I really enjoyed Freakonomics, and so it was disappointing to hear that the recently-released sequel, Superfreakonomics, had a section devoted to the suggestion that global warming was going to be imposssible to solve via cutting carbon emissions (with renewable energy sources) and so we should focus our efforts on geoengineering schemes instead. RealClimate has a well-written post up today showing just how sloppy the Superfreakonomics authors' thinking on this issue is.

Labels: books, climate change, global warming, politics, tech

On the day before the GSA meeting began, I participated in a field trip to the Boring Volcanic Field, a zone of anomalously-located volcanic vents around Portland, Oregon. The field is named for the Boring Hills, adjacent to the town of Boring, Oregon, which is named for a dude named "Boring." Kim Kastens noted this funny name on the Earth and Mind blog recently. The USGS maintains an information page on the field here.

Today, some photos...

Atop Rocky Butte, field trip leaders Rick Conrey (WSU) and Russ Evarts (USGS Menlo Park) orient the group with a map highlighting the various units comprising the Boring Volcanic Field:


Mount Hood hides its peak in the clouds:


At our first outcrop stop, the field trip participants get out and look at the Boring rocks:


Here, a Boring lava flow overlies Troutdale Formation fluvial gravels:


Annotated version for the untrained eye:


In places, a "baked" zone of contact metamorphism can be seen in the Troutdale as it got scorched by the lava that flowed on top of it (bright red), but the characteristic red color was missing underneath one spot, the central overhang in this photo:

Weird, huh? Maybe the metamorphosed sediments need a certain amount of rain-mediated chemical weathering before they "blush"?

Well-rounded clast from the Troutdale: vesicular basalt from the Columbia River Plateau:


Another nice Columbia River flood basalt boulder, this one with phenocrysts of plagioclase, and a concentric zonation of texture (massive in the center, vesicular towards the edges):


Plus, you can find cobbles derived from further afield: gneiss (from Idaho?), quartzite (Belt rock?), etc:


Between cobbles of the Troutdale, you can see hyaloclastic sand (immature sand with lots of hydrated basaltic glass fragments, apparently produced by interactions of magma and water in the source area, upstream):


More hyaloclastic sand:


Oooh! A "crack panel" on the side of some cooling columns at another stop! These horizontal slats are produced in individual fracture-propagation events, and each one concludes with a little ridge called an arrest line.


Mafic pyroclastics that underlie the lava flows at this second stop:


More mafic pyroclastics, on a cinder cone in Mount Tabor Park.


This is a pretty neat outcrop: you can see normal faults cutting these angle-of-repose inclined volcanic strata, presumably forming in slumping events.


Annotated version of this same photo, highlighting a marker layer and its offset along the fault:


The weather was pretty grim for this trip, so that was a bummer. But it's Portland, right? What did we really expect? Anyhow, I enjoyed being introduced to this suite of rocks -- boring out of context, but interesting given their location well west of the main axis of Cascade volcanism. Unfortunately, the field trip didn't really address why the Boring rocks are there. I was expecting some sort of detailed discussion of the possibilities: an evaluation of different models for their generation and passage to the surface... but that really didn't happen in any substantive way. So it wasn't the most amazing field trip I've ever gone on, but it was a nice day of checking out a cool suite of rocks.

Labels: meetings, oregon, pleistocene, pliocene, sediment, volcano

On his popular science blog Pharyngula, PZ Meyers has a regular series of posts called "I get email," (example) wherein he discusses e-mails he gets. I get e-mail, too (as I'm sure, so do other science bloggers of all stripes). Here's one I got the other day from Brian, a recent graduate from one of my many almae matres (oh yeah, I took Latin). I post it here in case anyone else is wondering the same thing:

I have a simple question for you... I was out at the Pimmit Run-Potomac
confluence collecting rock samples with that awesome chlorite/pyrite/garnet
assemblage and I encountered a couple pieces of unakite float. I'm just
wondering about its provenance. Your blogs seem to indicate that unakite is
typically found in situ farther west in the Shenandoah which would be a pretty
long way to travel (and pretty cool too!) although I believe there is Antietam
around Mather Gorge so I guess it's not impossible; unless it was
anthropogenically relocated which would be much less cool. A little insight
would be greatly appreciated so I can wow my friends when describing what is now the piece de resistance in my fish tank.

So I wrote back with this (links are additions, since I'm blogging it):

Yes, you could certainly have found some Blue Ridge unakite as float in the Potomac Gorge. I've seen many other Blue Ridge Formations as float on the bedrock terraces of the Potomac: Catoctin Formation, Harpers, Weverton, Antietam (like you mentioned), and something that looks a hell of a lot like the Old Rag Granite. I've found well-rounded bituminous coal cobbles, too! I've found unakite further out, in the Coastal Plain, as well as blue quartz (which is unique to the Blue Ridge). So I think it's quite likely you could have found some unakite.

