Monday, September 21, 2009

James Balog on TED

If you haven't seen this yet, please watch it. Nice work, Mr. Balog!


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Tuesday, April 14, 2009

Change of topic: Hoffman lecture

Paul Hoffman is speaking next Wednesday (April 22) at the Geological Society of Washington; I've just recieved word that his topic has changed from Snowball Earth to "The Pleistocene glacial controversy and the discovery of climate warming and crustal dynamics." I'm curious to see what Hoffman has to say about the 160-year old controversy as to whether there had been recent "Ice Ages," and how that relates to his currently-controversial ideas about the Snowball. Whatever he says, it's likely to be thought provoking.

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Thursday, February 26, 2009

Iliniza Norte, Ecuador

For the penultimate post in my Ecuador travel series, I hereby recount the story of climbing the mountain called Iliniza Norte (16,997 feet above sea level: the tallest peak I've ever summitted).

We began by driving up from the town of Chaupi, where we were staying at a hostel, to the trailhead above treeline in the paramo ecosystem...
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We had hoped for awesome weather, but as with our previous peak bagging in Ecuador, the clouds were here too, making a ceiling that we headed up into...
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Heading up into the clouds; the valley below fades away...
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...and we start to see snow.
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We went up a long, steep snowfield for probably two hours... It was frustrating going: take one step forward, slide two steps backward. The snow got thicker and thicker...

Eventually, when we got close to the summit, we got off the snowfield and onto some rocks. I was surprised to feel how my energy spiked at the prospect of rock-scrambling. The long slog up the snowfield was boring and repetitive, but this was totally engaging as a physical/mental workout. Here's Lily and Diego climbing up:

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At the summit, there's a steel cross with various doodads attached...
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This is the highest point above sea level I've ever experienced. When I stood on the summit, my head was above 17,000 feet in elevation!

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Silly video of the summit team making celebratory noises:


Then Diego said, "I think we go down now, because of thunders."

The guy knows his stuff: as soon as he had said this, we heard a ba-boom from off in the white clouds somewhere... Yikes. Okay, time to head down.

Descending the rocks:
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When we got to the snowfield, another peal of thunder sounded, and this one was louder than the first one. The snowfield, fortunately, made for easy going -- we essentially skied down it. It was pretty exciting... Flashes of lightning, booms of thunder (sometimes within a microsecond of one another), adrenaline pumping, running/sliding/skiing downhill as fast as we could.

We did not get hit by lightning.

After we got below cloud level (and into a valley where we felt a little less exposed to lightning strikes), we could see that the lower elevations had gotten some frozen precipitation too: a mix of snow and hail:

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When we got back to the vehicle, we found it covered in hail:
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Now for the adventure after the adventure: driving down a steep, twisting, muddy mountain road that's coated with hail and host to numerous roaring streams of runoff. It was almost as intense as descending the snowfield amid lightning bolts: the vehicle slid and knocked against a mud embankment at one point, and it was all seriously sketchy. Diego said he had never seen anything like it.

Here's some video of a raging torrent of meltwater/runoff flowing over a road surface that's decorated with white hailstones:



We did not crash the car.

Back safely at the hostel, we took hot showers and drank beer and congratulated ourselves for clearly being such daring adventurers. Whew... the next morning, we took our weary selves back to Quito.

One more Ecuador post to go... on lichens... stay tuned.

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Sunday, February 8, 2009

Recommendation: "Watermarks" by BLDGBLOG

Tuesday, February 3, 2009

Euhedral ice

Last month, when hiking Iliniza Norte, a 16,997' volcano in Ecuador, we got up near the summit and began scrambling over the rocks there. Conditions were cold and snowy, and I was pleased to see some beautiful ice formations in protected nooks in the rock. These crystals of ice had a gorgeous branching pattern...

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To show this branching pattern close up, here's Lily's gloved hand holding two such crystals (fused together). They look like squirrel tails!

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The backdrop of oxidized porphyritic andesite (hosting lichens) isn't bad either.

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Saturday, January 24, 2009

Earth's 10 most spectacular places

The International Year of Planet Earth may have declared a list of "the Earth's ten most spectacular places." At least that's what they're saying at the Discovery Channel's new Discovery Earth site, where they have a rundown of all ten (with photos). (No mention of it at the IYPE site, though: It may be that the Discovery Channel is just highlighting ten of the many, many U.N. World Heritage sites... their language is unclear as to who decided on these particular ten.)

