Wednesday, November 26, 2008

My research history, in time and P-T

I like Chris Rowan's idea of placing his research on a geologic time scale, so I stole his image and edited it:

Since I did some geochronology (actually, a major part of my PhD was explaining that it was impossible for my data to be meaningful), I felt like I should include the bad data as well as my preferred ages for events.

But the time scale doesn't have enough dimensions for my research, so here's version in pressure-temperature space.

All the green is actual data from Vermont. The blue arrow is supposed to represent my PhD work, except that the rocks were really lousy for finding any kind of data, and I didn't work on the low-pressure ones that told a better story. The red is Colorado, both my senior thesis and current work with senior thesis students. The yellow is one rock deformation experiment that a couple of my undergrad students in Vermont did one summer. And I figured if I was going to include the really low-pressure stuff, I ought to include the water quality stuff I've advised, but it doesn't really fit on the diagram.

Monday, November 24, 2008

Ophiolites and ocean crust: slow tectonic shifts in textbook science

For more than fifteen years, I've been making my Plate Tectonics students read Assembling California by John McPhee. In part, I'm just using my dastardly professorial powers to inflict one of my favorite writers on helpless students. In part, I just want students to read lines like "You need a new geologist. You need a Californian." But mostly, I want students to think about ophiolites and the ways that scientists change their minds.

All of the textbooks that I've used simplify the ophiolite sequence in the same basic way. It's oceanic crust, stranded on land where we can see it and touch it and measure its structures and sample its minerals. Sediments, pillow lavas, sheeted dikes, massive gabbro, layered gabbro, layered peridotite, deformed mantle rock. The field geologist's answer to the layers recognized by seismologists on the ocean floor. The record of sea-floor spreading, one of the many pieces that fell into place as plate tectonic theory came about.

Getting that ocean floor onto continents where geologists can study it without submersibles or seismic waves is tricky. I remember arguing about California's Coast Range Ophiolite with my officemates (probably at Friday Beer after the high-pressure-metamorphism seminar). It's inland of the old subduction complex of the Franciscan Formation, so did that mean that it represented the closure of an old ocean basin? Or was it shoved up onto the continent as some kind of flake? Or, well, how do you do that mechanically, anyways? (Big picture tectonic arm-waving works better after beer. Increase pore fluid pressure and all that.)

Sometime in those nineteen years during since that seminar, the consensus understanding of ophiolites has changed. It hasn't been something that makes headlines, but in study after study, it's turned out that the trace element geochemistry has the wrong fingerprints for the ocean floor. Most ophiolites - even the famous ones like Troodos on Cyprus or the Semail ophiolite in Oman - most ophiolites formed above subduction zones.

I had heard rumors about this from igneous geochemists before, but an article in last month's GSA Today went further. If the geochemistry says that ophiolites aren't rocks that formed at mid-ocean ridges, well, we really shouldn't be using them to study what happens at mid-ocean ridges. We can't even use the sheeted dike complexes - sheets of cooled magma that intruded one another so that only half of any original dike is left - to talk about sea-floor spreading. At mid-ocean ridges, the rates of magma production and spreading are tied together, but above subduction zones, they're the result of two different processes. It's possible for the plate above a subduction zone to spread, if the downgoing plate sinks faster than the over-riding plate slide across it. (That's happening, for instance, near the Mariana Trench. And it's one of those complicating bits of tectonics that doesn't match the stories that get told in introductory classes, and that can serve as a GOTCHA! for partly-informed skeptics. But we know about trench rollback, and it's been incorporated into geologists' understanding of tectonics for a couple decades, even if we don't explain it that well to students.) The spreading of the over-riding plate might look like a mid-ocean ridge in the rock record - it's all extensional tectonics, after all - but the relationship to magmatism is different. Not the same relationship, not the same process. Still interesting... but not a way to study the way that oceans grow. Sorry.

