life in the Southwest

Slumgullion movement due to atmospheric pressure?

khannula — Sun, 01 Nov 2009 16:48:13 +0000

Slumgullion movement due to atmospheric pressure?

Go to Dave's Landslide Blog for full details about this. I don't have access to the paper.

According to Dave Petley, there's a new paper in Nature Geoscience about the Slumgullion landslide. Slumgullion is in my greater neighborhood - it's in Colorado's San Juan Mountains, between Lake City (former home of Alferd Packer) and Creede (former home of Doc Holliday), and I think it's got the coolest name of any landslide (and possibly the coolest name of any geological feature). It's a strange landslide for its slow movement, and it's being monitored in excruciating detail by the US Geological Survey.

Warning: I haven't read the full paper - just the press release and Dave Petley's comments on it. So, with that caveat, here's why I think the paper is interesting, from the perspective of someone who teaches structural geology (faults, folds, etc.):

The paper concludes that changes in atmospheric pressure cause the small nightly movements of the slide. The explanation is that atmospheric pressure pushes down on both the soil and water. Increases in atmospheric pressure increase the friction that keeps the slide from moving; decreases in atmospheric pressure reduce friction, and allow the landslide to move. This implies an incredibly subtle balance of forces - atmospheric pressure isn't very large compared to the weight of water or soil or rock. And it also means that those things going on in the air are important to what happens below.

Dave pointed out that there was another paper in Nature this year that related changes in atmospheric pressure during typhoons to "slow earthquakes" in Taiwan. It's intriguing. (It does NOT support the concept of "earthquake weather" that Californians tend to bring up every October. Works for slow earthquakes on thrust faults during the extremely low air pressures of typhoons, because the orientation of the fault combined with the stress directions mean that pushing the rocks down decreases the chance of sliding. California's got the wrong fault orientations and stress directions for this to work.)

Intriguing, and perfect fodder for tomorrow's discussion of the stress conditions that reactivate faults. Thanks for the lecture help, Dave!

khannula Sun, 11/01/2009 - 11:48

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Really!? What sort of pressure changes are they talking about? I mean, 1 atmosphere of pressure at sea level is equivalent to the force of ~6 ft of rock (assuming density of 2.5 gm/cm^3). A typical difference in pressure distinguishing a high pressure center from a low pressure one is just a couple of percent, or an inch or two of rock-equivalence. Even if a tropical depression passed over, we're talking about a change equivalent to less than 6 inches of rock, and I can't image the day/night fluxuations to be more than inch at best (in rock equivalence).

At what depth below the surface is sliding occuring at? I would think that below a few feet the relative change in pressure would be pretty slight.

Like I said, I don't have a copy of the paper, so I don't know what depth they're talking about. There was a USGS report on the work published a few years ago, though, which probably has the full details of the geometry of the slide - more than Nature Geoscience would have room for. Dave Petley (who studies landslides) found the results surprising, but thought the modeling looked reasonable. (He also thought that there are only rare cases where air pressure could make a difference - that the slide would need to be essentially at the point of failure all the time.)

What IS this weird pollinating... thing?

khannula — Fri, 21 Aug 2009 19:08:31 +0000

What IS this weird pollinating... thing?

I've been trying to get some xeriscaping established this summer, and I've been very pleased with the plants that are growing. This one, Ceratostigma plumbaginoides, is supposed to become a groundcover, and it's spreading quite well. But with the flowers have come some interesting pollinating... things... that I can't identify.

The leaves in the picture are about a centimeter or two across, so that thing is pretty big. It moves like a hummingbird, hovering in place and then zipping to another flower. (In fact, when my kid was buzzed by one recently, he swore it had been a hummingbird.) It's got a long proboscis... thing... and antennae. My guess was some kind of a moth, but I've never seen anything like it.

I've seen it a number of times in the evening, but that's when we're out watering. I don't know if it pollinates during the day or not.

Whatever it is, it's cool, and I'm happy to have it hanging out in my garden.

(Photo credit: my other half.)

[Edit: my other half googled "bug that looks like a hummingbird" and found this: white-lined sphinx moth, aka "hummingbird moth". So I guess he didn't have to ask me to put the picture on the blog after all...]

khannula Fri, 08/21/2009 - 15:08

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wow

Definitely a moth of some type. Don't know what type.

It's a hawk moth! I love them so, and miss them since we no longer live in Colorado. I think it's Hiles lineata, the white-lined sphinx moth -- but I am not a qualified entomologist, so I will defer to practically anyone else's expert judgment...

that is a hawkmoth, also known as a sphinx moth. this particular specimen is a White-lined sphinx (Hyles lineata).

Check out http://leps.it. While it's based on European species, it may, in some cases, apply to your case. Search under the family Sphingidae.

Here you go,
http://bugguide.net/node/view/93791

Or here.
http://faculty.ucr.edu/~chappell/INW/arthropods/sphinxmoth.html

I'd call it a "hummingbird moth" because one day I was in the vacant lot next door and there was a "Weekly Reader" magazine laying there with an article about them. When I looked up from the magazine, there was one right there pollinating a flower. That was the first and last time I'd ever seen one or read about one until now.

