Two SIUC geologists were part of a scientific team that recently discovered an active, previously unknown volcano on the sea floor off the Antarctic Peninsula.

Associate professor Scott Ishman and graduate student Phillip Szymcek were among scientists from six U.S. and Canadian universities who verified the volcano's existence this past April. The National Science Foundation, which funded the research, formally announced the discovery in May.

The as-yet-unnamed volcano is in an area known as the Antarctic Sound, on the eastern side--and near the tip--of the peninsula (the continent's long, skinny arm). The volcano stands 2,300 feet above the sea floor; its top is roughly 900 feet beneath the ocean surface.

The volcano's significance is its youth. While there are historical accounts of volcanic eruptions on the western side of the Antarctic Peninsula, Ishman says, "all of the known volcanic rocks on the eastern side are at least two million years old or older. This volcano isn't related to those older rocks; it is a sign of renewed activity on the eastern side."

According to the NSF, the discovery explains historical reports from mariners of discolored water in the area, which can be caused by volcanic material.

The team used a bottom-scanning video recorder, rock dredges, and temperature probes to survey the sides and crest of the submarine peak. The probes revealed slight warming of the water, and the dredges recovered fresh, basaltic rocks--a clear sign of volcanic activity.

In addition, the video showed dark rock toward the top of the volcano that was devoid of sea life, another indication of very recent lava flows. "Some of the freshest rock we recovered may have been just a few months old," Ishman says.

Rather than having a central vent that gives rise to explosive lava flows, the volcano appears to release its lava through fissures similar to those of the shield volcanoes of Hawai'i, Ishman explains.

Further study will enable volcanologists to determine how deep the source of the magma is within the earth's mantle. That will help them reconstruct the evolution of the Antarctic Peninsula.

The discovery was serendipitous. The expedition team, led by Eugene Domack of Hamilton College, left April 16 from Chile to continue its investigations of Antarctica's Larsen Ice Shelf. Large sections of this ice shelf have disintegrated in the past decade, and the research team is studying the causes and nature of the breakup.

On this particular expedition, however, icy seas prevented the team's research vessel from reaching the Larsen area. The team decided instead to try to confirm the volcano's existence, whose presence was hinted at in sonar maps of the sea floor they had made during a January 2002 research trip.

Ishman and his students have been working to get a good picture of climate change in Antarctica since the last ice age, roughly 12,000 years ago. Their research, featured in the Fall 2002 issue of Perspectives, will help scientists determine the extent to which ice melting in Antarctica is due to global warming caused by humans or to natural climate cycles.

--by Pete Rosenbery, Media & Communication Resources; Marilyn Davis, ed.