Montana State University

Volcano researchers drawn to Bering Sea island

October 23, 2006 -- By Evelyn Boswell, MSU News Service


Todd Feeley studies the cliffs of St. George Island from an Aleut fishing boat. (Photo courtesy of Todd Feeley).    High-Res Available

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Tel: (406) 994-4571
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Three soggy researchers from Montana State University joined 100 Aleuts, 500 caribou and millions of birds in the middle of the Bering Sea this year.

"You're constantly trying to be waterproof, but by the end of the day, water has penetrated to some depth," said Sandy Underwood, a doctoral student who normally studies Mount St. Helens, but endured fog, wind and rain to help Todd Feeley and Meagan DeRaps study St. George Island.

Feeley is a volcano expert and associate professor of geology. DeRaps is an undergraduate student who did so well in Feeley's igneous petrology class that she was allowed to join his study of the Pribilof Islands.

"It was a wonderful learning experience," she said. "I would never have learned so much from a textbook or class assignment."

The trio left Bozeman in July, then flew about 500 miles west of Alaska's mainland and landed on St. George Island. One of five main islands in the Pribilofs, St. George measures about five by 10 miles. An airport lies in the southwest, a town in the northeast, and one road connects them. The MSU researchers spent almost three weeks on the island, clambering across its knee-deep and waist-deep tundra and circling it in an Aleut fishing boat. They collected rock samples, mapped faults, photographed features and tried to match landmarks they saw from the inland with those they saw from sea. The inland is largely rolling with a few rocks interspersed. Some of the coastal cliffs rise as high as 1,000 feet.

"The Pribilof Islands are often referred to as the ‛Galapagos of the North' because there's so much diversity," added Feeley who traveled to St. Paul Island in 2005.

St. George and St. Paul lie about 45 miles apart and contain the world's largest marine mammal herd, one of the world's largest sea bird colonies, and the largest native Aleut populations, Feeley said. Both islands are volcanic, but their differences affected diversity and the settlement of humans, animals and birds.

St. Paul, for example, has broad, sloping shorelines that are more conducive to people and seals, Feeley explained. More than one million northern fur seals breed on the two islands, but most of them go to St. Paul whose last volcanic eruption occurred about 3,000 years ago. Approximately 750 Aleuts live on St. Paul.

St. George's cliffs are more welcoming to birds. Most of the three million sea birds that nest on the two islands live on St. George, whose last eruption occurred about 1 1/2 million years ago.

Feeley wants to determine the age and geo-chemistry of the rocks on the two islands. St. George, since it's older, gives a glimpse into how St. Paul will look in the future, he said. St. Paul, since it's newer, provides a peek into St. George's past. Feeley also wants to figure out why the middle of the Bering Sea has any volcanic activity at all.

"Most volcanism on earth is associated with areas that have tectonic plate boundaries," Feeley said. "Here, you are in the middle of the plate."

The search for an answer will take some time, Feeley said. He and DeRaps will be able to present two papers, however, at the December 2006 meeting of the American Geophysical Union in San Francisco. DeRaps's paper will compare the geochemistry of St. George and St. Paul. Feeley's paper will discuss xenoliths, rocks that are pieces of the earth's mantle. They arrived on the surface of St. George because of lava flows.

Feeley's study is funded by the National Science Foundation. DeRaps' involvement was funded by an NSF program called Research Experiences for Undergraduates.

Evelyn Boswell, (406) 994-5135 or evelynb@montana.edu