I found yami's ice-bound volcanoes, and although she hasn't commented back yet, I'm going to post a new one before I go to bed.
I'll invoke the Schott rule again: previous winners, please wait one hour for each time you've won. (Ron's put together a master compilation if you can't remember how often you've won.)
Tell me where it is and tell me about the geology. (But if you've won before, wait an hour for each time you've won.)
I probably won't be online much tomorrow. (I'll be
working very hard on putting together a syllabus for my advanced structure class downloading and tagging all my field photos alternately playing "baby pterodactyl" with my four-year-old and reading the last Harry Potter book.) So if you find the location, please go ahead and post a new Where on (Google) Earth, so the usual suspects won't get twitchy.
Friday, July 20, 2007
I found yami's ice-bound volcanoes, and although she hasn't commented back yet, I'm going to post a new one before I go to bed.
Posted by Kim at 8:33 PM
I've spent part of the past week in the field with my thesis student, backpacking into the fringe of a nearby wilderness area and then scrambling up avalanche chutes to look for cool metamorphic minerals in Precambrian metasediments. It's hard to explain what we're doing in a sentence or two - when we meet backpackers or fishermen, we usually just say we're geologists, and they ask if we've found gold, and when they say no, they assume we failed. (But we found sillimanite, and andalusite, and garnet, and some really funky reaction textures, so we're happy metamorphic petrologists. When I download my photos, maybe I'll post some.)
We've cut a couple miles off our backpack (and found a good river crossing) by making friends with the property owner on the wilderness boundary. When we go through the gate, we try to keep the donkey from escaping, and when we drive past the house, we stop and say hi, and usually hear some entertaining stories in return.
This time, we went through the usual questions. Did we find gold? No, sorry, but we'll keep looking. (It's not that big of a stretch; there are gold mines in the county, and there is apparently some mineralization associated with the pluton whose aureole we're studying.) But this time they asked some more questions, and my student did a nice job of trying to explain metamorphism in a few sentences.
And then the property owner decided to make this a teachable moment for her guests, and started talking about how all this had been under the ocean, and then the dinosaurs came, and then God made the mountains so the dinosaurs would have something big to walk around on.
My student and I just kind of stammered and said, yeah, this was all a long time ago, and headed out. (In our defense, it was late, and we hadn't eaten supper, and I have a four-year-old whom I wanted to see before bedtime.) But I wonder: should we have said more? We're working in Precambrian metasediments, probably about 1.7 billion years old, a kilometer-thick pile of metaconglomerate that grades upward into lovely cross-bedded quartzite and finally into a little bit of pelite. The underlying rocks tell the story of the building of North America by accretion of island arcs; the conglomerates could have been deposited in some kind of syn-tectonic basin or another, maybe during collision of an arc, maybe during some kind of post-collision rifting, maybe in some kind of small basin along a releasing bend on a strike-slip fault - we don't know how they formed, but they are thick and spatially restricted, and that says "yo! mountains nearby!" to me. And then they've been metamorphosed in the aureole of an anorogenic (?) granite. And then, after another 900 million years or so, they ended up under the Paleozoic passive margin sediments of North America, and then the dinosaurs showed up (after another 300+ million years or so), and then the dinosaurs went extinct and the mountains formed (probably in that order). And, you know, the story is really cool, and the mountains are beautiful, and I'm a big fan of knowing the country where one lives, whether one is a geologist or not.
But we were essentially guests, of someone who was interested in finding ways for us to make use of her property, and we wanted to maintain good relations. And, well, where do you start? (And she could have been pulling our legs, or exaggerating. And for the deeply religious, God pretty much does everything, and simply mentioning God doesn't necessarily mean she's a young-Earth creationist.)
So. Aside from inviting the property owners to my student's thesis presentation (which we will definitely do), and sending them a copy of my student's thesis (microprobe data and all, heh)... where on earth should we start? Or should we start? Would it be rude?
Posted by Kim at 7:51 PM
Saturday, July 14, 2007
Sorry about being slow. Here's Where on (Google) Earth #30:
And here's an oblique view:
When you find it, tell me where it is, how you found it, and a little about the geology. I've turned off moderation on the comments, so if I'm away from the computer for most of a day (which is likely to happen), you can play through.
(Credit: Where on (Google) Earth is Brian's idea, and Ron has put together a site with all the previous locations (http://ron.outcrop.org/kml/WoGE.kmz).)
And, yes, I decided that I might as well use my real name on this blog, since it wouldn't really be that hard to figure out who I am.
Monday, July 9, 2007
Our well is out of water.
The guy who originally developed the property sent a letter around to the ten households who share the well, telling us about the situation, and blaming it on the relatively recent drilling for coal-bed methane beneath us.
The situation isn’t all that new – we’ve been having intermittent water crises for the past five years or so. What’s new, though, is that his letter coincided with a water judge’s ruling that methane producers must apply for groundwater well permits.