Anyone else have any questions? Like PZ, I could make this a regular series. The more local and the more geo-centric, the better.

Labels: blue ridge, coastal plain, i-get-mail, metamorphism, piedmont, rivers, sediment

It's the Earth's "birthday!" Today, October 23, is the anniversary of the 4004, BCE creation of the cosmos, according to Archbishop James Ussher, Primate of All Ireland and Archbishop of Armagh. Ussher is famous for having made a pre-geology attempt to date our planet using a literal interpretation of Biblical scripture and a carefull tallying of "begats." Though a scholarly and noble attempt given the intellectual context of his day, Ussher's ideas were soon supplanted with the discovery of deep time by geological studies, starting ~100 years later with another James, James Hutton. The accepted age of the Earth was pushed back further and further by subsequent geological work, and our currently accepted age for the planet (and the Solar System) is approximately 4.6 billion years. Despite these insights, there are a substantial number of "Young Earth" creationists who stick to Ussher's number, or a similarly itty-bitty age derived from a Holy Book of their choosing. This bizarre contention puts them in the awkward position of having to deny the fossil record, the decay of radioactive isotopes, the expansion of the universe, and (of course!) the evolution of species by mechanisms other than Special Creation by a diety. Because Ussher was a scholar and a thinker as well as a religious man, my suspicion is that if he were alive today, he would reject the close-minded anti-science that so many creationists voice.

I love the fact that Ussher's title was "Primate," considering that the main issue creationists have with evolution is that they don't want to be descended from non-humans. The word primate comes from the Latin for "first" (as in "primary") and reflects Ussher's position at the top of the Church of Ireland, and Linnaeus' view that the primates were "first" among the mammals, an anthropocentric bias that persists in uncountable ways today. The truth of the matter is that humans are primates, and so are baboons, lemurs, gorillas, and yes, even chimpanzees.

Ussher was indeed a primate -- just like the rest of us. Happy birthday!

Labels: geologic time, history, words

Here's a photo of 18 of the 19 geobloggers who assembled on Monday night in Portland:



I had to do some photoshopping, as you might have deduced. Not everybody was in the same place at the same time: herding geobloggers is worse than herding cats! So... I've had to be creative to get them all in the same jpg space.

In alphabetical order, those pictured are:

• Andrew Alden, About.com
• Jessica Ball, Magma Cum Laude
• Callan Bentley, NOVA Geoblog
• "Silver Fox," Looking for Detachment
• Steve Gough, Riparian Rap
• Anne Jefferson, Highly Allochthonous
• Kim Hannula, All My Faults Are Stress Related
• Kyle House, Geologic Froth(ings)
• Erik Klemetti, Eruptions
• Jim Lehane (younger of the two Jims), Dino Jim's Musings
• Chuck Magee, Lounge of the Lab Lemming
• Marcella, Pooh's Thoughts
• Mary, a geo-Twitterer
• Jim Repka (older of the two Jims), Active Margin
• Brian Romans, Clastic Detritus
• Ron Schott, Ron Schott's Geology Home Companion Blog
• Peter Selkin, Oblate Spheroid
• David Williams, Stories In Stone

MAK was there too, but for some reason I don't have him in any of my photos... Sorry!

Labels: blogs, meetings, oregon

Great graphic by Nate Burgess in a recent EARTH, and now just posted online. I especially like the column, and the punch-line ("proposed cross-cutting relationship"). Brilliant!

Labels: art, humor, stratigraphy

My final day at GSA was fruitful. I started off in the "Earth, et al." session hosted by ODU's Nora Noffke. It was devoted to the Precambrian, and had some interesting talks about fluctuating oxygen levels, mineral evolution, microbially-induced sedimentary structures, and Neoproterozoic glaciation. This last one was most interesting to me: UMD's Jay Kaufman talked about field work he conducted in Siberia last summer, documenting a diamictite unit between Ediacaran strata and Cambrian strata. There's even a carbon isotope excursion to match up with it! Cool... literally.

I had lunch with my friend David Dantzler, who I hadn't even realized was at the conference, until I saw him come in to one of the Darwin-focused sessions. In the afternoon, I attended another eight talks, including some on greenstone belts in South Africa, some on geological education, and a couple about the evolution of orogens, with an emphasis on South America. (One of these was an excellent talk by Brian Romans about his field area in Patagonia.) I finished up with Kim Hannula's talk about the geoblogosphere's role in supporting women geoscientists. Then it was time to bug out: back to the hotel, then to the airport, then to Los Angeles, then to Dulles, where I arrived this morning at 6:30am. On the flight, I took an Advil PM, put in earplugs and wore one of those little eye-masks so I could get some decent amount of sleep... Mixed success on that front. Once I got to Dulles, I got some coffee, and headed straight to work! It's good to be back in the familiar environs of my office and lab again. Thanks for a great conference, everyone!