Regardless, the photos will whet your appetite. With my visits in bold, they are:

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Wednesday, January 21, 2009

A hike in Rock Creek Park

The day before Inauguration, I decided to celebrate George Bush's last day in charge of my country by taking a walk in the woods. Okay... that wasn't really my motivation. I was just procrastinating writing up my Structural Geology labs for the coming semester. Anyhow, for one reason or another, I took a stroll in the woods.

I brought my rootin' tootin' new camera with me, and took a few photos. I've got four things to show you: (1) some differential weathering, (2) some kink banding, (3) some cool effects in frozen soil, and (4) a critter.

(1) To start, check out this close-up photo of a stone bridge where the Klingle Valley merges with the Rock Creek Valley:
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Several of the (local) stones used in the bridge are weathering at a faster rate than the mortar (cement) that holds them together. As a result of this differential erosion, the less-stable rocks are recessed into the face of the bridge:

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Here's another one, where you can see that not all minerals are equally stable at Earth surface conditions. The large central quartz augen stands out in high relief as the micaceous & feldspathic schist around it weathers away.

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Yet another: recessed about an inch into the bridge:

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That's not all I saw. I also re-discovered the location of some kink bands along the Rock Creek Park bike path:

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These kink bands are similar to the ones that Spring 2008 Honors student Victoria measured and analyzed in Broad Branch (also in Rock Creek Park), but these ones are in a different location, further south in the park.

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What's worth noting about these kink bands is that they overprint the regional foliation of these schistose rocks. In order to do that, the force that generated the foliation must have been coming from one direction (call it east-west), causing the mineral grains to line up at right-angles to that stress. That allignment is what we call foliation. Later, a new generation of deformation came in from a different direction (call it north-south, approximately parallel to the foliation), kinking the pre-existing foliation. For more on kink bands in DC, see my "DC rocks" page.

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(4) One of the disadvantages to hiking in Rock Creek Park in the winter is that it's pretty monochromatic. One of the advantages is that with all the leaves off the trees, it's a lot easier to see new stuff. It's great woodpecker-watching weather, for instance. I saw five woodpeckers of two species that day. Also, it makes it a lot easier to see where the trails are. I saw a new trail that I had never walked before, and so I decided to check it out. I'm glad I did. One thing that I saw that is pretty cool is this effect in frozen soil:

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When water freezes, it expands in volume by about 9%, and that shows up here as the upper layer of wet soil froze, it expanded in all directions, pulling away uniformly from two large cobbles of quartzite. It almost makes it look like the quartzite cobbles shrunk in their "sockets," but really it's the "sockets" that got larger.

(4) Lastly, I was doubly glad to have taken the new trail because it was a "road less travelled" kind of deal. I was the only one there. As I trod along, suddenly I heard a scampering noise. It was a critter! It ran up a little gully and then paused as still as a stump, looking at me:

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Can't see it? Try this zoomed-in shot:

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It's a red fox! Vulpes vulpes, one of two wild canids we have in Rock Creek Park. Pretty good sighting -- only the fourth time I've seen one here (and I spend a lot of time in this park). And every one of those times was in the winter. Again, it's having those clean leaf-less views that allows hikers to see stuff like this.

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Tuesday, January 20, 2009

The cold lab, and avalanches

Ed Adam's "cold lab" (which I toured this past summer as part of my "Examining Life in Extreme Environments" class at Montana State University) gets mention in an article in today's New York Times. They also profile some of Adams' experiments setting off avalanches at Bridger Bowl, in the Bridger Range north of Bozeman. Worth a read. Some cool photos, too.

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Thursday, January 1, 2009

Younger Dryas Impact Scenario

An article posted last hour on washingtonpost.com by Joel Achenbach examines an upcoming paper in Science that explores the idea of an impact triggering the Younger Dryas glacial advance as well as ending the Clovis culture and triggering the extinction of the Pleistocene megafauna. The evidence is nanodiamonds in sedimentary deposits from 12,900 years ago. Read the article, and wonder how Joel Achenbach finds out about this stuff a day before it's published. How does he get his hands on this article with enough time to compose a newspaper piece about it, but the rest of us have to wait until tomorrow to read the original paper?