So touching an ophiolite isn't touching a bit of old ocean floor, after all. And we don't need to argue about how the rocks got on top of the subduction complex if they usually are formed there. And a lot of tectonic arm-waving was for naught.

And the textbook science changes.


Robinson, P.T., Malpas, J., Dilek, Y., and Zhou, M., 2008, The significance of sheeted dike complexes in ophiolites: GSA Today, v. 18,. p. 4-10. (Available for free online here.)

Thursday, November 20, 2008

Random demographic graphics

I've just installed Office 2008 on my Mac in the hopes that it would make it easier for me to read files that people send me from PCs at work. So far, I've discovered that the Mac and PC interfaces are not at all the same, which explains why my students have been so frustrated when they've tried to do assignments on their home computers.

I'm going to get familiar with Excel by graphing the demographic data from the closed survey on my sidebar. Warning: includes default color schemes and gratuitous 3D pie charts.

Two-thirds of my readers are younger than me. That doesn't surprise me, but it means that I can't make Usenet jokes and expect people to get them. It also may explain this:

Well, not exactly. It looks like the quadrant compass is going the way of Usenet and geosynclinal theory. We're gradually replacing our quadrant compasses as they break... but I'm still going to make all my students convert all their measurements back and forth, because I'm a Big Meanie.

(Also, doesn't that graph look like it ought to have "One ring to rule them all..." inscribed on it?)

The next two graphs should have an axis labeled "number of responses" - I thought the total number of each of these was more interesting than the percent.

I'm not sure if "employment" is the right title for this graph. (I'm also not sure how many of the grad students also described themselves as employed in academia.)

Edit - By the way, "pre-college" is short for "pre-college educator" here. I was curious how many people were K-12 (or earlier) teachers, especially because Earth Science isn't taught in high school in many states (including Texas and California).

And finally, I have no idea why this bar graph insists on putting "other background" on top of "geoscientist." Perhaps it knows that geoscientists are down to earth, or something lame like that.

I know that this pair of questions left out some possibilities. (People who became geoscientists after a background in something else; people who majored in geology but got a job doing something different.)

And now I can delete those surveys from the side of this blog.

Wednesday, November 19, 2008

Field nightmare

I dreamed about teaching field camp last night.

I've taught field camp in several places, but one of my favorites is near Hoback Junction, Wyoming. We camp in this Forest Service campground with views of the Wind Rivers and a hot spring just up the road. The road up to it was in bad shape last time I stayed there, but it's still a gorgeous spot.

The problem with the campground, at least the last time I stayed there, was that you can't make reservations ahead of time, and there's no group site, so it's possible that we won't find a good spot for all the students to camp near one another.

And that's how my dream started. We got to the campground fairly late, only to find that three-quarters of it was closed off with deep piles of snow still on the ground, and all the remaining sites already filled. We drove around looking for a spot, and ended up trying to turn around somewhere down at the end of one of the campground loops.

And that's where we met the RV. It wasn't just any old RV. It was... well, it was immense. Bigger than an 18-wheeler. Tougher than a tank. And driven by someone who didn't look where he or she was going.

The RV was headed straight for my Subaru*. And it didn't stop.

In the end, my Subaru was crunched to half its original length. (I woke up before considering the possible analogy between shortened Subarus and regional strain analysis of collisional tectonic belts.)

So: academic nightmares by geology professors. (At least I didn't dream that I showed up for field work a day late, with no clothes, and sat on a cactus.)

*Don't ask me why I was driving my Subaru at field camp. Normally I drive a 15 10-passenger van loaded with students and gear. And, yes, I have a complicated history with vans, which many people can tell stories about. But there wasn't a van in this dream.

Monday, November 17, 2008

Geology and science fiction: what do I think?

I'm finally mostly caught up on work, so I can answer Peggy's questions about science and science fiction.

Questions for Science Bloggers

* What is your relationship to science fiction? Do you read it? Watch it? What/who do you like and why?