Also: GSA is maintaining a webpage summarizing the various posts from registered geobloggers. It's incomplete, but a useful idea: a repository for all the stuff being said about the conference from the various attending geobloggers.

Labels: archean, blogs, geology, hadean, meetings, oregon, patagonia, proterozoic, snowball earth

Whew! A busy day at the Geological Society of America meeting in Portland, Oregon. I started off the day in the two-year-college session, culminating (for me, anyhow) in my talk about the role that field trips play in my geology classes at NOVA. I believe in spirited presentations, so I moved away from the lecturn and spoke extemporaneously about my images and data, and the talk was well-received by the audience -- or at least that portion that chose to tell me what they thought. After the talk, I was really tired out (I hadn't realized I was stressing about the talk, but apparently I must have been.) I went back to the hotel and took a shower, dealt with some mortgage stuff (I'm buying a condo in DC), and then semi-refreshed, headed back to the fray at the Convention Center.

I've met another several geobloggers: Brian Romans and Kim Hannula. Geoblogger Lockwood Dewitt sent me a rock (natrolite in calcite! likely from a pillow basalt!) via roaming geoblogger "Silver Fox." Cool. I dig it. I had some people come up to me out of the blue and tell me that they read this blog, and that is super cool to hear. Thanks!

In the afternoon, I went to a few sessions about volcanism and the end-Permian extinction, history-of-geology, and I forget what else.

In the late afternoon, the beer began flowing. I started off at the W.W. Norton publishing company's beer bash, where I brushed shoulders with Walter Alvarez, met the author of my Physical Geology textbook, Steve Marshak, and chatted at length with Bob Lillie of Oregon State University about getting the National Park Service better educated about their geological resources. Then it was off to the AGI reception, where I won a bottle of wine and got to chat with David Williams, author of Stories In Stone. Meg Sever, the editor of EARTH, with whom I've e-mailed a zillion times, but never met. Turns out Meg went to William & Mary, like me (and Jessica Ball, also at the AGI reception), so the three of us trooped upstairs to the William & Mary alumni reception. It was good to see Brent Owens, Heather McDonald, and Chuck Bailey there, as well as other W&M geology grads (including Graham, who reads this blog! Hi Graham!).

The evening's final event was the much-ballyhooed geoblogger's meet-up. At 8pm, about fifteen of us assembled at Tugboat Brewing Company, a cozy, charming little pub in downtown Portland. Every time someone walked through the door, a rousing, "Yeeeaaaahhh!!!" cheer went up. And every time someone left, they got booed! It was terrific fun meeting everyone that I've had these online geoblogging relationships with over the past ~1.5 years, and I think a good time was had by all. I'll put some photos up later... [Other online reminiscences about the meetup: Chuck and Jessica.]

Labels: books, geology, meetings, national parks, nova, oregon

It's been a year since an attempt I made to characterize the geoblogosphere via an online survey, and two weeks since I asked you geobloggers to take the survey that geobloggers Lutz Geissler and Robert Huber put together. I reviewed a rough draft of their survey and made some suggestions. My biggest suggestion of all, though, is aimed at you: Please complete the survey!

It will be open through the end of this month, and after all the data is in, Lutz and Robert will chew on it, and eventually we'll disseminate our findings.

So... Please take the survey. Thanks!

Labels: blogs

The Sunday afternoon sessions were not as diverse for me as the morning sessions, but there was some fun stuff in there.

I started off with the "digital advances" session co-sponsored by geobloggers Kyle House and Ron Schott. Working with several other organizers, Ron and Kyle put on quite a show. Kyle gave his "Get with it, Luddites!" spiel, Ian Jackson evangelized about OneGeology (a global geologic map), geoblogger Lee Allison talked about geoblogging and geotweeting (and featured the blog title banners of several GSA-attending geobloggers, including mine), and Declan De Paor (from Virginia's own Old Dominion University) showed off many of the myriad very cool digital techniques he is using. He began his talk by putting his iPhone number up on the screen and then encouraging the audience to text him their questions as he spoke, so he could read them off the iPhone propped there on the lecturn and answer them as a seamless part of his talk. Then Ron demonstrated a virtual field trip that integrated Google Earth with Giganpan imagery. When it worked, this really awed the crowd. Unfortunately, Google Earth crashed repeatedly during the demo -- which must have been frustrating for Ron. Then the talks stopped an the informal demonstrations and playing around with the technologies began on the edges of the room. Milling around in the crowd, I met for the first time fellow geobloggers Jim Repka and "Silver Fox," and chatted a bit with Kyle and Lee.