I only found one match in my butterfly book from 1983. If they are indeed the same, then the name is Celerio lineata, one of the few kinds of butterflies that occur almost world-wide. But I have to admit I am totally untrained with identifying any kind of insects.

Grrlscientist has it. I confirm her id.

Hummingbird moth of some type. They're amazing to watch - just slightly smaller than female hummingbirds, their flight is an almost perfect match (even hovering!).

Silver Fox had a post on these back in May. I had never heard of them before that, but they are impressive. I'd love to see one IRL.

Aren't these amazing? I remember the first time I saw a hummingbird moth (not the white-line sphinx moth you saw, but a related variety). I was VERY disappointed when I realized it wasn't a real hummingbird.

This is probably what I saw, and as you see it looks very much like a Ruby-throated hummingbird: http://www.silkmoths.bizland.com/hthysbe.htm .

Here's the one we saw south of Goldfield, NV, earlier this year - hummingbird moth or white-lined sphinx moth.

Wow! What a neat moth!

Sphinx moths are common on Colorado's front range. As visitors to the flower garden, they are lovely.

But before you get too enthusiastic about how lovely they are, you need to know that they start out life in the larval stage as tomato hornworms, which can get up to 4 inches or so long and are major munchers of tomato, potato and pepper plants.

Online assignments and the digital divide

khannula — Mon, 17 Aug 2009 05:00:00 +0000

Online assignments and the digital divide

I've recently taken to using the magic of the internet to give my students access to readings, assignments, and images outside of class. It's great - if my sophomores lose their map, they can print another one. If a student misses class, there's no excuse not to do the homework anyway. If students can't draw their own pictures, they can print out images and study them on their own. And it's possible to go even further with online teaching materials - to have students prepare for class by doing online readings, or watching a video, or listening to a podcast, and then responding to online questions (which give them a grade-related reason to do the class prep work).

But even though students can get access to the files from any place with an internet connection, they don't all have equal access to the course materials. And the class prep work can impose burdens beyond required textbook reading.

To understand why, look at this map posted last February on the Daily Yonder:

The map shows the proportion of farmers who have broad-band internet access in various parts of the country. (For some reason there's a census of agriculture that collects this information. It's not a perfect picture of rural internet access, but it gives a sense of it.) My part of the country is fairly well wired - in many Colorado mountain towns, 60 to 70% of people have broadband access. My county isn't in that upper tier - it's only 30 to 40% wired, but the proportion in town (where DSL and cable internet have been available for years, and where the coffee shops have free wifi) is probably higher.

But look south and west. That pink area in eastern Arizona - only 4 to 10% of farmers have broadband there. Some of my students come from there, or from the adjacent part of New Mexico. There are wide stretches of that area with no cell phone service, let along high-speed internet. When we talk about "kids these days," with their text messaging and Facebook pages, we're talking about people who have had access to things that aren't available everywhere in the US.

And even those people who live in areas served by high-speed internet might not be able to afford it. According to an article posted in June, a third of people (with internet access) in the US don't have broadband access. Some of those people are my students, as well - only freshmen are required to live in the dorms, and when I ask how many people can't access the internet from home, there are always a few students who raise their hands. (And the single parents who have returned to school to finish their degrees can't just run down to the coffee shop like some college students can.)

I don't want to exclude students just because they haven't had the experience using Google or text messaging that their peers have had, or because they don't have internet access in their home off-campus. If I require using technology outside the classroom, I'm making an assumption that students have access to it (and the expertise necessary to use it). So I prefer to give students access to technology in class, where they have the opportunity to learn about it (from me, from their peers, from experimenting).

This wouldn't be an issue at a school where all the students live in networked dorms, have laptop computers, and are the age and social class to have played with computers since they were small. But my campus is more diverse than that. And it's important to teach to the students one has, not to someone's conception of what a 21st century college student is supposed to be.

[Side note: I've changed my commenting policy to deal with the huge amount of spam I've been getting. From now on, I'm going to moderate comments, and only let through ones that I'm sure are legitimate. Comments may take more than 8 to 10 hours to appear, because I'm not going to deal with them from work, and I might mistake some real comments for spam - one spammer posted a chunk of a Real Climate post lately! But hopefully the spam will decrease.]

khannula Mon, 08/17/2009 - 01:00

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Thank you for the graphic illustration. I was reminded of the reality while on vacation (Glacier National Park, photos should be going up at my blog one of these days). Hadn't really thought about how it could apply to education, though. And that's a very big point given the presumptions about "it's all out there (internet)" equating to 'everybody can get it'.

Beast in the... elementary school playground?

khannula — Tue, 04 Aug 2009 20:03:20 +0000

Beast in the... elementary school playground?

There was a mountain lion in the courtyard of a local elementary school playground today.

A mountain lion.

At the elementary school.

A neighbor called the police, who called the Department of Wildlife, who shot the mountain lion. A young male, about 75 pounds, probably recently headed out on its own. Apparently that's the age they usually are when the DOW kills them for wandering around in town.

