Andrew's Geology Blog

The Earth Science Literacy Initiative makes my ears prick up—its goal is a consensus document on the "the big ideas and supporting concepts essential for an earth system literate public." This week the folks at www.earthscienceliteracy.org have posted a working draft of the eight big ideas, each with nine supporting concepts. Feed your mind and feed back your comments during the rest of October.

The U.S. Geological Survey has a long and distinguished history, but one lasting blemish on its record was the "reduction in force" or RIF of 1995, when more than one-third of its work force was laid off. A peculiarly large proportion of those laid off were senior scientists. Allegations of age discrimination arose immediately. As I recall, one employee who began collecting and discussing evidence was unexpectedly promoted into a position in which he could no longer speak out. Eventually people went to court, and three weeks ago the 9th US Circuit Court of Appeals ruled for James Calzia and Chet Wrucke. Wrangling continues, but this landmark was reported in the San Francisco Chronicle, and a commenter added links to court documents. Apologies for those readers who consider this old news, but for many others the memories are fresh, and the damage to the agency's collegiality was lasting.

Next month the 2008 Nobel Prize winners will be announced, and thanks to Alfred Nobel the honorees will include physicists, medical researchers and chemists but not geoscientists. I've gotten over that, really I have, because there are other prestigious prizes for them. But the wound is fresh when it comes to the annual Ig Nobel prizes, awarded by the Annals of Improbable Research or AIG. This year's winners have just been announced, and they include such worthies as the researchers who determined that slime molds can solve puzzles, but surely geologists have produced absurd and obvious research during the past year. I . . . just can't think of any.

One place that geologists would fit in beautifully is the AIG's Luxuriant Flowing Hair Club for Scientists; indeed, last week's MacArthur genius, David Montgomery, should be in it. They include beards, too, making large numbers of historic and current geologists eligible.

I was poking around the hills in my city the other day, investigating a sandstone. A few steps beyond the edge of the sandstone, the roadside showed no rocks whatever, just loose soil. But eventually I found a hard pod—a concretion—and pounded it open to find pure clay powder inside. That's how I knew the hillside was shale. Shale is what clay becomes when you bury it deep enough, and shale is usually eager to turn back into clay. This picture of shale is from a roadcut, and after only a few years in the sun and rain it would crumble at a touch. Shale wants to hide. That's why roadcuts are so important for getting fresh samples, even of reluctant rocks like shale.

Shale — Geology Guide photo

This is an apocalyptic week, especially on Wall Street. The hundreds of billions of dollars people talk about make me feel like I've been transported to Zimbabwe. I suppose a quick jolt in the stock market could make money evaporate at the rate of a billion dollars a minute. Imagine that!

Geologists can imagine much worse. In my own neighborhood of Oakland, California, a repeat of the 1868 earthquake on the Hayward fault will cause a couple hundred billion in damage in about a minute. A talk I'm seeing tonight—a close look at that quake—will probably turn my hair white; if not, the earthquake itself surely will. And the dreaded next great subduction quake in Cascadia, and the dreaded next great quake in Southern California, would undoubtedly rival it.

But last year I heard seismologist Ross Stein lay out an even direr scenario: a repeat of the 1923 Kanto earthquake, in the Tokyo region, would cost roughly a trillion dollars, something like $250 billion a minute. With its ensuing financial ripples, that would be a global catastrophe, a different order of event from this week's gyrations in virtual money.

This year's MacArthur Foundations Fellows were announced a few days ago, and geoscientist David Montgomery is richly deserving of his big cash grant. I learned long ago to read any paper that comes out with his name on it. He's been a leader in the line of research that ties continental erosion to plate tectonics. He discovered colossal glacial floods in the Himalaya. And he wrote two excellent books, one on the relationship of the salmon to recent geological history and the other on the crucial role of soil in sustainable civilization. Everybody likes him (for instance his local journalists at the Seattle P-I), and he could play himself credibly in a movie.

As a geomorphologist, David works in a tantalizing area of geology that reads the landscape itself as a record of the recent geologic past. Humans are sensitive to landscape by instinct—knowing where to look for water and friendly habitat is a crucial life skill that we have practiced in every setting on Earth, not just the African locales where the Homo genus originated. David enters this ancient, haunted terrain with a fresh eye and novel, testable ideas.

To close this entry the best thing I can do is point you to his article last year in GSA Today, "Is agriculture eroding civilization's foundation?" which summarizes much of his book Dirt: The Erosion of Civilization for an audience of his fellow scientists.

The latest Accretionary Wedge geo-blog carnival is a sprightly affair devoted to Earth science that's not on Earth. I was too busy doing other stuff to take part, but I have some existing material on Earth science in space—read more about solar studies, space radioisotopes, planetology, length-of-day research, atmospheric geophysics, satellite observations and cosmic impacts. (I wish I'd called it Spaaaace!)

When they get metamorphosed, high-aluminum rocks, like your typical shale and slate, tend to grow Al₂SiO₅. That may form one of three minerals, or polymorphs, depending on the temperature and pressure. Kyanite is the high-pressure, low-temperature form. This rock-shop specimen is cleaner and bluer than your typical occurrence, but not by much. See it and learn more in the Mineral Picture Gallery.
Kyanite — Geology Guide photo

Why do the islands of Tonga have huge boulders of coral sitting there on land? The first thing you might think is that they must have arisen when sea level was higher, like examples in the Caribbean. But Matthew Hornbach (Univ. Texas Inst. Geophysics) looked more closely at them and determined that they must have washed up there.

For one thing, the corals in these boulders are tipped, even overturned. Nor did the boulders have pedestals of limestone underneath them. This example, on Tongatapu island, rests on volcanic soil. Something carried them ashore; in geologic terms, they are erratics. No ordinary wave could have lifted this house-sized stone. But the area has unusually thin soil, as if it had been washed away recently, and the reef offshore appears to have chunks ripped out of it. And just 30 kilometers away is a chain of undersea volcanoes.

Hornbach noted that the great Krakatoa eruption of 1883 threw large coral builders ashore, like this example. The simplest explanation for the Tonga boulders, then, is that eruptions pushed large tsunamis toward Tonga which left these blocks on land.

Tsunamis don't arise only from earthquakes; landslides, eruptions and cosmic impacts create them too. Studying tsunami erratics, here and elsewhere, could yield important data on tsunami occurrence and hazards from this underappreciated source. This research is being presented next month in Houston at the Geological Society of America annual meeting, just one of many fascinating presentations.

Tongatapu and Krakatoa erratics — Photos courtesy Matthew Hornbach

Canada has always had a reputation for ancient rocks, but the September 26 Science puts a new jewel in Canada's crown in a paper reporting a bedrock outcrop that dates back to approximately 4.28 billion years, well into the Hadean eon (or, for purists, the Eoarchean Era). The previous oldest known rock, from about 4.03 Ga, was the Acasta gneiss, also Canadian.

The locality is in the Nuvvuagittuq greenstone belt by Porpoise Cove, way up by the north tip of Labrador on Hudson Bay. This photo, by coauthor Don Francis of McGill University, shows the look of the countryside there, scraped clean and flat by generations of glaciers. It's a geologist's dreamland. The Saskatoon StarPhoenix reports that the local Inuit tribe that oversees the site is pondering its potential for tourism. I know I'd go see it.

Shake sits in the Nuvvuagittuq — Courtesy Don Francis