(I should also mention that I ran into Bryan of In Terra Veritas and Andrew Alden earlier in the day: geobloggers galore!)

Then I went to see Bob Hazen talk about how mineral surfaces could have provided a template for organizing biomolecules as a prelude to the origins of life. It was cool, but more of an overview talk rather than a presentation of new research.

I went to a couple of very well-attended but lackluster presentations on Sierran uplift, and then closed out the day in the structural geology session, which included an interesting study about detrital zircon populations presenting skewed age populations if the basin from which they were derived had experienced landslides. Finally, Doug Burbank of UCSB gave an invited lecture and the feedbacks between geomorphology, climate, and mountain building. I checked out a few dozen posters, and then called it a day.

Labels: geology, meetings, oregon

The Annual meeting of the Geological Society of America is underway!

I enjoyed a nice field trip yesterday, investigating some anomalous igneous rocks around Portland; more on that in a later (illustrated) post.

Last night, I had dinner at the Deschutes Brewpub with Michelle Arsenault of NSF, volcanological blogger Erik Klemetti and his wife, and a fan of NOVA Geoblog, Dennis M. This was a fun and eclectic group of people, with all sorts of unexpected connections! And the Obsidian Stout was lovely...

Today the meeting proper began, and I have been delighted to attend talks on topics as diverse as geoscience education, the 1959 Hebgen Lake earthquake, biomarkers (chemical "fossils"), uplift of the Teton range, oxidation of the shallow ocean before the "Great Oxidation Event," and the recently-much-hullabalooed plumbing system beneath a Permian "supervolcano" in Italy. Wow! Such interesting topics, such skilled speakers, such inspiring scientists. I heard one geologist tell firsthand about his experiences living through the Hebgen Lake quake, and another put forward the suggestion that Ediacaran fossils are lichens, not animals. Several workers presented evidence that there was a substantial land biota in the Neoproterozoic. When ideas like that are being batted around, it's hard not to catch the excitement. More later... Now it's time for me to head off for another round of talks!

Labels: geology, meetings, oregon

Last night on my flight from DC to Portland, there were five GSW members ... About one-twelfth of the population of Wednesday's meeting! Plus I ran into the geologist from Blue Ridge Community College and a grad student from Virginia Tech. Cool!

Labels: gsw, meetings, oregon

A while ago, I offered some thoughts on podcasts I've been listening to. Here's a few more I've discovered since then (and that I like):

Sixty-second science - From Scientific American comes this podcast which is, as the name suggests, about science and also very, very short. Each episode is about one minute and eleven seconds, when you tack on the introduction and the the conclusion -- but the scientific content is top notch and enjoyably written. I dig it! A

RadioLab - kind of funky, disharmonic, self-indulgent production, but sometimes it really, really works. I really enjoyed the recent episodes about blinking and parasites. A-

Science podcast - From Science magazine comes a podcast to compete with the Nature podcast. The two are different: While they have in common interviews with scientists publishing groundbreaking research in the two respective journals, Nature's podcast is goofy, well-produced, and fun. Science's podcast is kind of stodgy and stiff by comparison. B-

Skeptic's Guide to the Universe - From the New England Skeptical Society comes this hour-plus-long podcast on science news and exposing pseudo-science for the bull$#@& that it is. I really like the format, although it must be said none of the five regular panelists are geologists, and they occasionally get stuff wrong like when the Cambrian was, or whether there is bauxite on the moon. Still, some great insights and perspectives. Thanks very much to Bryan for recommending this one to me: it has enriched my commute immeasurably! A

Labels: podcasts and vodcasts

I'm in the office this morning, taking care of a bunch of last minute details before I depart this afternoon for the Geological Society of America's annual meeting. It's held this year in Portland, Oregon, and I'm pleased to be going in spite of the many responsibilities I'm temporarily putting on hold back here in DC and NOVA. Meetings like this are a great opportunity for professional scientists to catch up on the latest ideas both inside and outside their specialties. I'm also going to be participating in a field trip to the awesomely-named Boring Volcanic Field tomorrow, and maybe doing a little self-guided tour of Portland's geology on my own. I will be presenting a paper of my own (on the role field trips play in geology education*) on Monday. I'm looking forward to meeting many of my fellow geology bloggers Monday night, and not looking forward to the red-eye flight back to DC Tuesday night/Wednesday morning... and then going straight back to work. Fortunately I think I've got all my stuff set for next week, so it should be "plug and play" upon my return... but I've got a hunch I'm going to be pretty tired, regardless.

So... take a deep breath, Bentley... here we go!
______________________________________
* subject of my MSSE capstone research project.