I just finished read The Beast in the Garden, this year's common reading at the college, so the story sounds eerily familiar. The Beast in the Garden is about the mountain lions that began showing up in Boulder in the late 80's. First there was open space, and people moving to the edge of the mountains to live closer to nature. Then there were deer. And more deer. Deer eating vegetables out of gardens and apples off trees and acting like those chipmunks you see at state parks, only a lot bigger and more damaging to a car when you hit one. And then the cougars started appearing - first sightings in the canyons at the urban-wildland interface, then eating dogs, then braver and braver until they were actually wandering the streets of Boulder's University district on the first weekend of college.

And then a mountain lion killed and ate a high school kid while he was out for a run.

Durango's lucky that the Department of Wildlife is aware that cougars can become habituated to humans, can lose their fear. Because Durango is cougar country - a growing community spreading into the pinyons and Ponderosas, with deer that give birth to twin fawns in the middle of campus and lots of rugged terrain where a big cat can hang out and wait for prey. (I like to go on trail runs in that terrain. So do a lot of other people.) For the past few years, there have been sightings of cougars up by the college. Last summer, my neighbor saw one walk through her yard one night, and two cats were killed in town. This year, a cougar was hanging out in an elementary school playground.

Before I read The Beast in the Garden, I read another book about kids and nature: Last Child in the Woods. It argues that we keep our kids inside because of an unreasonable fear of nature, and that kids need to go back to the good old days of the 50's and 60's, like when the author was growing up, when kids could build treehouses and wander around woods and fields without worrying.

After I read The Beast in the Garden, I wondered whether that golden age that Last Child recalls was something unnatural - a time that could exist only because the previous few generations had done such a good job of exterminating the predators.

I played in the woods as a kid. I grew up in Maine, with woods on two sides and a lake on the other. I had nightmares about bears and was afraid that the Loch Ness Monster's evil twin, Nasty Sebasty, would get me. But I barely even saw deer. Maybe at dawn, sneaking apples in the fall, but not in the middle of the day. There were squirrels, and chipmunks, and loons, but no big mammals - at least, not where people lived.

When I lived in Vermont in the 90's, things were starting to change. There were more deer, though they were still shy. And then there were coyotes. First just rumors of them, then choruses singing through the night. Other animals were coming back, too. I knew someone who claimed to have seen a marten. And people said that there was a catamount, an eastern cougar, somewhere in the Green Mountains.

And now I live in the second biggest town I've ever lived in (after Palo Alto), and there are deer moseying down the street in mid-day, and a cougar in the playground of an elementary school.

There's a part of me that's on the side of Aldo Leopold and Edward Abbey, that's glad that the cougars are back. And then there's the part of me that says: don't come near my kid.

I know that we're encroaching on the cougars' territory. But I want my kid to go outside, too, so I'm glad the Department of Wildlife is willing to shoot cougars to kill.

khannula Tue, 08/04/2009 - 16:03

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I lived in Boulder at that time, and used to think that the big kitty problem was only a problem of encroachment and human behaviors (like leaving your dogs outside at night). Now that I live in a major north-south wildlife corridor, I'm very cautious and circumspect about the kid being in the yard without my being able to see her and/or the dog. We've had mountain lion mamas with kittens in years past, and a neighbor found a bobcat in the back of one of his vehicles. I'm this close to asking the SO to cut down the apple trees as they are a bear attractant, especially in lean years. Like you, I'm happy to live here and give my child the wonder of nature, but I have no problem calling the local game warden when needed.

What do you make of a cougar in Chicago, though?

To what extent is not shooting enough deer an issue here?

Nothing is ever perfectly safe. One kid was killed by a cougar, but how many kids are killed by cars, drown, fall off cliffs etc? Nature was never perfectly safe, but perhaps people used to have a more realistic idea of the risks involved, which are actually rather small.

It was I think in 2004 that a cougar killed a mule deer on the south-facing porch of a building at Jet Propulsion Laboratory. The hoof marks on the concrete showed where the muley had struggled, and where the blood trail began. No one ever turned up the carcass.

A cougar in Chicago? Wow.

LL: I think that not shooting enough deer is part of the problem. Though it's more complicated. In Durango (unlike in Boulder), there's hunting allowed in the open space around town. (Durango borders BLM and National Forest land.) I've seen hunters on the trails where I run. But in town itself, people don't hunt. (Too many houses, too close together.) So the deer find the town to be the safest place - lots of food (because of irrigation, there's more vegetation in town - non-native trees, aspens that normally would grow higher, grass, flowers, vegetable gardens...), and they aren't hunted in town (by humans or by other animals). The biggest danger in town is getting hit by cars (and I've actually seen deer looking and waiting for cars before crossing the road). So I don't know the solution - hunting in town? Chasing deer whenever we see them (rather than telling everyone not to bother the fawns at the college)?

I've had multiple encounters with wildlife around my house, and I live near the center of town (I'm in New Hampshire). I've seen at least one deer running through my yard (neighbors have reported other sightings at times when I was away at work), and one year a beaver built a dam on the small stream in my back yard. Two or three years ago there were multiple sightings of a bear within a mile of my house.

