Researching Volcanoes and Other Geological Phenomena at the 'Center of the Earth'
In her laboratory, scientist Elizabeth "Liz" Cottrell uses sophisticated equipment to simulate the extreme conditions found deep below volcanoes – creating pressures equivalent to the center of the Earth and temperatures hotter than the sun. Her experiments at the micron scale are shedding light on the processes that have shaped our planet.
Liz is a geologist at the Smithsonian Institution's National Museum of Natural History where she directs its Global Volcanism Program as well as serving as a curator and research geologist in the Department of Mineral Sciences. Her research involves studying the geochemical composition and evolution of the deep Earth mantle and core, including how this impacts volcanic formation and eruptions.
Liz fell in love with the study of volcanoes while at Brown University, where as an undergraduate student, she explored the cataclysmic eruption of the Santorini volcano, Greece. After receiving her Bachelor's of Science degree in Geochemistry at Brown, she went on to receive her Ph.D. from Lamont-Doherty Earth Observatory at Columbia University where she studied the global magma ocean that scientists now believe enveloped the early Earth.
Her current research focuses on the evolution of the Earth, exploring a wide range of areas -- from the formation of the Earth's metal core 4.6 billion years ago to the ongoing modification of Earth's interior due to what she calls "biological contaminants." For these studies, Liz relies on samples brought to the surface by volcanoes and experiments she performs in her laboratory because, "despite what you may have seen in the movies, you can't visit the center of the Earth!" she says.
"We use volcanoes as a window," she says, to learn what is happening deep below volcanoes. In this regard, creating intense degrees of pressure on rock and crystallized samples that she studies from volcanoes and the Earth's mantle is key. "Pressure changes everything," she says.
One sophisticated laboratory machine she uses is called a piston cylinder which is capable of compressing and literally melting samples under up to 4 gigapascals of pressure (about four orders of magnitudes of pressure greater than what we are now under).
"From these studies we can generate the kinds of materials that can come out of volcanoes," says Liz. "And in doing so, we learn more about what's down in the interior of the Earth, how does it melt, how it make volcanoes, and how those materials interact with the atmosphere and create the world we see around us."
Her research delving into the planet's evolution took a major step forward recently when she, in collaboration with scientist Katherine Kelley of the University of Rhode Island, helped shed light on why the Earth's mantle is more oxidized at subduction zones – areas of the ocean floor where tectonic plates merge – than at mid-ocean ridges, where plates spread apart.
Commenting on the groundbreaking study, Liz says: "The availability of oxygen in the mantle controls everything from viscosity and the types of minerals found there to the kind of gasses that are being put into the atmosphere by volcanoes. This study helps us understand how the mantle and the Earth's surface interact and evolve over time."
In addition to her other research in geology, Liz, as director of the Smithsonian's Global Volcanism Program, also documents the eruptive histories for all known active volcanoes on the planet. The number of documented active volcanoes is around 1300, and about 20 are erupting at any given time, she says. "But if you count seafloor volcanoes," she adds, "the number of active volcanoes may be more than a million."
The public can keep track of active volcanoes (including the recent volcano Eyjafjallajökull in Iceland, which Liz studied) on her program's website http://www.volcano.si.edu/ .
And after the recent 9.0 magnitude earthquake and resulting tsunami disaster occurred in Japan in March 2011, Liz provided a clear and insightful scientific explanation to the public of how these events occurred.
Liz's geological research has been supported by the National Science Foundation, a Fulbright Scholarship, the American Association of University Women, the Department of Energy, and the Smithsonian Institution. She is the author of numerous professional articles which have appeared in such journals as Science, Earth and Planetary Science Letters, Geochimica et Cosmochimica Acta, and Geochemistry Geophysics Geosystems.
"The best part about my job is figuring how things work," says Liz, who advises young students to "study what interests you," and encourages girls not to forget that "you CAN be both a scientist and a mom" if they choose.
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