Labels: meetings, oregon, travel

Here's a sample I collected along the road in the Sierra foothills when I was in California the weekend before last. It's a nice little hand sample of amygdules: vesicles (lava degassing bubbles) that have gotten infilled with mineral deposits. I just slapped it on the scanner along with a penny. Enjoy!

Labels: igneous, primary structures, volcano

I've just submitted a list of the classes I intend to teach for summer 2010. Here they are on NOVA Geoblog, before you can access them in the official Schedule of Classes...

GOL 135 (070N) The Bedrock Geology of Washington, DC. HYBRID COURSE: pre-trip reading, field study and post-trip report. One-day field trip Saturday, June 12. Rain date: Sunday, June 13. Important pre-trip logistical information and preparatory readings located online. This trip will focus on the land upon which the capital city is built, including exposures in Rock Creek Park, Georgetown, and Adams-Morgan. Includes discussion of oceanic sediments, the Rock Creek shear zone, igneous rocks emplaced during Appalachian mountain-building, Cretaceous river gravels, dinosaur bones and recent faulting. Students will be evaluated with a field trip report which will be completed after the trip itself. NOTE: This trip involves moderately strenuous hiking on forest trails. Meet in back of the CT building at 9:00 a.m.; Return by 7:00 p.m. For information about meeting time/place or other questions call (703) 323-3276 or email cbentley@nvcc.edu
HYBRID course
Additional info online

GOL 295 (4 credits) Regional Field Geology of the Northern Rocky Mountains: July 10 to July 25, 2009. Pre-trip meetings Wed. June 9 and Wed. June 23, 6:30pm, in CS 217. Western Montana and Wyoming showcase tectonic, sedimentary, geomorphic, and volcanic features which provide world-class examples of geologic processes. Students in this course will complete field studies of locations in Yellowstone and Glacier National Parks, as well as several other field sites. The course will involve VERY STRENUOUS outdoor physical activity: Students are expected to hike several miles at high elevations in rough mountainous terrain in order to accomplish course objectives. Airfare, lodging, and transportation are covered in the approx. $1400 course fee (does NOT include tuition). For up-to-date information and a complete itinerary, see the course website or contact the instructor at cbentley@nvcc.edu or (703) 323-3276.
Extra fee
Instructor permission required
Additional info online

GOL 299 (071N) (2 credits) Snowball Earth. June 14-19, 2009. HYBRID COURSE: pre-course reading, lab, field study and post-course report. An episode of glaciation 700 million years ago, dubbed Snowball Earth, may have provided for the evolution of multicellular life. The Snowball Earth glaciations stretch our conception of the limits of climate change: the ice apparently reached from the Earth's poles to its equator! Scientists infer that the runaway freezing event was only ended due to volcano-induced global warming. This course examines the geological, chemical, and biological evidence for Snowball Earth, and includes a field trip to local "Snowball" deposits. Course meets four times: three evening sessions (6pm-9pm) in CS 217 and all day on a Saturday (9am-5pm). The schedule is: Monday June 14 (lecture), Wednesday June 16 (lab), Friday June 18 (discussion), and Saturday June 19 (field trip). For further information call (703) 323-3276 or email cbentley@nvcc.edu or go to the course website.
HYBRID course
Additional info online

Anyone in the Northern Virginia area who's interested in any of these classes, drop me a line!

Labels: dc, field trips, geology, montana, nova, snowball earth, teaching

Every two years, the U.S. Department of Energy sponsors a competition called the solar decathalon on the National Mall in Washington, DC. Teams from universities around the country and across the world design low-cost, low-emissions, low-energy-use, architecturally pleasing homes, then bring them to the Mall to assemble them. For two consecutive weekends, folks like you and me can go and tour the innovative shelters. It's really an inspiring experience, and quite popular for that reason.

Here's some photos from last weekend. If you're in the DC area, the homes are open again this Thursday (tomorrow) through Sunday. You should check it out.

Labels: dc, energy, environmental, sun

So that's how it works... (from the Onion.)

Labels: birdies, evolution, humor

Steve Fetter, former dean of public policy at the University of Maryland, came to NOVA to speak at our first annual Climate Change Symposium in 2008. He was our "headliner" act. Now, I learn from the University of Maryland alumni magazine Terp that Steve is now an assistant director in the White House's Office of Science and Technology Policy. Congratulations Steve!

Labels: climate change, maryland, meetings, politics

NOVA's accurately-named student newspaper, Fortnightly, is now online. New issues every fortnight (two weeks)!

Labels: news, nova

Returning now to some of the stuff I saw when I was out in Bishop, California for the GSA Field Forum I attended in September. One of the cool little spots we visited was "the flipping fault," a location on the Volcanic Tableland north of Bishop where an east-dipping fault scarp dies out and a west-dipping fault scarp starts up. Check it out:


Here, try one with annotations:


Here's a Google Map of the location, as seen from the perspective of a passing turkey vulture:

Notice how the road, Casa Diablo Road, goes right through the notch where the two meet. Complicating the picture a wee bit is a Pleistocene drainage channel which uses the same route between the two scarps (and diverges from the road in the lower-left).