Development patterns in the last 60 years have basically assured that we will have more of these incidents. Of course deer are going to hang out in populated areas--they are well established in east coast suburbia, which provides plenty of ornamental shrubs to munch on as well as protection from predators and a lack of hunting (suburbia is also prime lawyer habitat, and you don't want to shoot a lawyer's kid, even by accident). We've forgotten in this country why the rest of the world lives in villages--this is one reason.

A wild cougar in Chicago and a tony suburb? More likely someone's "pet" either escaped or was turned loose. Think not? Check out: http://www.greatcatsofindiana.org/rescue_info.htm

Note from Boulder: Just to clarify, the young man killed by the Mt. Lion, 18-yr old Scott Lancaster, met his unfortunate end in rural Idaho Springs, 40 km as the crow flies from urban Boulder. While certainly possible, there is no evidence this cat's home range was the Boulder open space. This fact seems to undermine the central thesis of the book that human encroachment on cat habitat + lots more deer = dead kids. That being said, cat sightings are quite common around here, but thankfully predation on humans much less so. Keefover-Ring wrote a couple of pieces addressing this in much more detail. http://findarticles.com/p/articles/mi_hb3153/is_4_35/ai_n29235828/

Jon - Yes, but Idaho Springs is only about 20 km away from the Eldorado Canyon area, where one set of lion encounters (in which a mountain lion ate a bunch of dogs) occurred. And mountain lion ranges are pretty big, even when the cats are established. Idaho Springs feels far from Boulder (especially if you are getting up in the morning to drive to a trailhead, or to head into the mountains for field work*), but for an animal that doesn't get stuck in traffic, it's not that far.

* I lived in Boulder and worked at the USGS in Lakewood for a summer between college and grad school - in fact, I was doing trail runs in the hills west of Boulder during the time covered in the book. So I know how far the distances feel. (And I know that I was completely unaware of any mountain lions the entire time I was there - it wasn't as if there was a mountain lion hiding behind every bush. And there isn't in Durango now, either.)

These things always make me sad because I'm one of those people that really wants people and nature to get along and this is one of the biggest questions that I just don't have an answer for: how do we live with things like mountain lions?

I grew up in a small farming town in northwestern Connecticut and deer were very common, along with coyotes and raccoons, rabbits, and some fox. We had a bear living in our backyard (still do!) and so we were told to make a lot of noise out in the woods, and be careful, but never to not go out and no one ever got hurt.

But that clearly isn't always the case. It would be amazing if we could both save the cougars and wolves, and be able to go out and enjoy nature without first all getting hunting permits and shotguns.

Kim,

I guess my main complaint with "Beast in the Garden" was the tone of "ZOMG the cats are coming for the Boulder KIDZ!" I'm aware that cats can easily range the 20 km from Eldorado Canyon to Idaho Springs, and you're right, it's often quicker to make that trip on foot. But there is a thriving cat population in Gilpin and Clear Creek Counties between Boulder and Idaho Springs. This area fits the textbook definition of urban/wildland interface. I'm actually surprised more fatal (for people) conflicts between cats and people haven't happened there or elsewhere.

Best, Jon

Best, Jonathan

There are too many of us and not enough wild space left for the critters and native plants. And too many of the too many of us want to live in big houses on big lots far away from others out on the fringes of suburbia...where we are going to come smack up against the remnants of wildlife struggling to live on the itty bitty bits of land that haven't been paved over yet.

These kinds of stories depress the hell out of me. There's no good solution, not as long as humans are still around in such large numbers, because we are always going to be encroaching on space that the animals don't know isn't theirs anymore.

I'm willing to accept the fact that some creatures eat meat, and humans are made of meat. You don't see many cows killing us because some humans eat cows, I don't think that we should be making a habit of killing cougars because some cougars have been willing to eat some humans. More of us are in danger from being killed by cars than by cougars. Death is a natural part of life, and I'd far rather that when I'm dead some critter got the use of my meat for food than to have my body embalmed and rendered inedible and no longer part of the life cycle. Your mileage may vary.

In this area (and in the areas where the two cougars were killed last summer), it isn't a case of humans recently moving into cougar territory. They were in the middle of town, in the areas that have been occupied by humans for... well, this is Colorado, so the history of Anglos doesn't go back that far, but I would guess that some of the houses in that neighborhood are 100 years old. In this case, the cougars are expanding back into territory from which they had been driven out. (The Beast in the Garden quotes a cougar population in the range of 125 to 1500 in the 1960's-1970's; the CO Division of Wildlife estimates the population is now 3000 to 7000. Difficult animals to count, but the population appears to be growing.)

There's something very cool about animals making an ecosystem of places where humans live. Not just cougars, but deer and bears and coyotes and Canada geese all seem to have adapted in some way or another to places where people live. It's great that the end of the campaigns to exterminate animals like the cougar have allowed the populations to grow and expand. (Especially given that humans are so good at making species go extinct.)

But. I think it's reasonable for social animals like humans to defend the places where they raise their young. We're not the only animals to behave in such a way.

I'll grant the cougars the mountain bike trails, but the elementary school playground? I would prefer to discourage a big cat from claiming that as part of its territory.

