Geological Society of America
The stunning backdrop of the Wasatch Mountains frames this annual gathering of all things geological. Alexandra Witze reports back from Salt Lake City.
Day 4: Mysterious landslide fire collects theories
On Monday, a geologist here presented details of a bizarre fire triggered by a landslide in California (see our story, 'Geologists tackle landslide fire mystery').
When I left the researcher at his poster, he was hoping for helpful suggestions from the community on the fire's cause. Well, we have had many letters to firstname.lastname@example.org with possible solutions, some of which are quoted here.
Dr Devin Sapsford, research associate at Cardiff University's School of Engineering writes:
Pyrite oxidation is a very likely explanation, Its likely that the topography of the pyritic slip material is exacerbating the problem.
As the oxidation of pyrite proceeds (the reaction is strongly exothermic) and the temperature rises the transport of oxygen into the material can change from diffusive flow to advection driven by convection through the pile, convection is a very effective gas transport mechanism, as a result far more oxygen would be 'pumped' through the material resulting a self-perpetuating cycle of increased temperatures (as observed), oxygen transport and increase pyrite reaction rates. The fact that the material looks like it sitting on a slope means that (unlike a flat-lying pile of pyritic material) the majority of the material will have oxygen pulled through it by convection and therefore almost all the pyrite present will be happily reacting away.
Wayne Dailey writes:
Without having a good chemical analysis of the soil... one can only guess. There is a product that I have used over the years that gets fairly hot by exposure to the air, which contains iron powder, charcoal, salt, sawdust, and vermiculite... similar to what may be present in the soil since it is mostly shale, with bits of pyrite crystals (FeS) and carbonaceous material (lots of trees).
This reaction tends to form hard nodules, so when the reaction stops and the area cools, maybe nodules may be discovered in the hot spots (it would be a sign). Here is the link to the product as an FYI (http://www.heatfactory.com/FAQs/faqs.html), possibly you have used it in cold weather as I have.
Larry Hayes writes:
This sounds nearly identical to underground fires that burn for years in the coal mining area of Ohio. I have also heard of similar fires in peat bogs.
I suspect that a past forest fire left a hot spot that burned down into a thin layer ( 6-10 inches ) of dried organic material 3-4 feet underground and it has continued to slowly burn/smoulder since then.
This long-term burn would also account for the landslide. As the thin organic layer burned off under a larger area it would leave a partial void and a layer of powdery ash that would eventually cause the top layer to collapse and slide.
The slide would stir up some of the hot spots and cause some surface fires.
I betcha a dollar I'm right :)
Well, my question would be, what caused the landslide in the first place? Your story said, no one saw the landslide happen. I would maybe postulate that it was a meteor impact that caused the landslide and the residual heat.
[Alex says: the scientists considered this briefly but there is no evidence of an impact.]
'Balt', from the University of New South Wales, writes:
You mention there's carbonaceous material in the soil. Many years ago I have read a report on subterranean coal layers oxidizing (burning) for many years and over extended areas. Given there's an accumulation of such material, all it takes is a lightning strike to set it on fire, if there are any oxidizing minerals present, it doesn't even need to be exposed to air to keep burning at a slow but steady pace, thus generating the heat you're measuring.
As far as a trigger is concerned, why rule out an anthropogenic cause? I don't know the specifics of the area, but a campfire could just as well have stood at the beginning of this? Additionally, the fact that the landslide incurred the first fire doesn't necessarily mean it started it, it could also just have exposed an area that has been on fire long before but now is close enough to the surface vegetation to ignite it.
Day 3: Getting out of the office
As any geologist will tell you, it's not a real conference unless there's a field trip involved. Today, two dozen adventurers journeyed to the frontier wilderness of the Great Salt Lake - on a comfortable boat tour that included a three-course hot lunch.
Before the salmon and after the key lime pie, Dave Naftz of the US Geological Survey explained to us why the lake is such a wonderfully unique place. Trapped between mountain ranges, it is the remains of the much-larger Lake Bonneville, which once covered most of the state of Utah. (You can see the relic shorelines of Lake Bonneville, and many other ancient lakes, etched in the surrounding mountainsides.)
Today, the lake's salty waters harbor brine shrimp, the basis of a thriving industry that harvests the creatures as food for farm-raised prawns. Migratory birds use the lake as an important stopping point on their way from Canada to points south. Human interventions, such as building a railroad causeway right across the lake, have created unique testing grounds for differences in salinity and circulation patterns in different regions.
Yet most Salt Lake City residents have yet to appreciate the unique beauty of the area. Aside from a few diehard environmentalists, most locals regard the lake as a stinky, salty wasteland. Even as our two-hour tour drew to a close, we had seen not a single other boat on the water - a sign that we, for all our pampering, were apparently more intrepid than most.
Day 2: The good old days
Can you name the author of the first paper in American vertebrate paleontology? Would you believe it was Thomas Jefferson, former American President and main author of the US Declaration of Independence?