Another view, further back and higher up:


And of course we must annotate that one too:


Recall that these are normal faults busting through the Bishop Tuff's upper welded layer, the "Ig2." In the annotations, I've sketched in the approximate position of the "hanging-wall cutoff" (lower boundary of each scarp) and the "foot-wall cutoff" (upper boundary of each scarp).

There are roughly equal numbers of east-dipping and west-dipping faults on the Volcanic Tableland. Originally, some creative structural geologists wanted to interpret this feature as an overall "propeller" shaped fracture: a so-called "flipping" fault (as in, it's one single fault that flips its dip direction in the middle). However, this was not the interpretation of our workshop leaders, who suggested that it was simply two faults that started independently and then propagated towards one another.

Taking a fresh look at these images now, almost a month after I visited the outcrop, I find that I agree with them. One thing that seems obvious to me now is how the east-dipping fault truncates on the face of the west-dipping fault scarp. My annotations reflect this interpretation. What do you think?

Labels: california, conferences, meetings, structure

Another amazing image from NASA's Earth Observatory. This one shows the smoke plume that resulted from the "Arnica Fire" in Yellowstone National Park. Pretty impressive shot...

Labels: national parks, wildfire, wyoming, yellowstone

Got a computer but don't use it 24/7? Perhaps you might consider lending some of its processing power to modeling climate. The more computing power, the more robust the models' predictions can be. More information here: essentially download a program that makes use of your computer's computing power when you're not already using it for other stuff, like Facebook.

Labels: climate change, tech

In case anyone has not been following the thread at the old post on this topic, here's the plan for geology bloggers who want to meet up and quaff some ale at the GSA meeting in Portland the week after next: let's meet up 8pm at Tugboat (link to map) on Monday night, October 19.

If anyone is around on Friday Saturday, I'll also be at the Deschutes Brewery (link to map) on Friday night, October 16, at 8:30pm: A fan of NOVA Geoblog invited me out for a beer! (Why don't the rest of you do that?) You're welcome to join us: The more, the merrier.

Saturday night and Sunday night are wide open for me. Give a shout if you want to make a plan.

Labels: blogs, meetings, oregon

First I've seen of last week's tsunami. Attempt to embed below, but here's a direct link.


Hat tip to my student Al for passing this on. Thanks Al!

Labels: earthquakes, news, tsunami

Heh heh heh.

Labels: action, climate change, global warming, humor

As noted earlier, I had the good fortune to spend last week in Yosemite National Park, celebrating the wedding of my friends Jason and Lindsay, and in general poking around in one of the coolest places around. Below, a summary of the three-day trip:

Friday:
Lily and I flew to Modesto, California, and rented a car. It took about two hours to drive up to Evergreen Lodge, where we checked in and then headed out for a short hike in the Hetch Hetchy area. Hetch Hetchy was dubbed "Yosemite's sister valley" by John Muir in an attempt to keep it from being dammed. But the city of San Francisco had been destroyed in 1906 by earthquake-induced fire, and the call for a reliable water source was an important force in overpowering Muir's conservationist ideals. Ken Burns apparently explores this saga, the first instance of "development vs. conservation," in the second episode of his new National Parks series. (I saw the first episode, but haven't caught up on the rest of it yet.) The valley was dammed in the 1920's, creating the Hetch Hetchy Reservoir:


Here's the O'Shaughnessy Dam, named after the chief engineer of the project:


I didn't find it as spectacular as Yosemite, but it was sure a pretty place. Walking along the north side of the reservoir, I reaquanited myself with some fine Sierran granites and granodiorites. Here's a sweet little xenolith (or maybe an MME; how can you tell an MME from a mafic xenolith?):

Back to the Evergreen for the rehearsal dinner (Oktoberfest theme!) and then bed.

Saturday:
Up early, got some coffee, drove an hour to reach the Yosemite Valley. I liked how quiet things were compared to the throbbing pulse of summer. This view of El Capitan, for instance, is typically mobbed with tourists. This day, we had it to ourselves for five minutes or so, then shared it with one other car:


Time to stretch the legs! We decided to hike up to Vernal Falls. On our way up, the base of the falls was still in shadow, with low-angle morning sunlight dramatically illuminating the upper reaches of the falls:


Looking back down the valley we had climbed up... I like the dark shadow of the cliff merging with the dark shadows of the trees below:


But if we set the camera's F-stop a bit differently, we can see what's going on in all that shadow. There's the trail we climbed up, with fellow hikers for scale:


Up top, photographing the waterfall:


On our way back down, with more of the falls illuminated as the sun rises in the sky:


Looking north across the valley from where we parked our car, marvelling at the huge exfoliation joints there: rounding these exposed plutons into granite 'domes.'