I live in Little Britain, Ontario, Canada. Half way between Lindsay and Port Perry, on the north shore of Lake Scugog. We have mountain lions in our community, I have seen one. Valentia, just 4km down the road, celebrated it's 200th Birthday in 2007. Point being, people have lived here for many years - not like we are encroaching on the mountain lion's territory. It was interesting and surprising to read about this case, the department of wildlife official declaring publically (in the newspaper) that "we don't want lions in town." Here in Ontario, officials tend to deny the existance of mountain lions in Ontario, yet at the same time,request funds to study this lion they claim does not exist here? It is my understanding that the North American Mountain Lion (cougar,puma) is in fact the 4th largest lion on the planet, perhaps worth mentioning in conversations surrounding the issue of dangerous wildlife co-existing within populated communities? The most recent and perhaps most relevent example of such would be the recent mountain lion attacks in Vancouver B.C., where several dogs and humans were attcked. Even more interesting would be the recent nuisence lions that were shot and killed by police in central Canada, some of which were tagged and radio collared in the USA some 1200 km to the south of where they were terminated. I think the biggest question that I have about mountain lions is this: If this lion that wildlife officials claims to be endangered(on the endangered species list)and so near to possable extintion, is attacking so frequently, being sighted so frequently, then perhaps officials are possably fudging the statistics? How can a near extinct lion be sighted and attack so frequently? I believe mountain lion experts and wildlife officials are trying to hoodwink the public with respect to their place and numbers in our communities in North America. Protecting and preserving nature is a noble cause, however, lions in our backyards and our children's schoolyards are a predictable and preventable threat that needs to be dealt with by due diligence, transparancy, and in an open public manner. Might all concerned parties carefully consider making public safety the "priority" ? Would it be unreasonable to suggest that the mountain lion issue is not getting the shared, both US and Canadian, attention that it deserves? Thank you for taking the time to carefully consider my comments.

Is trapping allowed in CO? As long as the lawyer kids don't lick salt...

People are such cowards. We kill everything that makes us a little nervous. On the other hand we ignore some real threats. Kids are in far greater danger from large dogs and cars than from mountain lions. There are about 7 billion people on this little planet and we are driving many other animals to extinction. Yet we fear nature!!!! Maybe if we were not such cowards we would accept a little risk so that some other animals can exist.

Kim - You might be interested in what the WA state DFW has been doing with respect to cougars and kids. Project Cougars and Teaching (CAT) is part population study/modeling and part environmental ed for the school kids and has the added benefits of getting the kids out there educating their community about how to deal/coexist with cougars in the area. My impression is that people estimated that were orders of magnitude fewer cougars in their immediate environment than there actually are. While they haven't had quite the same problems with cougars on the playgrounds they are hoping that this program will be the first step in preventing cougars from becoming so emboldened as they are in your area.

As a Colorado native, I will say that we don't belong here; they do. I hate Durango as much as any city in the state. We deserve to be eaten.

The parents should take care of kids while they play with pets or others.

A couple years ago snomobilers came across a dead deer, dangling over a tree branch, 20 feet off of the ground. Like the stuff you see on Discovery Channel when the Leaperd drags the Impala kill up the tree so he doesn't have to share with the hyheena's. Only this is where our kids wait for the school bus, only a short distance from an elementary school - kinda scarey when you think about it? Statistically our kids our safe, unless your own kid becomes that rare statistic in the belly of a lion that wildlife officials claim are not a threat to public safety??? Could you imagine the search effort that would take place if a mountain lion escaped from a zoo, yet, the wild mountain lions in our communities only manage to create a one time local newspaper type warning, like a "don't feed the bears" campaign? Perhaps the wild mountain lions don't have that "liability concern" attached that gets disguised as concern for public safety all to often?

Anchorage (just 30 minutes from Alaska)has bears (black and brown) and moose (killed more people than bears do) nearly everywhere. The approach has been to leave them alone; scare them off; teach people how to behave. Very few have to be shot (bears or people). Out on the tundra, it is the dogs that kill and maim kids.

In Los Alamos, NM was the same-- coyotes, black bears, and deer/elk hop fences and stroll the parking lots. The lions stay off the streets, though.

I was told by NM wildlife folks to leave a lion in the neighborhood because it will keep others out. Losing a few sheep (protection money) meant not losing a whole lot of sheep to new encroachers trying to scope out the new neighborhood.

One possible solution to too many deer in town is archery hunting. I am sure that CO has plenty of hunters who would be willing to perform this service for free. In my experience, however, many urban people do not tolerate the taking of their "pet deer" by hunters.

Why I didn't finish my spring reading list

khannula — Wed, 10 Jun 2009 04:40:53 +0000

Why I didn't finish my spring reading list

There's a meme going around about plans for summer reading. While I was reading Sciencewoman's list, I realized that I was avoiding the meme. See, I didn't even manage to finish my spring reading list, so I'm not ready to talk about big plans for the summer.

I had good intentions. I read Dirt: the erosion of civilizations. I bought Last Child in the Woods, and brought it along on my spring break travels. And... I didn't finish it.