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Saturday, August 30, 2008

Watching weather

"Should we talk about the weather?"
-"Pop Song '89," Green, R.E.M. (1988)

Here's a satellite image of the Caribbean from early Friday morning:



Gustav's still moving northwest through the Caribbean, and set to enter the Gulf of Mexico by about midnight tonight, or early tomorrow morning. As you may have heard, everyone's getting ready for the worst-case scenario. Louisiana governor Bobby Jindal has already declared a state of emergency, and President Bush gave him a similar federal declaration. I'll be watching this one pretty closely over the next few days.

Another phenomenon that's manifesting itself over the coming days and weeks is the melting of the Arctic sea ice pack. As Al Gore noted in his speech the other night, the worst case scenario for melting of this sea ice has the Arctic ocean ice free sometime late in the term of the next president (but that's a worst case scenario). Certainly, the trend over time is towards less and less of the Arctic frozen. I follow the fluctuation of sea ice area on the website The Cryosphere Today (University of Illinois), which provides satellite data, graphs, maps, and animations of the areal extent of polar sea ice. Here, for example, is a graph showing the area of the Arctic Ocean covered by sea ice over the past year:



Last year, of course, it hit a record low, and there's still a few weeks to go before it starts freezing up again (mid-to-late September is the time of the minimum). Open Mind did an excellent post examining the trend here, although the pattern is also observable on this long-term graph from Cryosphere Today. Here's another one, from the National Snow and Ice Data Center at the University of Colorado, that gives a half-century of context to the graph above:


In case DC-area folks didn't hear about it, there's also been some recent flooding in the southwest. (Geoblogospheroids will be well aware of it already, thanks to excellent coverage from Lee Allison at Arizona Geology.) I swam in that canyon this summer, just above the confluence with the Colorado River, and so this caught my attention more than an equivalent story would have about flooding someplace I hadn't been.

In addition to these larger-scale phenomena, there's a more local kind of weather I'm watching too: it's actually started raining in DC, for the first time since I got back on August 1! (A perplexed Achenblog on this odd situation). Time to bust out the umbrella.

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Thursday, August 28, 2008

Frost on Mauna Loa

Two weeks ago, my friend Lily took a hike up Mauna Loa. Lily teaches science at a middle school on the big island of Hawaii, and we became friends this summer at MSSE Dino Camp. I would think that living on the island of Hawaii would have some major disadvantages over time (my guess is that I'd get cabin fever living on an island), but you can also imagine that it would have some major advantages too.

In addition to live volcanic activity, surfing, exotic birds, and just general paradise-like conditions, add this to the list: climbing a tropical volcano to see giant frost crystals forming on top! Here's an image she took at sunrise, looking west over the summit caldera:

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Mauna Loa is the largest volcano on the planet Earth. Rising 5 kilometers from the Pacific seafloor to sea level, then an additional 4 kilometers to its summit, Mauna Loa has an estimated volume of 80,000 cubic kilometers! It's big.

Because it's so tall, the weather at the top is much colder than the tropical sultriness at the beachfront resorts. Lily and her hiking partner found this out when they camped out on top, and woke to find that overnight, giant crystals of frost had grown spike-like from the tops of the exposed cobbles and boulders of basalt. I don't have a sense of scale here, but I'm guessing these are a centimeter tall or so... Here's a close-up of the lower-left corner of the upper image:

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Pretty cool, eh? Literally. Maybe Hawaii has more variety than I had assumed. I think this calls for a field trip to investigate!

Thanks to Lil for sharing the photo!

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Thursday, May 15, 2008

800,000 years worth of bubbles

A bunch of articles in today's issue of Nature use precise measurements of the composition of glacial air bubbles to extend the record of atmospheric gases (and airborne dust) back to 800,000 years before present. (Previously, the record "only" went back to 650,000 years before present.) Fully eight glacial cycles are seen in the new, expanded dataset. These new findings are all part of the European Project for Ice Coring in Antarctica (EPICA), and they offer some new insights, as well as additional confirmation of the close link between climate and past fluctuations in CO2 and CH4. Check it out.