... or Half Domes, as the case may be:


A view from further out, again with Half Dome the most striking landform:


Then, we headed back to clean up before the wedding. Great ceremony, amazing meal. Drinks, dancing, rhubarb jam, bluegrass, reminiscing with old friends and new. Ahhh.

Sunday:
Breakfast and coffee with the wedding party, then off to check out some big trees. We drove to the Tuolumne Grove of giant sequoias. It started snowing on the way there, but we didn't let that deter us. On the hike down from the parking area (where, by the way, they had closed the Tioga Road), we found this nice example of spheroidal weathering in an outcrop of granite:


But the real attraction was the enormous sequoia trees. Here's one:


And a dead one, with a car-sized hole cut through it:


I found these trees very impressive: they were just stunning in their grandeur and immense age. Snow continued to fall as we left. We had to get going to make our flight home. Somewhere on the way down the mountain, Garry Hayes and his wife passed us going up the mountain. Ships passing in the night -- sorry I missed you, Garry! We made a couple of roadside outcrop stops, then got back to Modesto and traded in the car for an airplane. Our "redeye" route back to DC took us through San Francisco and Los Angeles, and I ran into Thomas Friedman in the airport. Got back to BWI at 6am, and headed off to work...

Labels: california, glacial landforms, national parks, plants, travel, tv, water resources, xenoliths

Friday, October 23, 2009, CE Forum
12 noon - 1pm

"Community-Based Environmental Action"

Chris Bright, President and Co-Founder of the Earth Sangha, a non-profit environmental group

The Earth Sangha is a Buddhist environmental group based in Fairfax County co-founded by Chris and his wife, Lisa Bright, to work with volunteers on ecologically significant restoration projects in natural areas. Every year over 500 volunteers donate more than 10,000 hours of their time to the Sangha's restoration projects throughout northern Virginia. Volunteers have built the Sangha's Wild Plant Nursery, DC region's most comprehensive local-ecotype native-plant propagation center. (Local ecotypes are local, wild native-plant populations; the use of local ecotypes is a standard best practice in restoration because that helps to conserve the genetic diversity and local adaptation in the species planted.) The Earth Sangha is also a kind of low-tech innovator in the control of invasive alien plants; such plants are a major threat to local natural areas. In 2006, the Sangha transplanted a version of its community-nursery approach to the Caribbean island of Hispaniola. The Sangha's Tree Bank / Hispaniola program works along a portion of the Dominican Republic - Haiti border, where it helps impoverished farmers improve their incomes and restore patches of native forest on their lands.

Chris Bright will describe the Earth Sangha's work, the rationale behind it, and its implications for the conservation agenda. Before founding the Earth Sangha, Chris was a Senior Researcher at the Worldwatch Institute, a think tank that tracks global environmental and social trends. He is the author of numerous articles and one book, Life Out of Bounds: Bioinvasion in a Borderless World, the first global, interdisciplinary study of biological invasion written for a general audience.

Labels: action, environmental, meetings, nova

"Heresy at Cambridge: Paleomagnetism before Vine and Matthews"

Gregory A. Good, Ph.D.
Director, Center for History of Physics
American Institute of Physics

Potomac Geophysical Society Meeting, October 15, 2009

The story of Fred Vine, Drummond Matthews, and sea-floor spreading is a well known part of the acceptance of plate tectonics in the 1960s. Vine and Matthews published their famous paper "Magnetic Anomalies over Oceanic Ridges" in Nature in 1963, but interest in paleomagnetism and continental drift in England started to rise as early as 1950 among a group of physicists and cosmologists there. These interlopers in geology -- Patrick Blackett, Teddy Bullard, and Keith Runcorn -- all had started in particle physics and cosmic ray research. How they ended up providing a basis for discovery in earth science traces an interesting tale of interdisciplinary research in the mid-20th century.

Greg is a historian of science who currently writes mostly about the history of geophysics and especially the history of geomagnetic research. He has degrees in both physics and in history of science and he taught in the History Department at West Virginia University from 1983 until 2008. He has been on the History Committee of the AGU since 1989 and is a member of GSA, the International Commission for the History of the Geological Sciences, and the History of Science Society. He has published many articles and two books, one on the geosciences at the Carnegie Institution of Washington and the other an encyclopedia of the history of the earth sciences. He edited the journal Earth Sciences History for the History of the Earth Sciences Society for six years. He was named a Fellow of the GSA this year, having received the Mary C. Rabbitt Award of the GSA Historical Division in 2008.

More information at the PGS website.