Here's the gist of the book: kids should go outside and play in wild, overgrown places. Really, they should. They'll be happier and healthier and more creative and more resilient and more likely to be scientists. Now, I'm an easy audience for this book - I'm a field geologist, and my formative experiences included things like playing in the woods behind my house and backpacking along the Appalachian Trail. And I've seen studies that suggest that people who become geologists had childhoods like mine.

So there I was, sitting in the front seat of our truck, driving into Arizona, reading this book that talked about how Americans spend too much time driving to get to places and not enough time exploring them. And my son was sitting behind me, drawing pictures on his pad of paper and flipping through his books. Is it any wonder that I kept putting the book down and talking to him about what we were driving through? Or that we stopped at Canyon de Chelly and let him use a stick to create his version of a sand painting? Or that, when we finally got to Petrified Forest National Park, we raced around a short trail and didn't spend nearly enough time in the museum with the archosaurs?

Note: you're not supposed to do things like this on the petrified trees.

We spent a half a day at Meteor Crater, and half a day in Flagstaff, and then we went to the Grand Canyon. But we didn't camp - we stayed in a hotel about a half an hour from the park entrance, because we were worried that it might be cold at night for a kid with a cheap sleeping bag. And although the Trail of Time is great, it's paved, and not exactly a place for getting in touch with Nature. So while we waited for my husband to finish his epic run-hike, we hung out in some Ponderosas near the lot where we parked. It was perfect. I sat and read Last Child in the Woods; my kid ran around with a stick, pretending to blast space aliens or something. There was even a fallen-over tree that made a perfect space ship.

And then it happened. There was this crash, and a thud, and one of those screams. The screams that say "I'm really hurt, or maybe a little hurt and really scared, but I don't know and I NEED YOU RIGHT NOW." He had fallen off the tree, and landed hard on one side, and was bleeding from at least three different body parts.

It took a while to make sure that this was a case of "a little hurt and really scared," and even longer to clean off the scrapes. My husband got back in time to admire the wounds without seeing the tears, and we went back to the hotel.

We played outside around a tree in front of the hotel, but I didn't try to read the book again for several months.

Not the crashing spaceship tree. I didn't manage to take a picture of that one, for some strange reason.

khannula Wed, 06/10/2009 - 00:40

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life in the Southwest

I made that same trip, Petrified Forest (Painted Desert), Meteor Crater and Grand Canyon (didn't go to Canyon de Chelly) as a 10 year old, in the early 60's. It is one of the most memorable times of my childhood. The Meteor Crater made the biggest impression on me, I could not get over how big a chunk of rock must have fallen from the sky to make that hole.

And at the Petrified Forest, if they still have the sign that says you will have bad luck if you take piece of petrified wood with you, I have it say it is not true. I have had a really good life.

Oh, and I grew up to become a scientist.

The rangers at Hawai'i Volcanoes National Park tell tourists not to take lava or PÃ©lÃ©'s Tears because it's against the law. They used to say that it would bring bad luck to the thief. Then they found that people were mailing back the stolen lava or PÃ©lÃ©'s Tears if they had a run of bad luck, and the rangers don't want mailed-back stuff either.

That's an interesting refelction about what people actually hear. Clearly they do hear the rangers telling them not to steal and do it anyway, then afterwards get remorseful about Madam PÃ©lÃ©. There's probably a dissertation's worth of psychology there!

Repost from old blog: the sound of mylonites

khannula — Thu, 07 May 2009 02:00:00 +0000

Repost from old blog: the sound of mylonites

I'm neck-deep in a five-week summer class, and spending my evenings reading for class prep and thinking about how to run discussions. So I'm on a blogging semi-hiatus, at least until I've got an hour or two free of other commitments. In the meantime, I'll occasionally post some of my old favorites. This one was my first blog post ever, and was included in the 2007 Open Lab.

NPR has had this series, off and on, in which listeners record interesting sounds and then explain them on the air. I didn't have a recording device with me last weekend, but I literally stumbled across some of the most musical rocks I have ever heard: the Snake Range dÃ©collement.

I had never been to the Snake Range before, although it loomed much larger than its true elevation over my grad school career. The Snake Range is in easternmost Nevada, nearly on the Utah border, and is home to Great Basin National Park. And it's crossed by US 50, the "loneliest road," the road that continues west across the Basin and Range after I-70 ends. And in the 80's and early 90's, it was a case study for controversies over how continental crust stretches. It's a metamorphic core complex, a range with a core of metamorphic rocks overlain by a veneer of faulted and thinned sedimentary rocks. The boundary between the metamorphic and sedimentary rocks has been called a thrust fault, a low-angle normal fault, and an exhumed ductile-brittle transition. The metamorphic rocks are only around one-fifth their original thickness - pebbles stretched to pencils, thick beds of quartzite turned into mylonitic flagstone that is quarried into lovely slabs, thin and strong, with streaks of silver muscovite shimmering on their surfaces.

I was scouting out the area for a class field trip. I'm teaching Advanced Structural Geology for the first time, and I wanted to take students to see some classic fault and shear zone rocks. The Snake Range dÃ©collement is an amazing example of a mylonite, a rock in which the minerals have been shrunk and strung out by deformation within the crystal lattices themselves. Hard to explain to students the first time, and darn hard to identify in the field, and important to be able to recognize and interpret. And very, very cool.