Jefferson's polymath tendencies extended far beyond politics and into the realm of paleontology, says Stephen Rowland of the University of Nevada, Las Vegas. Jefferson was fascinated by the notion of ancient creatures roaming the landscape, though, like most experts of his time, he could not grasp the idea that many of these great animals had long since vanished for good.
In 1796, Jefferson had just been persuaded to run for the presidency - a race he would lose, making him vice-president to John Adams before achieving the presidency itself four years later. But even as he prepared for his unsuccessful run, Jefferson was also gearing up to assume leadership of the American Philosophical Society, one of America's first scientific societies.
For his first lecture to the group, Jefferson decided to describe some mysterious bones he had received in the mail. They consisted of several arm, foot and toe bones, recovered from a cave in West Virginia. Jefferson patched them together and named the creature Megalonyx, or 'great claw'. He was convinced it belonged to a huge lion, some three times more massive than African lions. In fact, he used Megalonyx to argue against the influential Comte de Buffon's theory that New World creatures were smaller, more degenerate versions of Old World animals.
Yet in a classic case of last-minute panic, Jefferson soon realized how wrong he was. Reading a journal article just days before he was to deliver his lecture, he recognized that Megalonyx looked much like the giant ground sloth Megatherium. Jefferson scrambled to change his lecture, playing down the lion interpretation in favor of the sloth. And he quietly dropped references that chastised Buffon.
In other words, Jefferson set an early precedent for how to deliver a scientific paper - do lots of work in advance, keep an open mind, and never, ever get in public fights before you know what you're talking about.
Day 2: Rock stars
Along with the scientific sessions at this meeting are plenty of suggestions for how to better teach geology to students of all ages. One approach, which has worked well in physics classes among others, may be to go Hollywood.
A small crowd filed into Ballroom J today to hear Dexter Perkins, of the University of North Dakota, elaborate. He has put together short clips of movies - famous or not - that deal with geological topics. He swears his students love them, and may even learn some science. But he notes it's not a way to learn the hardcore details of structural geology: "The geology scenes, we notice, are about two seconds long."
As you might expect, natural disasters feature prominently in geology movies. There's Volcano and Dante's Peak for those who love magma (or those who love Tommy Lee Jones and Pierce Brosnan). Steve Martin handles earthquakes deftly in L.A. Story, in which a fashionable luncheon crowd competes to see who can remain calmest in the face of a steadily increasing tremor.
Desert scenes fill another category, from The English Patient to Hidalgo. The Ten Commandments features some very impressive sand ripples, not to mention the parting of the Red Sea. For pure cliff scenery, check out action flicks like Vertical Limit or Mission Impossible II. And if you're looking for plot and acting with your movie, try the climatic Mount Rushmore scene in North by Northwest - and be sure to examine the granite as Cary Grant and Eva Marie Saint scramble over the giant faces.
Perkins closed his talk with a plea for more suggestions of geology in the movies, particularly examples of different rock types. He has no shortage of earthquakes or volcanoes, he says. "But you try to find a metamorphic rock somewhere..."
Day 1: Au naturel
The bad thing about a geology meeting is that there are no vast piles of freebies provided by the pharmaceutical industry (see our blog from the reproductive medicine meeting in Montreal). The good thing is that you can get plastic dinosaur eggs instead. Geologists are, in general, a joyously uninhibited bunch, with a keen sense of humour. I have seen one person today boasting a t-shirt reading "sex with a miner".
I always love geology meetings because everyone is just so ... natural. The dress code of choice is jeans, plaid flannel shirts and sandals. The crowd now milling around the Salt Palace Convention Center is earthy-looking and tanned. They remind me of why I decided to major in geology in college: given the choice between cramming for an exam or going hiking among the granite on Massachusetts' Cape Ann, I voted for the hiking. These people clearly did, too.
Day 1: Geoparks
There's a fair amount of attention at this meeting to 'geoheritage', the notion of conserving natural features of geological importance. The United Nations Educational, Scientific and Cultural Organization (UNESCO) has stepped up efforts in recent years by coordinating a system of 'world geoparks'. These are places that carry not only geological but also cultural, archaeological or other significance.
UNESCO's geoparks effort is headquartered in Beijing, and China has taken a significant lead in having its sites recognized. The country has 12 world geoparks and 85 national geological parks - many of which were designated just in the past year, says Stephen Robinson of St. Lawrence University in Canton, New York.
China's geoparks appear to be well-administered, he says. The spectacular Stone Forest in Yunnan Province welcomes more than 2 million visitors each year, despite an entrance fee of around US$10. The Three Gorges region of the Yangtze River boasts similarly dramatic scenery, and tourists may be keen to view it before the mammoth Three Gorges dam threatens to flood it by 2009.
Many times, earth science comes to popular attention only in the context of natural disasters, such as the Indian Ocean tsunami or the Hurricane Katrina tragedy. Geoparks remind us that earth forces don't always have to be destructive - they can be as inspirational as a fine art museum.
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