Labels: magnetism, meetings, pgs, plate tectonics

Today I took a group of students to Sideling Hill, a syncline in western Maryland. Here are a few photos from the trip. All photos by my iPhone, via Facebook (which is why the quality is lower than my usual standards):

The group all kitted out at the Sideling Hill Visitor's Center (which was closed due to budget cuts in Maryland):


Jared points out fast-weathering shale layers betwixt slower-weathering sandstone layers:


Diamictite outcrop on the far western side of Sideling Hill:


More diamictite... enigmatic sediments...

Labels: maryland, nova, primary structures, sediment, structure, teaching, valley and ridge, weathering

It's been a year since an attempt I made to characterize the geoblogosphere via an online survey. Now, geobloggers Lutz Geissler and Robert Huber have initiated a new effort at describing what's going on where geology and blogging meet. I reviewed a rough draft of their survey and made some suggestions, and was added on as a third investigator. The idea is that the survey will be open through the end of this month, and after all the data is in, Lutz and Robert will chew on it, and eventually we'll disseminate our findings. Schedule permitting, I'll present the results at the fall AGU meeting in San Francisco.

So... Please take the survey.

Thanks!

Labels: blogs, geology

My friends Jason and Lindsay had the good sense to get married in Yosemite this past weekend. So I enjoyed visiting the park, including some new places I hadn't been before, as well as the nuptial festivities. More later...

Labels: california, glacial landforms, national parks

"Earth and Mind," by the folks at SERC.

Labels: blogs, geology, teaching

Richard Dawkins is on a speaking tour in promotion of his new book on the evidence for evolution, which I just got yesterday. He's not coming to DC, but the closest speeches he'll be giving are in Charlottesville, at UVA (Oct.16), and then in Philadelphia, at the library (Oct.22).

Labels: evolution, meetings, pennsylvania, virginia

After yesterday's post on a new feature I found on the USGS earthquakes site, reader Tony Edger asks, "After exploring the USGS website and elsewhere without much success, I am hoping you might steer me to a description of how to read a seismicity cross section. " He was referring to these images:

So here's how this works: the top image is a map. It gives you a "bird's eye" perspective on earthquake locations at the subduction zone near Samoa. It shows you the epicenters (location on the earth's surface above a quake's actual location, called its "focus" or "hypocenter") of many earthquakes, along with Tuesday's big quake, shown with a star. The thick red line is the position of the trench, a bathymetric expression of the subduction zone. The epicenters are color-coded for their depth. Orange and yellow are shallow; green and blue are medium depth; and purple and red are the deepest. Notice that they make a sort of "rainbow" pattern, with the shallowest quakes in the east, and the deepest quakes in the west. This is "looking down" on the subducting slab: it's like we're able to "see" the subducting slab as it descends into the mantle.

The lower image is the cross-section. It gives you a "gopher's eye" perspective on the same data. A cross section is drawn along the line A-A' on the map. This is conceptually slicing the Earth open along that line, then removing half, and looking sideways at the remaining half. Note that the A-A' line is now along the top of the figure, representing the surface of the earth. Along the horizontal axis is horizontal distance, measured in kilometers. Along the vertical axis is depth, also measured in kilometers. The two axes are not drawn to exactly the same scale, but pretty close. In other words, 100 km of horizontal distance is approximately equal to 100 km of vertical distance (depth). The same data are plotted, or at least the subset of the map's data which happen to fall on that particular line, A-A'.

With this new perspective, a side-view, what do we see? Well, there's the star, which shows the depth of the quake that triggered all this discussion, and a whole bunch of other (historical) earthquakes. Now, instead of the epicenter being plotted, we're getting a more robust sense of the hypocenter (or focus). Note that the earthquakes are being generated in a big swath, starting at the surface in the northeast, and dipping down deeper and deeper to the southwest. This line of seismic activity reflects the jerking passage of the subducted slab of oceanic lithosphere. As it plunges down, it generates lots of shaking. This zone of seismicity was first described (independently) by two scientists, Kiyoo Wadati and Hugo Benioff: in their honor, it is referred to as the Wadati-Benioff zone. (Wikipedia has more) Their realization is our gain: we can "see" the subducted plate diving at an angle of 30 to 40 degrees. That's what's so cool about this:

Something that no human will ever directly observe is "visible" to us because we can pinpoint the three-dimensional location of thousands of earthquakes. These bumps and jolts reveal the position of the bumper and jolter: the subducting plate!

Labels: analogies, art, earthquakes, plate tectonics, websites

Kim makes an elegant pitch for a bunch of cool projects on DonorsChoose.org. Wow! There's so much cool stuff up there. If you have ten extra bucks, please go send it to a needy Earth science teacher so they can get their students excited about geology. Thanks!

Labels: action, teaching