The rocks were everything I had hoped. Perfectly exposed, with beautiful structures. Easy to find, easy to look at. I climbed to the ridgeline, enjoyed the view, and then headed down.

And then I heard something I hadn't expected. Not the rattle of a snake -- they don't call it the Snake Range for nothing! -- but a musical sound from below my feet. The thin slabs of quartzite knocked against one another, and each differently sized rock rang with a different tone. It was too resonant to remind me of wind chimes. It sounded, for all the world, as if I were dancing across a xylophone.

I wish I could have recorded it. I was sliding down the ductile-brittle transition. And it was singing to me.

It was delightful.

Edit: If you want to visit this site, it is described in at least two field trip guides:

Miller, E.L., Gans, P.B., and Lee, J., 1987, The Snake Range decollement, eastern Nevada, in Hill, Mason L., ed., Cordilleran section of the Geological Society of America Centennial Field Guide, p. 77-82.

and in more detail here:

Gans, P.B., and Miller, E.L., 1983, Field trip 6; Style of mid-Tertiary extension in east-central Nevada, in Gurgel, Klaus D., Geologic excursions in the Overthrust Belt and metamorphic core complexes of the Intermountain region; Guidebook, Part I: Special Studies - Utah Geological and Mineral Survey, v.59, p.107-16.

khannula Wed, 05/06/2009 - 22:00

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life in the Southwest

structural geology

Signs of spring (?)

khannula — Thu, 16 Apr 2009 07:04:08 +0000

Signs of spring (?)

Last night, we were having another one of those incredible dust storms that have been blowing in this spring (and which may be decimating the spring snowpack).

This morning, I woke up to this:

I was happy to see it - it will melt by the end of the day, and will keep the soil from being so incredibly dry.

I'm not sure this guy is so happy, though:

khannula Thu, 04/16/2009 - 03:04

Tags

life in the Southwest

phenology

Flowering aspen

khannula — Fri, 03 Apr 2009 19:24:56 +0000

Flowering aspen

I've been watching an aspen in my front yard this spring, and sending data to the National Phenology Network. (That's phenology, the study of recurring plant and animals phases, not phrenology.) We've had warm weather, cold weather, and windy weather, and blooming violets, crocuses, and dwarf irises, but the aspens haven't done much.

Until now. My aspen is blooming. Kind of.

There aren't any leaves yet, but this morning I noticed some things that reminded me of the fuzz on pussy willows back in Maine. So this afternoon, I took a closer look, and picked one. And... I think that must be the aspen's flower. It looks like a fuzzy caterpillar.

I don't know why I thought the leaves would come out first. They don't for pussy willows, though most of the native shrubs in the pinyon-juniper woods leaf out first, and flower when it gets a bit warmer. But those shrubs have flowers that are pollinated by... I think bees and hummingbirds. The aspens appear to be pollinated by the wind (which is especially strong today), though they mostly propagate by root suckers. I hope I'm not going to be allergic to aspen pollen, now that I live amongst them.

The NPN data sheets ask whether the tree has male or female flowers. I have no idea how to tell. Anyone know?

khannula Fri, 04/03/2009 - 15:24

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life in the Southwest

phenology

For illustrations of male and female flowers see http://www.nesbrec.org.uk/articles/SEXING%20ASPEN%205.pdf.
If the URL is munged Google "sexing aspen trees" to find it.

Pictures are P.tremula (European aspen) but P. tremuloides looks similar.

Since that bit of slang has two uses that, in at least some places, occur equally, I'll point out that it's referring to the cat. Although one could make the case for merkins, I suppose.

What I remember from a spring in the Montana Rockies was that the male catkins were long and dangly and the females were short and stout. Male flowers come first I think so they can dry then the females and I think both occur on our quaking aspen. So you might wait and see if another kind of catkin comes along.

That looks short and stout but the violet-ridged thingamabobs look like pollen.

Those are purple anthers that will shed pollen. Many wind pollinated trees disperse pollen before they leaf out because all those green flags get in the way of pollen dispersal. Most people just don't notice such trees flowering because lacking colorful attractants for pollinators, the flowers go unnoticed. In some you have to look very closely to find the female flowers, e.g., filberts. Although quite common, designating seed plants "male" or "female" is technically incorrect. You see each pollen grain is actually a male organism. And hidden with seed producing flowers is a corresponding female organism, which is not the tree itself. They even have different ploidy levels.

Aspen is dioecious, meaning that male and female flowers are on separate plants.

Your tree has male flowers, and it will only have male flowers. Females will be on a different tree.

A billion years is a long way to walk

khannula — Thu, 02 Apr 2009 20:55:56 +0000

A billion years is a long way to walk

My husband and I both had goals for our visit to the Grand Canyon at the beginning of this week. He wanted to give himself a workout that would leave him feeling sore all week. I wanted to check out the Trail of Time, an exhibit that some of my colleagues from New Mexico and Arizona had been developing. I didn't know whether it was complete, or where it started, but I'd been hearing Karl Karlstrom and Laurie Crossey talk about it for years.

