey nonstop. It just seems to fit perfectly. In addition he is someone everyone should know about, and what better place to find out about good music than a geology blog. There, three good reasons, more than enough. Enjoy.

Enormous Earthquake

I woke up this morning to a boatload of emails from the USGS automated earthquake notification email service I subscribe to. They are all associated with an enormous earthquake that occurred east of the Kuril Islands at the boundary between the Pacific plate and the Okhotsk plate. The original magnitude was estimated at 7.7 but was later revised to 8.2. This is similar in size and not to far away from a magnitude 8.3 earthquake that struck the region back on November 15, 2006. This is of course much larger than the magnitude 6.9 Loma Prieta earthquake that rocked the San Francisco Bay area in 1989, and much smaller than the magnitude 9.1 Sumatran earthquake that spawned tsunamis that killed more the 250,000 people. Earthquake magnitudes are logarithmic and describe the size of the amplitude of waves on a seismogram. So, this recent quake in the Kuril Islands is roughly 20 times larger than the Loma Prieta earthquake. The amount of energy released during the earthquake is different, using a calculator supplied by the USGS I calculated that this recent quake released roughly 126 times more energy that Loma Prieta. According to the moment tensor solution it was a normal fault earthquake (see below).
It looks like the area is remote enough that there is no direct damage from the quake. Especially after the Sumatran quake the first concern of many is a tsunami. At least according to the Anchorage Daily News it looks like the tsunami warning has been lifted, which is of course good news.

From the shore of Lake Manly

These are images from what used to be the northern shore of Lake Manly, the Pleistocene lake that once occupied what is now Death Valley. Lake Manly was roughly 600 feet deep, and over 100 miles long. Pretty impressive. I took these pictures in the evening on a field trip, if you are ever in Death Valley, this is the time to see things in the main part of the park. Spend the afternoons in the mountains surrounding the valley, and save the central valley for beautiful and cool evenings like this. Like with all of my pictures, please contact me if you'd be interested in higher resolution copies.

Apparent Dip Music Club #1 - David Francey

Song 1 on my music club (shamelessly ripped off from the good people at crooks and liars), this is David Francey, a Canadian folk singer I ran into about a year ago. Only one of his albums is available in the US right now, but I fortunately have a Canadian geologist friend who supplied me with the rest. Now just to get him to tour in the states. If you listen to enough David Francey you definitely hear hints of Stan Rogers, more the spirit of Rogers, not some kind of rip off, because who could duplicate Stan, more the sensibility of Rogers. One hell of a lyricist.

Fitting line through Data #2

So here is the published version of the graph I posted previously, this time you can see the y-axis value and the line drawn through the data points. As I mentioned in my fist post on this topic, my biggest beef is that the uncertainties associated with the salinity measurements, or even the time measurements, are not included in the graph or mentioned in the article or figure caption. One can imagine that if the uncertainties associated with these measurements are large, maybe 1 or 2 ppt, then drawing any kind of curve, let alone one with so many precise dips and peaks, is very sketchy.

This will hopefully be a regular feature of this blog. As I mentioned, I left graduate school with a very heightened awareness of error propagation and a very critical eye for how data are presented. Just because something is published does not mean it is flawless.

It is entirely possible that the shape of this curve is based on other factors, perhaps other data sets, or more likely some known and predictable relationship between time and salinity that these data happen to agree with. If that is so, it was not mentioned in the text of the article.

Show your uncertainties!

Drawing lines through data, predetermined patterns, and good imaginations

One of the topics my PhD advisor was the most concerned about was user bias in presenting data. I spent a lot of time learning how to propagate errors through calculations, and how to decide what kind of curves are appropriate to fit to various 2D data sets. I came across an article in a recent publication (pub and author name withheld for now) that got me thinking. Above I have posted a modified figure from this publication, the x-axis is time, the y-axis is a value measured in sediment cores. Take a few minutes and decide how you would draw a line through this data if you needed to, I will come back with their version in a few days. I have erased everything but the data from this figure.

Correlating data with lines or curves can of course be informed by expected patterns, where one value has been shown to vary regularly with the second. I am not an expert in the branch of earth science discussed in this article, so perhaps I am missing something. That being said, enjoy.

One more note, my first beef is the lack of uncertainties associated with the data points. They should either be on the figure or there should have been a disclaimer in the figure caption mentioning that the uncertainties are smaller than the size of the symbol. You will have to take my word that it doesn't.

Political Interference in Science

The Union of Concerned Scientists has posted on their website their A to Z Guide to Political Interference in Science, not all of them are earth science related, but there are quite a few. It is quite staggering really, of course, few scientists think this problem has gotten better during the current administration. Many of these issues have persisted through democratic and republican administrations alike. That being said, it is obvious that science and/or credible evidence have played a very minor role in the Bush administrations decision making process. The UCS is a non-partisan group, and have been plenty critical of every politician who views scientific evidence and findings through political sunglasses, which is to say this is not some left-wing hack group looking for things to complain about.