Yes, I read and watch science fiction. I've enjoyed it since I was a kid, probably because I found other worlds interesting. (Especially in comparison to the sort of petty interpersonal politics that dominated grade school, junior high, and high school.) I was fascinated by big and different.

As an adult, I like stories that imagine societies different from ours. Science fiction (and also fantasy) seem like great ways to explore human-ness by imagining what happens if things were a little different. Maybe the difference is some kind of technology. Maybe the difference is a cultural attitude. In a way, it's like experiments in science.

* What do you see as science fiction's role in promoting science, if any? Can it do more than make people excited about science? Can it harm the cause of science?

I don't think science fiction is particularly good at promoting science. (One word: Frankenstein.) An awful lot of science fiction seems to reveal a fear of the unknown, a fear of tampering with nature or with going too far in trying to understand something. It's not true of all science fiction (or fantasy), but I've seen it in places as different as Tolkien and the new Dr. Who.

Whether it harms the cause of science... well, honestly, I don't think that science should be a cause, really. Science is a sort of organized curiosity about the natural world, and it's sad to live amongst people who are uncurious and afraid of learning new things. But the introspection can be a good thing, as long as it doesn't become some kind of trite repetition of the story of the Tree of Knowledge.

* Have you used science fiction as a starting point to talk about science? Is it easier to talk about people doing it right or getting it wrong?

Geology is rarely explicitly part of science fiction. (Any time a different world is imagined, geology could be used to build a world that makes sense. I've rarely seen an imaginary world that makes geologic sense, unfortunately.) Off the top of my head, I can think of only one set of books that does geology well (Red Mars, Green Mars, and Blue Mars by Kim Stanley Robinson), and I have yet to run across a student who is familiar with them.

As for movies: I guess The Core could count as a science fiction movie (as well as a bad disaster movie). I've encouraged students to watch it and criticize the geology, but it's so goofy that it's difficult to get much science from it. I haven't seen the new Journey to the Center of the Earth, but I've watched the old version with geology students. Again, it was fun to laugh at it, but it was so wrong that it was hard to know where to start with a critique. And I mention The Day After Tomorrow in class to try to explain why the textbook talks about deep ocean currents in the context of climate, but mostly we end up laughing about Jake Gyllenhaal running away from wolves in New York rather than critiquing the science in detail.

* Are there any specific science or science fiction blogs you would recommend to interested readers or writers?

Anyone who wants to read more about geology should just subscribe to Chris Rowan's geoblogosphere feed, and choose their favorite blogs for themselves.

Friday, November 14, 2008

Geology, fiction, and science fiction

A post of links, because I'm trying to get some intro exams graded:

Magma cum laude has a great post discussing the portrayals of volcanoes in several books. And Biology in Science Fiction and Almost Diamonds are asking scientists and science fiction writers some questions in preparation for a panel at the ScienceOnline 09 conference. I think the discussions could be linked, easily.

Meanwhile, Erik Klemetti reminds us that real volcanoes can be as dramatic and tragic as fiction in his remembrance of the 23rd anniversary of the destruction of Armero, Colombia. And for science fiction writers who want to put a good subduction zone into their books, Brian Romans has a detailed three-part debunking of subduction denialists, which has led to a call for posts about geologic pseudoscience.

Wednesday, November 12, 2008

A not-quite-geology haiku

There's geology haiku meme going around. I'm doing lab work today. Or, well, trying. This isn't very haiku-like, but it reflects my day:

Time for some data -
the spectrometer is warm
but the shear gas won't flow.

Tuesday, November 11, 2008


Tonight's bedtime story was Where the Wild Things Are. My five-year-old is beginning to read words, so he wanted me to show him the words on the cover.

They're all in capital letters:


"That's shouting," my son said.

"Huh?" I said. I mean, there was some shouting earlier (thus the book), but we hadn't been shouting right then.

"The letters. That means shouting."

"Did your dad tell you that, or did you learn it at school?"