The rangers working at the main visitor center had heard about it at a briefing, and had some pamphlets hidden behind their desk, but weren't quite sure exactly where it started. They knew it was along part of the Rim Trail , and it sounded like it was near the Bright Angel trailhead (where my husband wanted to go, to start burning out his calves), so we parked, sent my husband on his way, and started wandering along the trail.

The trail isn't very obvious. Right now, it consists of a series of metal plates put in the ground every ten meters, and smaller metal circles every meter. The plan is to create a hikeable geologic time scale, at a scale of 1 meter = 1 million years, complete with signs about the geology. They've got the scale in place now, and since I had heard Karl and Laurie talk about the geology, I could fill some of the story in for myself.

The oldest plates that we found were for about 1940 million years, somewhere near Vercamp's Visitor Center. They get gradually younger toward the east, so as we hiked, we walked from the past towards the present day.

The oldest rocks in the Grand Canyon are around 1840 million years old. They, and similar rocks (such as the oldest metamorphic rocks in the mountains north of Durango) record the growth of ancestral North America by collisions with chains of volcanic islands.

Sometime around 1700 million years ago, a mountain-building event called the Yavapai Orogeny occurred. Well, we assume it built mountains. It certainly deformed and metamorphosed the rocks, and melted them to form some granites. And from the 1720-million-year marker, you can see some of those old rocks, way down at the bottom of the canyon, but the view of them is better further along the trail.

After that... well, there's evidence for other stuff happening elsewhere in the Southwest, but in the Grand Canyon, those metamorphic rocks were gradually being unroofed. And I mean gradually. It's easy to throw around Precambrian ages, but it's harder to think about what they mean. The next youngest rocks, the Grand Canyon Supergroup, were deposited starting around 1200 million years ago. That's around 500 million years after the older rocks were metamorphosed. For comparison, if we went back 500 million years before today, there would be trilobites doing whatever squiggly things trilobites did, and Pangea wouldn't even have begun to come together. And if that perspective doesn't help, you can walk that 500 million years with a five-year-old who wants ice cream.

You can't actually see the Grand Canyon Supergroup from the 1200-million-year marker, but it's visible below all the flat-lying rocks from viewpoints further to the east.

And then there's another gap. There are other tilted rocks above the Grand Canyon Supergroup, rocks related to the separation of North America from whatever was west of it around 800 million years ago. But we didn't make it to 800 million years ago. We didn't make it to the Cambrian explosion, a little after 600 million years ago. We didn't make it to the first land plants. We didn't make it to the age of the rocks were were walking on, at around 250 million years. We didn't make it to dinosaurs, or the formation of the Rocky Mountains, or any of the ages proposed for carving the Grand Canyon itself.

We got to 1000 million years - one billion years - and that was enough.

One billion years is a long way to hike when you've been promised ice cream.

khannula Thu, 04/02/2009 - 16:55

Tags

geologic history

geologic time

life in the Southwest

Remarkable preservation in that last photo!

Is there a shuttle bus to take you across unconformities?

Nice post. I for one can never get enough of Grand Canyon photos. Love that last photo, especially!

Ooooh! That second big picture is lovely. Now I want to go hiking!

Lab Lemming - There's a shuttle bus that goes from the Yavapai Observation Station (or 0 million years) back to Grand Canyon Village (including Bright Angel Lodge, where the ice cream was). So I think we could have walked less distance if we had kept going, rather than turning around. But the Small Human was balking, and I didn't want him to have bad memories of the geologic time scale. (Especially given that he could have gotten ice cream in 6 mm if the young earth creationists had made the trail.)

But as an educational tool, I kind of like having to walk through all that time represented by the unconformities. There's a lot missing, and it's hard to get that across.

On our field trip in March, I stood on the Great Unconformity just outside of Vegas with gneisses of the Vishnu Group under my right hand and Cambrian sedimentary rocks on the left. It was amazing to know there was 1.2 Gya of history missing between one and the other. But if you are ever in Vegas and want to visit, the area is very, very sketchy!

Small child for scale?

Would that pass peer review?

I figure if George Davis used his kids for scale in his structure textbook, I can use kid pictures in a blog. :D

Thanks for the marvellous pictures of the Grand Canyon.

A billion years is a long way to walk...
... and 4-plus billion years is even further to run.

Here's a geological perspective on the London Marathon ...

Best wishes from England, and keep enjoying your rocks!

Odd day to come back from vacation

khannula — Wed, 01 Apr 2009 18:43:46 +0000

Odd day to come back from vacation

It's the Small Human's spring break, which means all kinds of work-juggling. The family took off for four days and went to the part of Arizona which is not apparently being auctioned off on e-Bay to balance the state's budget.

It's strange enough driving through eastern Arizona during daylight savings time - most of the state doesn't observe it, but the Navajo reservation does, and the edges of the reservation are a patchwork of state, BLM, reservation, and private land. I had enough trouble keeping track of the time, let alone the date.

I'll try to do some real blogging about it (because there are lots of rocks there, as you can see). But maybe I'll wait for a day.

khannula Wed, 04/01/2009 - 14:43

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life in the Southwest

Testing format of my comments.

Kids of geologists take the best vacations!