An international team of scientists working in the Antarctic Peninsula have mapped, sampled, and collected bottom video data that indicates a major volcano exists on the seafloor of the Antarctic continental shelf. Scientists, currently aboard the Antarctic Research and Supply Vessel L. M. Gould, announced their discovery from the ship on May 5 after carefully assembling all the available evidence for the existence and nature of the volcanic feature.
The yet-to-be-named volcano is unusual in that it exists on the continental shelf, in the vicinity of a deep glacial trough carved out by past glacial expansion across the seafloor surrounding the site. The volcano stands 700m above the seafloor, extends to within 275m of sea level, and contains at least 1.5 cubic km of volcanic rock. The volcano lies along a NW to SE running fracture zone in an area known as Antarctic Sound, at the northernmost tip of the Antarctic continent.
The presence of the volcano was first suggested by swath maps of the seafloor begun in January 2002 that indicated a large concentric and symmetrical feature that is clearly not overprinted by glacial scour, thus suggesting a young age for the volcano. But it was not until this April that scientists supported by the U.S. National Science Foundation were once again able to gain access to the region.
The group conducted a careful survey of the volcano that included a bottom scanning video recorder, rock dredges, and temperature surveys along the sides and crest of the submarine peak. The video survey revealed a surface that is heavily colonized by bottom organisms. This dense mat of benthic life is broken along the edges of the feature by barren patches of dark, black rock with some flow structures (ropy and bulbous surfaces). No encrusting organisms were seen on these surfaces indicating recent formation of the surface. Rock dredges recovered abundant, fresh, and angular, olivine, bearing basaltic rock; many pieces were vesicular. Such rock would normally alter and weather rapidly when exposed to seawater. Temperature measurements using a high sensitivity temperature probe were made continuously across the bottom of the volcano which revealed subtle, yet tell tale signs of geothermal heating of seawater. This was noticed especially near the edges of the feature where the freshest rock was observed. These observations along with historical reports from mariners of discolored water in the vicinity of the submerged peak, indicate that the volcano has been active recently and is likely an incipient feature.
Science team members include:
Dr. Eugene Domack (Chief Scientist), Hamilton College; Dr. Stefanie Brachfeld, Montclair State University; Dr. Scott Ishman, Southern Illinois University; Dr. Amy Levener, Colgate University; Dr. Gerd Krahmann, Lamont-Doherty Geological Observatory, Columbia University; Dr. Robert Gilbert, Queens University, Canada.
