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Anita Grunder

Anita Grunder,
Geosciences

 
 
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Ground Truth



Anita Grunder reads the land like other people read newspapers. For her, every feature, every outcrop tells a story about how the Earth’s crust stretches, squeezes and sometimes explodes in episodes of volcanism. While her research has taken her to Alaska, Mexico, Chile and Eastern Oregon, it’s at the OSU geological field station in Mitchell or in a valley in the Cascades where she shares what she has learned with her students.

"I make it a point in all my classes to get students outside to look at the landscape," says the OSU geologist. "It’s amazing when we go to an outcrop, and I ask them what they see. At first, they think this is kind of stupid. They might say the rocks are dark. Or there is moss growing on it. Or the rocks are in big pieces or little pieces. But all of that is information. We all grow up with a lot of intuition about our world because we see it functioning every day. But we don’t really use it.

"I tell my students they should always be asking questions and using their knowledge to wonder."

Grunder remembers the excitement she felt as an undergrad at the University of California, Berkeley. In a field course taught by a graduate student, she walked the Berkeley hills and interpreted the landscape by making maps. Inspiration came in "going out there and seeing the landscape in a different way, asking questions of it — rather than being in it passively, being in it actively," she says.

Her questions run deep, literally. She wants to know how magma that is formed miles below the surface in the Earth’s mantle seeps and rises through the crust. The answers could lead to better understanding of earthquake and volcano risks. What controls, for example, the likelihood of new eruptions at Newberry crater or in what is called the Rattlesnake Tuff of Harney County?

Time is a crucial factor. In some cases, such as in Eastern Oregon, the trip to the surface seems to be relatively clean and fast. That’s because the basalts and pumice–forming eruptions known as rhyolites show little change from their sources. "They are at the compositional extremes of what the Earth produces. The basalts come straight from the mantle," says Grunder.

In other places, such as the Andes of northern Chile, volcanic rocks show signs of a longer, more tortuous trip. There has been what she calls "crustal feedback," evidence that parts of the crust melted into the rising magma, giving it a different chemical signature.

The mystery lies in what drives these processes. At present, Grunder says, there are competing hypotheses but no broad agreement among scientists.

In dating rocks in the OSU geochronology laboratory, Grunder’s work invariably takes her into the distant past. Last summer, she and a research team that includes OSU students began a National Science Foundation–funded project in Eastern Oregon, looking at rocks formed over the past 16 million years in a line from Bend to southwest Idaho. "I love the time factor," she says. "That is my favorite single thing about geology. The whole mind–bending notion of very long periods of time. We have such a tiny view of what the Earth is capable of doing."

Anita Grunderís Web site
Department of Geosciences
OSU Foundation
National Science Foundation