Coal-bed methane production certainly involves pumping out a lot of water. The methane adsorbs onto the coal, and is only released after a lot of the water is gone. And the drillers hydraulically fracture the rock to increase its permeability, and then pump more water out of it. Around the edges of the basin, where the coal crops out, landowners complain about an increase in methane seeps. And the dewatered coal has caught fire and is now burning underground in at least one place.
My groundwater comes from sedimentary rocks that fill a Laramide basin. The rocks aren’t really very permeable – there are some sandy layers, but they seem to be discontinuous (at least in road cuts), they’re poorly sorted, and they seem to have a lot of clays in them. And they are surrounded by mudstones. So even though the drillers pump out a lot of water, it’s possible that our mediocre “aquifer” isn’t hydrologically connected to the coal. Geologists from the Bureau of Land Management have made that argument in the past.
On the other hand, it’s possible that we get our water from interconnected fractures. (As a structural geologist, I get all excited about that possibility.) The ability of drilled wells to produce water varies a lot over short distances, enough that local dowsers can make a decent living telling people to drill in a slightly different spot. Maybe the sandstone is discontinuous and hard to hit, and maybe the water resides mostly in cracks. When I watched our well drillers work, I couldn’t figure it out.
And if the water comes from fractures, it’s possible that the cracks connect to the coal beds, and that the methane production has sucked our well dry. (But if that were the case, I would guess that our well water would have smelled like rotten eggs, like the methane seeps do. But our well had great water. When it had water, that is.)
There are other possible reasons why our well is dry. The population in our county has been growing at an outrageous rate. (The four new houses up-gradient from us were built since our well problems began, however, and there’s just a huge ranch beyond them. Down-gradient there’s BLM land. So the population growth doesn’t seem like a good explanation for my well, though it is probably important for other wells in the county.)
And then there’s our drought. The snows haven’t been as heavy, and the late-summer monsoon rains have been weak. This winter was much worse than the national news made it seem – we didn’t get the blizzards that kept shutting down Denver, for instance. March, especially, was warmer and drier than normal. And it was worse at my elevation – we never had to plow the driveway, there was so little snow. And the rocks that supply my water don’t extend all the way into the mountains – they end at a lower elevation, below the rain/snow line for most of this winters’ storms. They say this may be the beginning of a drought as bad as the one that drove the Ancestral Puebloans (aka Anasazi) away from Chaco Canyon – that global warming is likely to give us less winter snow, and earlier thaws, and less water overall. I worry that our water problems are only beginning.
So. Blame the gas companies? I’m skeptical of the BLM’s claims that it’s impossible for the water to be connected. I mean, the coal immediately underlies my aquifer. It’s not all that deep, really (and besides, I want to believe that brittle deformation is relevant to my everyday life). But I suspect that our real culprit is the drought (plus population growth). And that, unfortunately, is a much more difficult issue. The gas production in our basin is already dropping off. Global warming and local population growth, however, don’t seem likely to stop any time soon.
Friday, July 6, 2007
The West has been hot. Hot, hot, hot. Well, except for here; our July weather pattern arrived on Wednesday, and we're having these amazing afternoon thunderstorms. (Well, amazing for now; I'm doing lab work this week.)
In any case, when I saw CNN's headline about the weather (Stifling heat spreads throughout West), I had to check it out and see which West, exactly, was miserable.
As I read the story, this section stood out:
Air conditioners -- and even swamp coolers -- were predictably hot sellers at the hardware store.
"I'm telling you, it has been nuts," said Dennis VanDyke, a manager at Power Townsend in Helena. "The only thing I am getting calls for is air conditioners."
VanDyke said some people prefer swamp coolers, which use a fan and the condensation of water to cool the air, over the more power-hungry air conditioning units.
Ok. Let the nitpicking begin. Key point: it's the evaporation of water, not its condensation, that cools things off. It's all about latent heat: it takes energy to turn liquid water into water vapor, and as the energy gets sucked off to send those water molecules flying away, the surroundings cool. This is actually an important concept. It explains why 90 F is pleasant here and unbearable in New Orleans. It explains why exercise is more pleasant in an arid climate. And it explains very important things, like why hurricanes cool the ocean that feeds them.
What's weirder and more confusing is that condensation actually does the opposite: it warms its surroundings. This seems counterintuitive, especially for people like me who grew up in cold, humid places, and who know how cold dew can feel on the grass (or - shiver - on a tent). But the condensation of water to make clouds heats the air, high up, and can make rising air continue to rise.
So, anyway: CNN, you lose points. Sorry.
