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Chemists and biologists have a pretty easy time of it when claiming everyday relevance for their particular fields of interest. The evidence is everywhere, they say. Just look around.
For geologists, making their case seems to require more imagination on the part of the listener. The time scales are immense, the classic geological stand-in — the rock — is the epitome of stolidity, and geologic activity, when it occurs, is hardly predictable and usually far away.
Nevertheless, Woodside resident and San Francisco State University assistant geology professor Mary Leech picked geology for her career and hasn't looked back — an inapt figure of speech, perhaps, given that geologists tend to spend a lot of time looking back.
For her part, Ms. Leech, 37, is now notable for peering some 57 million years into the planet's past in dating activity on the Earth's crust that led to the birth of the Himalayan mountain range. The National Science Foundation recently awarded her $507,264, in part so she can continue her examination of mineral crystals from this region.
Her study of these ancient crystals has refined the estimate of the Himalayas' origin by as much as 11 million years from previous estimates based on the fossil record, she says.
Her five-year award, the Faculty Early Career Development Grant, is the NSF's "most prestigious award for faculty at the beginning of their careers," a university statement said, and one that "recognizes those who exemplify the role of teacher-scholar through outstanding research, excellent education and the integration of education and research."
Ms. Leech is married to Stanford University professor of geophysics Simon Klemperer. The couple have a daughter in kindergarten at Ormondale School in Portola Valley.
Elementary school, and her daughter's entry into it, inspired the other purpose for the NSF grant money: helping the next generation of science teachers, and familiarizing current teachers with earth sciences.
In September, Ms. Leech will initiate a program for graduate and undergraduate SFSU geology students with an interest in teaching to collaborate in creating geology lessons for San Francisco teachers in grades 3 through 6.
"Earth science is a good way of introducing kids to science because it's so interactive and hands-on," Ms. Leech says in an interview in her fifth-floor office at San Francisco State that, on a recent day, looked out on a rain-soaked campus.
Geology can be magnetic for kids. "There are really some very pretty rocks and minerals, colorful things (and) dinosaurs," she says. "When I meet a kid who's interested in geology, it's usually one of those things."
That said, elementary school teachers with the right background for teaching earth science are uncommon. Thus the collaboration, an idea she says she is borrowing from a similar program in SFSU's biology department.
Seventy to 80 million years ago, geologists say, a part of the Earth's crust — a tectonic plate — that contains the Indian subcontinent broke off from super-continent Pangaea, headed north for 20 million years, and collided with south Asia. In the collision, the Indian plate slipped under, subducted, the Asian plate, which led to the formation of the Himalayas.
Sandeep Singh, a geologist in India, knew of Ms. Leech's past work studying areas where tectonic plates meet and asked her if she'd analyze the crushed granite he'd collected along the Indus River near the southwest edge of the Tibetan Plateau — a natural suture point for the Indian and Asian plates, Ms. Leech says.
Finding granite that happened to contain within it the right type of zircon crystals "was really a matter of luck," she says.
The key was finding crystals that, because of the very high pressures and temperatures of the continental collision, had undergone new crystalline growth. New zircon crystals often contain trace amounts of uranium, which decays into lead at a known rate, a convenient tool for determining a crystal's age, Ms. Leech says.
The critical piece of equipment is the Sensitive High Resolution Ion MicroProbe (SHRIMP), operated by Stanford University and the U.S. Geological Survey. The device measures a crystal's uranium and lead content to determine its age to within a million years, Ms. Leech says.
The NSF grant money will allow her more research in the Himalayas. She was there in the summer of 2008 and plans to return for more collecting and mapping in the summers of 2009 and 2010, she says.
Tibet itself has been off-limits to non-Chinese researchers since the 2008 Olympics, and access to the region is difficult, she says, because it sits amid the borders of India, Pakistan, China and Nepal. "All I can do is cross my fingers and wait for that work."
Meanwhile, India continues to slide under Asia at about 2 inches per year, and the Himalayas continue to rise. But their rising may not be purely a function of the collision's momentum.
The monsoon rain that annually pummels the range erodes south-facing slopes. Ironically, that erosion may help the mountains grow. As surface rock falls away, the surface weighs less and rocks under pressure from below may be pushing in to raise the mountains.
The NSF grant funds her testing of a theory that the new material starts its journey south as molten rock under the Tibetan Plateau.
The molten rock, as the theory goes, becomes plastic, like putty, as it is squeezed south and upward by the northward moving Indian plate, Ms. Leech says. As the material approaches the sloping surface of the mountainside, it gradually cools and crystallizes into granite outcrops.
Despite wind, rain and ice erosion, Mount Everest and the surrounding mountains continue to rise. Will they ever stop? "I suppose, once you subduct all of India" beneath Asia, Ms. Leech says, laughingly. "That'll take a while though."
Indeed, the magma under the crust will be molten for tens of millions of years, she says.
Has she ever been confronted by someone citing the Biblical allegation that the Earth is 6,000 years old? "Luckily, I haven't yet," she says, somewhat flabbergasted at the question.
"There's just no science to support that," she adds, noting her work with the radiometric decay of uranium. A 6,000-year-old Earth "is simply not possible."
A North American heritage
Ms. Leech is a native of the Bay Area with a bachelor's degree in geology from San Jose State University and a doctorate in geology in 1999 from Stanford.
She studied at the University of London as an NSF International Research Fellow, returned to Stanford for post-doctoral work and lecturing at SFSU, and became an assistant professor at SFSU in 2005. Her teaching includes the study of rocks, volcanoes, minerals and geochemistry.
Ms. Leech, a member of the Cherokee Nation, drives a late model Corvette, painted a totem pole handed down to her from her Native American grandfather, learned to make beaded moccasins from a Tlingit elder while at Stanford, and was a starting catcher at the western region Little League softball world series in 1987 in Kalamazoo. Her daughter is following in her athletic footsteps.
Ms. Leech is also a gardener, a swimmer and a world traveler. She particularly likes the big-game parks in South Africa and the Kilauea volcano in Hawaii, where a cloud of steam once condensed around her, leaving her covered with lava particles as fine as fiberglass.
From 1995-98, Ms. Leech was an NSF graduate fellow, and recently received a grant to buy an electron microscope for her department, she says. Find this article at: