Thursday, August 21, 2008

Sylvan Pass, Yellowstone

yellowstone_ice_sign

...No kidding!

This photo was taken in early June, when I drove through Yellowstone for the first time this summer... there was still snow eight feet deep along Sylvan Pass at that time!

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Monday, August 4, 2008

Examining life in extreme environments

A quick note here, just for the sake of completeness, on my final MSSE class of the summer: "Examining Life in Extreme Environments." This was a cool class, but structured in a different way from my other MSSE courses: it was set up more like a conference, with a variety of different speakers on different topics, interspersed with activities. The organizers, Susan Kelly and Monica Brelsford used a grant from NASA to help fund the course, which meant they had the money to fly speakers in from NASA Ames, the University of New Mexico, and the Wrigley Marine Science Center on Catalina Island, California. We also had a presentation piped in from Woods Hole. The goal of the class was to look at living organisms that manage to survive in 'extreme' environments, like really salty, really hot, really cold, really acidic, and so forth. Why study these bacteria and archaea? We're hoping they will give us insights into (a) the origins of life on Earth, and (b) the possibility of life on other planets or moons elsewhere in the universe. We had a field trip to Yellowstone National Park to look at microbial mats; we looked at cultures of hyperthermophiles; we listened to excellent talks by Mark Young (viruses as a source of genetic diversity), Ed Adams (new subzero lab tour), and Robert Szilagyi (thermodynamics of the origin of life). As you can see, it was pretty diverse -- all week long, always something new and interesting. I really enjoyed it!

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Saturday, July 19, 2008

Wildlife Ecology of Yellowstone

Back in Bozeman again after a great four day stint in Yellowstone National Park. I was up in the Lamar Valley ("Serengeti of North America"), checking out megafauna as part of my "Wildlife Ecology of the Greater Yellowstone Ecosystem" course. The hyper-enthusiastic course instructor, Dave Willey, took us to see this amazing ecosystem, using the wolf-elk relationship as a platform for understanding ecological connections. Dave knows a lot about wolves, and showed us plenty. We mainly observed the Slough Creek Pack, but we also saw one of the Druid Pack (the 'original' pack that was reintroduced to Yellowstone in the late 1990s). We also got to observe black bears, elk, bison, grizzly bears, coyotes, bighorn sheep, and a bunch of birds-of-prey.

One bear encounter is worth recounting here: We had hiked from the Lamar Valley out to Cache Creek, where rumor had it the Druid Pack had holed up. We spent the morning "glassing the slopes" (searching with binoculars), but didn't locate any of the wolves. No one had seen them in three days, and we were having the same luck. We began hiking back to the Lamar and our van. At one point, our group separated into two groups. I was at the tail end of the front group, and stopped to answer the call of nature before dropping down to the flat Lamar Valley floor. This short break to take a pee ended up preventing a major bear encounter, as it turned out. Why? It gave the front group time to get down ahead of me, so instead of staring at their backs, I was looking out over the valley. And there I saw two grizzlies heading through the sagebrush, on a direct line towards my colleagues! I called out to warn them (they couldn't see because they were on the same level as the bears, not elevated like I was). We all moved up onto the hill, so we could see the bears and the bears could see us. The tail end of our group caught up, and Dave shouted at them to get up to the high ground. Then we noticed another group of hikers, heading in on the trail. Through the binoculars, we could see that they were oblivious of the bears. We shouted to them too, and they moved up towards us. At that point, the lead bear huffed up and started galloping! "Oh shit," Dave said, "Who's got the bear spray?" When your wildlife ecology professor says "Oh shit," it's time to start worrying. Fortunately the bear's gallop lasted only twenty feet or so (a mock charge?) and then the pair resumed their amble through the sage. They crossed the trail a few feet from where the other group of hikers had been, and headed up a small wooded valley.

We all breathed a sigh of relief, and ventured down off the hill and onto the trail again, keeping a wary eye on the wooded valley. Safely past it, we relaxed and began hiking normally again, at which point we got a great look at a big black wolf trying to cross the Lamar River to our left! It was definitely the closest we had been to a wolf all week! The wolf got spooked by some fishermen, however, and retreated up the hillside on the other side of the road. Pretty cool stuff to see. The Yellowstone Ecosystem appears to be alive and well, even with wolves being "delisted" as threatened species in March, and then reinstated as "endangered" yesterday.

Also, while we were there, a man was attacked by a (probable) grizzly in his tent two campsites up the road. Pretty scary stuff, no longer being at the top of the food chain. These animals will eat you! For me, it was really insightful to get to experience some of that firsthand. This trip was the first time I had camped in the park (in spite of numerous visits over the years), and I really enjoyed the early morning and late evening wildlife viewing: that's the time to be out there!

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Sunday, July 13, 2008

Dinosaur paleontology of the Hell Creek Formation

Got back yesterday from six days out in eastern Montana, at Makoshika State Park. I was there on one of my four MSSE classes this summer, and I learned a lot. As many of you know, I'm trained as a structural geologist, not a sedimentologist. Though I use a lot of sedimentology (and fossils) in my Historical Geology course, there is much I have left to learn. Some of those gaps got filled in this week during "Dino Camp," though. Plus we had a lot of non-geologic fun!

The Hell Creek Formation is well exposed in Makoshika, as well as the overlying Fort Union Formation. The Hell Creek is latest Cretaceous, while the Fort Union is earliest Paleocene. The boundary formerly known as "K/T" is therefore between the two, and it records the changing of the eras: from Mesozoic to Cenozoic. I say "formerly known as K/T," since Tertiary is an archaic term that has been replaced (sort of) with Paleogene. The Paleocene is the first epoch in the Paleogene period. The sedimentologically-defined boundary between the two formations is the lowermost "significant" coal layer. We found this coal, the so-called "Z Coal," and you'd think that would be the K/Pg boundary, but it ain't that simple. True, there are dinosaurs below and no dinosaurs above, and it's also true that the Z Coal has been shown (rather shoddily, by the description we got) to have an iridium anomaly at its base. But there aren't any dinosaur fossils at all for 3 meters below the Z Coal, so the dinosaurs could have gone extinct well before the Z Coal was deposited (and before the iridium-rich clay layer was deposited). And of course, there's nothing in the deposition of a layer of coal that indicates it should be contemporaneous with a mass extinction -- it's just coal. Furthermore, the coal is lake coal, and the lake wasn't necessarily regionally extensive. It's a funny way of defining a critical geochronologic boundary: by the lowermost layer of lake coal in an area -- a criterion which could vary temporally from one place to another. Tricky business!

Anyhow, we prospected for dinosaur fossils. The course had two instructors, Jim Schmitt and Frankie Jackson. Frankie is a paleontologist, and she had a permit for collecting fossils on behalf of the Museum of the Rockies here in Bozeman. We found a lot of vertebrae, some five or six inches across. Plus, we found a bunch of leg bones, some rib fragments, and one of our team actually found the top of the frill on the back of a Triceratops skull! It was all pretty impressive.

In the evenings, we discussed scientific papers about field technique, the Hell Creek Formation, taphonomy, and the extinction of the dinosaurs. All our meals were cooked for us by Frankie's cool husband Bob, and so it was really ideal: Go out and learn all day, come back to camp to a hot meal, a cold beer, and a discussion of big picture ideas. My fellow teachers and I also played a lot of horseshoes and frisbee. To top it all off, when we got back to Bozeman yesterday, a group of us rented Jurassic Park and watched it over pizza and ale.

Next up: tomorrow I begin my Wildlife Ecology of Yellowstone course. Ought to be a similar high-octane experiential blast! More at the end of the week...

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Wednesday, June 18, 2008

The rest of the way

Sooo.... I've been "delinquent" about posting (if five days off counts as delinquent). But the long and the short of it is that I made it to Bozeman, and started classes, and have settled into life up here. After leaving Denver, I spent a couple days in Fort Collins, Colorado, staying with my undergaduate mentor professor Larry Wiseman. When I was at William and Mary, I forged a strong relationship with Larry, and that persisted even though I defected from biology (he's a developmental biologist, and chair emeritus of the department there) to geology (basically because they had more field trips). Anyhow, he and I would gather once a month or so for coffee and talk about life, the West, Ed Abbey, art, and science.

Now he's retired and pursuing bird rock art and also teaching cell biology at Colorado State University (in Fort Collins). We drove up to Rocky Mountain National Park and toured the various microbreweries and restaurants of Fort Collins (and Lyons). It was, in short, a good time.

Departing there on Saturday morning, I drove north through Wyoming, and camped at the end of the day at Buffalo Bill State Park, on the east flank of Yellowstone. On Sunday morning, I drove through the park, marvelling at six-foot-deep snow on Washburn Pass, and cruising along past tourists and bison galore. I stopped once, to look at the single petrified tree there, and then rocked and rolled on up the Paradise Valley to Livingston, and thence westward on the interstate to Bozeman.

In Bozeman, I'm enrolled in the Master of Science in Science Education program at Montana State University. It's essentially all science educators who are taking graduate coursework to become better science educators. And it's fun! This week, I'm taking Dave Lageson's class on the geology of the northern Rocky Mountains. More on that later, perhaps, but the point for now is that I'm enjoying it, and enjoying interacting with my fellow MSSE educators.

Tonight, I had a bonus, when we had a mini-conference of geobloggers. I guess there's somewhere around 50 geobloggers out there now, but we had four of them sitting at one table in Montana Ale Works, talking rocks and fossils and blogging and whatnot. That's got to be a record for the geoblogosphere. It was a lot of fun. Thanks to Mel, Brian, and Jeannette for making it happen!