Second point: swamp coolers are really, umm, cool. They cool a house by evaporating water - that's it. They use a lot less energy than air conditioners do. They aren't an option for places with high humidity, but in a place where the humidity is often less than 10%, they're great. (I don't have one - I cool my house by keeping shades pulled during the day, and opening windows at night. But I think they're a great concept. Good way to reduce electricity bills, reduce one's carbon footprint, and so forth.)
(Aside: I think I might keep track of little errors in the media. They might make fun exam questions.)
Thursday, July 5, 2007
From the Denver Post:
Alyssa Heberton-Morimoto, a Masters student mapping for the Colorado Geological Survey, was murdered while waiting for her field partner to meet her for lunch.
I'm horrified. Yikes, that poor woman and her family. And her poor field partner, who heard the screams over her radio, and who hitched a ride with the murder suspect because her car keys were missing.
I've been in the habit of mapping in pairs - I've worked in grizzly country, and there are a lot of things that can happen alone and far from help. But most of them are things like sprained ankles and falls on steep slopes and, occasionally, bears or mountain lions. But murder. Yikes.
My male colleagues regularly do field work alone. I don't. And perhaps I'm wise, though significantly less productive.
(On the other hand... an acquaintance of mine was murdered, along with her female companion, on the Appalachian Trail more than 10 years ago. Two might not be enough for real strength in numbers.)
Posted by Kim at 12:33 PM
Tuesday, July 3, 2007
Today's astronomy picture of the day is a view of the rim of Victoria Crater, taken by the Opportunity rover as it descends into the crater. And I could swear that I'm looking at one of the big eolian sandstones from the Colorado Plateau. Moab on Mars?
I guess it isn't a major finding, seeing evidence for wind-blown sediment on Mars. But it's amazing to see sedimentary structures from another planet. And eolian sandstones are beautiful.
As students walked into my Earth Systems Science class on the first day of fall semester, 2005, they saw a satellite image I had just grabbed from NOAA’s website: Hurricane Katrina, aimed straight at New Orleans. It seemed like the perfect image to illustrate the relevance of studying Earth. But I’m a solid-earth geoscientist; I’ve never taken a class in Oceanography or Climatology or Meteorology. And when the science about hurricanes and global warming became big news, I wasn’t very well prepared to answer students’ questions about what scientists really think. Since then, I’ve read news reports, NOAA’s web page, articles in Science, Real Climate... and I’ve had trouble figuring out how all the pieces fit together.
Storm World, the new book by Chris Mooney, gives me the context I needed. It starts by tracing the history of ideas about hurricanes through the 19th and 20th centuries. One of Mooney’s central points is the difference in methodology and models, from the very beginning, between scientists who started with physically based models and scientists who started with observations. It’s a familiar pattern to this field geologist, who has heard Ernest Rutherford’s comments about physics vs. stamp-collecting in many different guises. But in the history of hurricane science, it’s clear that both approaches can provide insights, and both can miss the mark. For instance, in the 19th century, two key aspects of hurricanes were recognized by the two different groups: physics led to theorizing about the release of heat as clouds form, and observations led to descriptions of a hurricane’s circling winds. (It took recognition of the Coriolis effect to show that the two models could work together.) Although it is possible to follow the two approaches into the 21st century, the researchers interact, sometimes by attacking one another, and sometimes by picking up an idea from the other group and transforming it. (For instance, observations showed that hurricanes derive their power from warm ocean water – which leads to the big question addressed first by theoreticians: what happens if we warm the atmosphere and oceans?)
The book continues by tracing the debate over what effect (if any) global warming will have (or has already had) on hurricane strength. It covers the science, the personalities, and the media attention in 2005. All the while, it manages to be simultaneously even-handed and engaging. I don’t know why it works – the history and the science are both complicated, and the cast of characters is immense. And yet the story is woven together so neatly that I never felt the need for a time line or a chart showing the academic genealogy of the major players.
And now I have answers to a lot of my questions. What exactly is the Atlantic Multidecadal Oscillation, and why don't I understand the explanation on NOAA's website? (Answer: it's an alternate way of explaining recent warm temperatures in the tropical Atlantic, one that doesn't rely on global warming. It isn't clear whether there really is a cycle, or whether temperature changes from the 70's (cooler) to the 00's (warmer) are the result of natural processes or anthropogenic global warming.) Why does NOAA's website contradict articles in Science? (Answer: partly because there's argument over the articles, but also partly because of decisions by political appointees.) The history and politics of the science are fascinating, and have influenced the way in which the science is described to the general public. These are things I need to know - as a teacher, I also have the opportunity to frame discussions in particular ways, just as science journalists do. I haven't yet decided how I will change my discussion of climate in class, but I'm thinking that it may need a bit of an overhaul.
It is refreshing to read such an engaging account of science in action. I would recommend it to anyone who is interested in the history of science, in climate and weather, or in the interactions of science, the media, and public policy. And for anyone who, like me, teaches about weather and climate in the context of introductory science courses, the book is an absolute must-read.