"My teacher told me. All capital letters means shouting."

They're teaching netiquette in kindergarten. (Maybe he'll learn not to feed the trolls, too. Either that, or they will start making LOLcats in art class.)

Monday, November 10, 2008

Wait! Field season isn't done yet!

Well, actually, I guess it probably is for this year:

(image deleted, because I screwed up my saving and linking)

There are two inches of snow on the ground. (I would take a picture, but I still don't have a camera.) Total daytime accumulation of 1-3 inches is expected, according to the National Weather Service. More snow possible tonight and tomorrow morning, and a mixture of rain and snow tomorrow afternoon.


Except my mapping class is still mapping. And some of them didn't start the most recent map, because they were voting last week.

The high temperatures are supposed to be above freezing today and tomorrow, so maybe it will all melt down here. Or maybe I'll need to go into the field next week, and talk about the cross-sections and the report this week (before some people have done their mapping).

I would make jokes about global warming going away, but someone would probably take them seriously. (Snow in late October or early November isn't that unusual here at 7000 feet.)

Sunday, November 9, 2008

Thinking through carbon sequestration

I've been trying to figure out what to say to my classes about carbon sequestration. As Brian mentioned in a comment, if we're going to lock carbon dioxide in rocks (well, artifically*), geologists are going to need to be involved.

I ought to be able to think through the problem from first principles. Carbon dioxide is part of all sorts of natural systems, after all. When it dissolves in water, it makes the weak acid that is responsible for much of the natural weathering of silicate minerals. It's released by metamorphic reactions, and the relative amounts of carbon dioxide and water in metamorphic fluids is important in determining which minerals are stable. It's one of several gasses that dissolve in magmas, and is important in its own ultra-weird magmas: carbonatites, which erupt molten baking soda in the East African Rift (and which concentrate rare earth elements in old deposits). At low temperatures, carbon dioxide, carbonic acid, bicarbonate, and carbonate ions make a fascinating buffer system. (I don't think I explained that one very well, the one time I taught environmental geochemistry. But it's still a fascinating system.)

And that's just the chemistry. There are also questions about fluid flow through rocks and fractures, and about possible rock fracture associated with high fluid pressures. It's hard to know exactly where to start, especially because the info sources that I've read don't try to explain things from first principles.

So how, exactly, is this carbon sequestration supposed to work, and how does it relate to all the various CO2 factoids that I've accumulated over time?

The answer depends on the rock and fluid involved, it seems. A number of possible environments have been proposed, and the issues are somewhat different for each one.

1) Use waste CO2 to enhance recovery of oil and gas. I was vaguely aware that carbon dioxide was used to help recover more oil from old oil fields (mostly because CO2 is produced near Durango - it's actually a commercially produced commodity). I didn't know much about how it works, though - was it used to increase the fluid pressure in the rock, and force the oil out, or did the CO2 dissolve in the oil and change its properties? It turns out that both happen. Yes, the carbon dioxide changes the fluid pressure. But it also dissolves in the oil and makes it flow more easily, which makes it possible to recover more of the oil.

This is already being done - in fact, carbon dioxide is produced commercially to be used in oil fields. So it makes sense to capture waste CO2 and use it instead. (Perhaps this should be considered CO2 recycling rather than sequestration, however - I assume that CO2 dissolved in the oil comes back to the surface with the oil. Not that there's anything wrong with recycling - make less waste, use if for useful purposes instead. But it doesn't take the CO2 away forever.)

2) Pump the CO2 into coal. The methane that adsorbs onto the surfaces of coal has become a commercially important source of natural gas (especially in the San Juan Basin, just south of Durango). Traditionally, the methane is released by pumping water out of the coal. But carbon dioxide also adsorbs onto the surfaces of coal. Maybe CO2 could be used to enhance coal-bed methane production, too.