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Sunday, May 18, 2008

Yellowstone photos

Today, some shots from my time in Yellowstone National Park last summer. Here's Mammoth Hot Springs:

Mammoth Hot Springs, Yellowstone National Park

Close-up of the travertine deposits at Mammoth:

Travertine deposits at Mammoth Hot Springs, Yellowstone

Me advertising my brother's company at Mammoth:

Advertising Connor's company at Mammoth Hot Springs, Yellowstone.

Norris Geyser Basin, slime:

Thermophile bacteria, Norris Geyser Basin

Norris Geyser Basin's loneliest tree:

Norris Geyser Basin's loneliest tree

More slime, this time two colors:

River of two colors of slime

Nasty patch of slime. Looks like snot:

Nasty looking patch of bacteria

Bison herd:

Buffalo

Columnar jointing in basalt:

Columnar basalt

Me showing you where the columnar jointing is. (I'm pointing at it...)

Me pointing out the columnar basalt.

Strata exposed in the Tower area:

Strata

And here they are again, labelled:

Tower area strata, labelled

Lastly, heading north out of Yellowstone back to I-90 and Bozeman, here's a weathered-out Eocene dike in the Paradise Valley. The dike is more resistant to weathering than the rock it cuts through, so it stands up as a "wall"-looking feature.

Eocene dike

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Thursday, January 24, 2008

Yellowstone, Newberry, & lithospheric thickeness

Last night at the year's first meeting of the Geological Society of Washington, Derek Schutt of the National Science Foundation gave a talk entitled "The Yellowstone hotspot and how it got that way." Derek mainly focused on the evidence for there indeed being a mantle plume under Yellowstone, possibly caused by the destabilization of the core-mantle boundary layer when subducted Farallon lithosphere sank down to the bottom of the mantle.

But the thing that he said that really caught my attention has to do with one of the weird aspects of Yellowstone. Yes, to the southwest of Yellowstone's modern caldera is the Snake River Plain, a series of ancient calderas which overlap one another, getting older and older the further to the southwest you travel, until you get to the oldest one at 17 Ma. That part of it looks pretty much like a classic hotspot track, a la Hawaii. But there's a weird aspect to Yellowstone that doesn't fit the traditional hotspot stereotype: starting at that same 17 Ma caldera/"rift," another series of eruptions propagated away to the west/northwest, including the voluminous Columbia River flood basalts and leading to the Newberry Caldera, which Derek described as "the largest basalt dome in the United States." (See the map above, from Schutt's collaborators Gene Humphreys and John Hernlund.)

So, the question is: What's up with that? It kind of looks like two hotspots heading in different directions. Is this linked to the stretching of the western U.S. via the Basin and Range? Derek pitched another idea, which is based on the thickness of the lithosphere (crust + uppermost mantle). His idea is summarized in the diagram below, which I drew this morning based on my rough sketch of the diagram he put up on the screen at GSW last night. (My apologies to Derek if I've gotten any of the details wrong.)



The basic idea is that the North American lithosphere is thicker to the east, under Yellowstone, which Derek (admittedly loosely) defined as the Wyoming Craton. He suggested that the lithosphere was thinner to the west under Newberry and the Columbia River Plateau, since those were accreted terranes added to North America during the Mesozoic. The mantle plume came up underneath the thicker lithosphere, and punched a hole through right above it (Yellowstone), but part of the plume slid upwards and westwards towards the thinner lithosphere, where it broke through in multiple locations, producing first the Columbia River flood basalts and then later the eruptions culminating in Newberry. I like the idea, and the picture Derek showed is elegant. I can picture this happening, if the suggested lithosphere thicknesses are true. The question is, are they? I don't know enough about that region of the country (yet) to assess the validity of this model. I wanted to use this blog post to share the notion, and see what people think. If you're familiar with that area, please clue me in to the details.

An additional difference between Yellowstone and Columbia River/Newberry (CR/N) is that Yellowstone's magma is rhyolitic and CR/N's magma is basaltic. Rhyolitic magma is a lot more explosive than basalt, and indeed Yellowstone's eruptions have been among the most powerful observed in the geologic record. (The Huckleberry Ridge tuff, which erupted from Yellowstone 2.1 Ma, is deposited over something like half of the Lower 48!) CR/N, on the other hand, appear to be gentler eruptions more like Hawaii's oozing of basalt. I suppose this too can be explained by Derek's model: partial melting of the more-felsic crust under Yellowstone (as hot plume magma heats that thicker slab of continental crust), but a shallower Moho to the west, producing mafic magma a shorter vertical distance from the surface.

PS -I must also add that it was great to meet Tuff Cookie of Magma Cum Laude at the meeting. If there had been one more of us there, it could almost have been a geology blogger's conference.

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