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Thursday, January 31, 2008

Baffin Island icecaps down 50% since 1958

A new study in Geophysical Research Letters uses C-14 to date the shrinkage of the ice cap on Baffin Island, in Canadian Nunavut. Baffin Island is the fifth largest island in the world, located just west of Greenland.

As the (non-flowing) ice cap withers, it exposes vegetation which has been buried beneath the ice since ancient times. This organic matter can be dated using the relative proportion of isotopes of radioactive carbon-14 and its daughter product, stable nitrogen-14. The oldest date found so far is apparently 350 AD.

The researchers, mostly from the University of Colorado at Boulder, also used measurements of cosmogenic ("made by space") nuclides in the rocks on which the ice cap sat to figure out how long they had been uncovered by the ice. I'm not an expert on cosmogenic nuclide exposure dating, but it works something like a sun tan: how long have the rocks been exposed to the barrage of radiation from the sun? If they've been exposed for a long time, they build up a substantial amount of these "cosmogenic nuclides" that wouldn't be found in an unexposed sample of the same rock. In my local area of mid-Atlantic North America, a study by Paul Bierman, et al. (2004) used cosmogenic berylium-10 to date bedrock terrace levels along Mather Gorge, thereby revealing the incision history of the Potomac River.

However, this is the first time I've heard of carbon-14 used as a cosmogenic nuclide. The authors offer this justification: "In situ cosmogenic radionuclide inventories in rock surfaces provide an integrated record of periods of ice-cover and exposure at a specific site since the end of the last ice age. We utilize in situ cosmogenic 14C due to its short half-life. In situ 14C production is reduced by 85% under 6 m of ice and is completely attenuated under 35 m of ice. Any 14C that had accumulated in rocks prior to the last glaciation would have decayed below our background after 25 ka beneath the Laurentide Ice Sheet." Is this coming from nitrogen in the rocks, the same way carbon-14 is generated in the atmosphere? Or is some other element/isotope serving as the source material which then gets changed upon exposure to the sun? Enlighten me if you know! It builds up specifically in quartz, if that helps at all.

Anyhow, they've found that half the ice cap has melted in the past 50 years. Half. Yep.

References:

Anderson, R. K., G. H. Miller, J. P. Briner, N. A. Lifton, and S. B. DeVogel (2008), A millennial perspective on Arctic warming from 14C in quartz and plants emerging from beneath ice caps, Geophys. Res. Lett., 35, L01502, doi:10.1029/2007GL032057.

Bierman, P., E. Zen, M. Pavich, and L. Reusser (2004). The Incision History of a Passive Margin River, the Potomac near Great Falls. USGS Circular 1264: Geology of the National Capital Region—Field Trip Guidebook, Trip #6.

University of Colorado at Boulder press release on the study.

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Sunday, January 27, 2008

Ice balls in a Michigan lake

My friend Casey went to Michigan last weekend to hang out with her sisters, and one thing they did was go snowshoeing/sledding at the YMCA camp where they all grew up. When they walked out to the lake, an interesting sight awaited them: a scum of ice balls floating in the water, and (presumably pushed by the wind), collected up along the shore. She brought back some photos.


It's a neat phenomenon, and I'm not really too sure what to make of it. The question is: are these concentrically zoned features, like oolites, hailstones, or the hematite concretions seen in Friday's post? Or are they fragments of lake ice that got broken up and then rounded due to abrasion and jostling against one another in the waves? I'm guessing that the first hypothesis is correct, but unfortunately I don't have any way to test it from here in DC.


Some observations: the ice balls are pretty well sorted, pretty spherical, and well rounded. The ice balls are packed closer together closer to the shore. There also seems to be a size gradient from larger ice balls close to shore (right, in the image below) to smaller ice balls out into the open water of the lake (left, in the image below). If this isn't just a trick of the camera's perspective, could this correspond to increased growth due to closer packing (and thus more time lifted up out of the water into the cold Michigan air) close to the shore?

Finally, I note that in some areas, multiple ice balls have clumped together into a larger entity, as some oolites will do. This cohesion between ice balls is potentially the first step for making a solid layer of ice that will extend out from the shore over the whole lake.

Anyone else ever seen anything like this? What's going on?

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