This technique is being tried in my backyard. If it works, it's got a lot of potential, because coal-bed methane and coal-burning power plants (as a source of carbon dioxide) can be very near one another. (In fact, there are currently two coal-fired power plants near Farmington, New Mexico.) I don't know much about the surface chemistry of coal, so I don't have a good sense of what factors could make this work or not.

3) Pump the CO2 into deep, salty formation water. This is the target of the experiment that Lee Allison described today. I'm not entirely certain of the characteristics of the ideal "saline formation" sequestration project. I think the idea is that a) the salty water is isolated from useable groundwater, probably by some kind of low-permeability cap (like a classic oil reservoir would have); and b) the salty water would make a good chemical buffer for the carbonic acid. I'm not sure of the chemistry of the buffering - this is where I wish that I remembered the complications that happen in the systems of carbonic acid, bicarbonate, and carbonate when there's something in the system other than calcite and carbon dioxide. (I'm guessing that the high concentration of dissolved solids helps buffer the system, since the focus isn't entirely on limestones.) I'm also not sure how the dissolution of carbon dioxide in water affects the potential for problems with increased pore fluid pressure. (Increasing the amount of fluid in rock can make rock break. If you want to get oil out of the rock, this is a good thing; if you want to keep carbon dioxide from escaping, I'm guessing that it would be bad. Unless you can make the reservoir rock more permeable without breaking the less permeable cap?)

And this doesn't include ideas about using carbon dioxide to speed the weathering of silicates. (I think that's partly what's going on with the suggestions to sequester carbon dioxide in basalt, for instance.)

So I'm not sure how to discuss the issue in intro classes. I think I need more information. I would like to tell them about the ideas that have been proposed, however - particularly because some are happening in our own backyard.

*Carbon is naturally locked in rocks like coal, oil shale, and limestones. We let it out when we burn oil, coal, or natural gas, or when we make cement. But natural processes don't remove carbon as fast as we burn it for energy. So if we want to use fossil carbon for energy, and we don't want to deal with the consequences of putting all that carbon dioxide in the atmosphere, we've got to do something to speed up the process.

Saturday, November 8, 2008

Geoblogger meet-up at AGU?

Lee Allison asked if there is going to be a geoblogger meet-up at AGU. I know that Christie and Brian are going to be there, and I think Ron is organizing a session and Julian submitted an abstract. And Andrew is local to the Bay Area. (There are also some pseudonymous bloggers who have mentioned being there. I'm not leaving you out on purpose - I'm just letting you choose what info you want the world to know.) I'm sure I'm leaving other people out, too.

I'm arriving Tuesday afternoon and leaving Thursday afternoon (and I really want to catch up with some of my former students!), so I don't have a lot of flexibility. But would anyone be interested in meeting for dinner on Wednesday night?

Teaching intro geoscience workshop at AGU

Earlier this week, I received this message from Anne Egger, who is co-organizing two sessions and a workshop at AGU in December. I'm going to be speaking in the second session (and I'm looking forward to the poster session as well - the posters look interesting, and I like poster sessions for pedagogy discussions), but I'm not going to be at the meeting in time for the workshop. I found this summer's workshop very useful, though, and I expect that the one-day version will also be great.

Teaching Introductory Geoscience in the 21st Century

As part of the Cutting Edge program, we are offering a 1-day workshop on teaching introductory geoscience on Sunday , December 14 , in San Francisco, the day before the AGU Fall meeting begins.Many faculty have introductory courses in their teaching repertoires, and those courses span a wide range of subject areas, including physical and historical geology, environmental science, oceanography, natural hazards, and courses that follow a regional or topical theme. This workshop will bring together faculty from a wide variety of institutional settings and backgrounds with the common goal of sharing ideas about improving the pedagogy and content of all of our introductory geoscience courses. The 1-day workshop both builds on and serves to disseminate the results of an identically-titled workshop that took place July 14-17, 2008.

Conveners: Cathy Manduca and Anne Egger

DEADLINE TO REGISTER: Friday, November 21
NOTE: You do not need to be registered for the AGU meeting to attend this workshop.

More information about the workshop can be found here:

To register, go here:

Goals and Format
During this 1-day workshop, we will explore the following topics

• How can we maximize the long-term impact of our introductory courses?
• How do we engage students in the real process of science even at the introductory level?
• What are some approaches to designing a new course or breathing new life into an existing course?
• How can we make activities we currently use in our courses more effective?
• How do we approach challenges like teaching large courses, courses with no lab component, or courses in urban settings with nary an outcrop in sight?

The workshop format will include plenary talks, large and small group discussions, and time for planning changes to your own course and activities. In addition, all participants will contribute to development of the online collection of introductory teaching activities for the classroom, lab or field. In doing so, workshop attendees will consider what makes effective activities and assignments and will review and make suggestions for improving submitted materials.

Thursday, November 6, 2008

Demography, geoscience jobs, and crystal-ball gazing

When I got the latest Geoscience Currents from AGI, I immediately printed it out and hung it on the wall in the geology majors' study room.

Here's why:

AGI collected information from a variety of groups that keep track of various employed geoscientists and graphed their membership by age. (They don't have information from any mining industry groups; SEG in this case is the Society of Exploration Geophysicists, not the Society of Economic Geologists.) Hydrologists are the only group that has significant numbers of 40-something geoscientists; my generation was not hired to work for the oil & gas industry.

I hung up the page because of this line from it: The majority of geoscientists in the workforce are within 15 years of retirement age. But after I hung it up, I wondered about the assumptions being made about future employment opportunities.

When I was a senior in college, I had The Conversation with my academic advisor: "What do you want to be when you grow up?" He suggested that I go to graduate school. His generation had been hired to educate the Baby Boomers, he said, and his generation was going to retire soon. There would be lots of academic jobs to replace people like him. If I went to grad school then, in 1989, I would get done just in time.

I did go straight to grad school, though I would have taken a job if I had found one. But when I graduated, jobs were hard to come by. I know a lot of talented geology grad students who left the field after their post-docs went nowhere. My advisor's generation did retire, yes, but there were many more grad students than there were retirements. And there weren't many jobs in industry, and the USGS wasn't hiring, and academic departments were being closed.

The situation for industry jobs now may be different. There are far fewer undergrad geology majors than there were in the early 1980's. The supply of young geologists may very well be lower than the demand.

But it's a matter of supply and demand, not of needing to replace the exact number of geologists who are about to retire. How many geologists will the oil & gas industry need for the next thirty years? What if oil production has peaked? What if concerns about global climate change combined with high oil prices drives a shift to different energy sources? How many geologists will oil & gas need during busts? How many will the mining industry need? (And what will they be mining?) My Magic Garnet Ball isn't clear enough to tell. (Stupid inclusions.)

I know that "the market" is taking a beating right now, but I still look to it for signals that industry really needs geologists. Are people being hired with bachelor's degrees? What are they making for salaries? Are companies offering to pay students to go to grad school, or do they expect students to prepare themselves for a job that may or may not be there in two or three years? Are PhDs with some industry experience getting new jobs when they are laid off (and how long does it take to find a new job)?

I've adjusted the things I cover in structural geology to try to fit the needs of students who might work in groundwater, in oil, or in mining. I want my students to be ready to take jobs if they are available. But I wonder whether we are being honest about the future. I can't predict the stock market... and geology jobs are as much at the mercy of economics as other jobs are.

Edit: Andrew at discussed a related article in GSA Today here. (The GSA Today article discusses the age distribution of GSA member, and has as a take-home message that my generation of geologists needs to take over leadership roles in geoscience organizations. The Structure/Tectonics Division of GSA has had multiple volunteers for leadership positions from my generation in the past two years, at least. My generation of academics is barely post-tenure, though, despite being old-school already. We're not used to people taking us seriously.)