Scientists Discover Undersea Volcano Off Antarctica

Scientists working in the stormy and inhospitable waters off the Antarctic Peninsula have found what they believe is an active and previously unknown volcano on the sea bottom.

The international science team from the United States and Canada mapped and sampled the ocean floor and collected video and data that indicate a major volcano exists on the Antarctic ontinental shelf, they announced on May 5 in a dispatch from the research vessel Laurence M. Gould, which is operated by the National Science Foundation (NSF).

NSF is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of nearly $5.58 billion. NSF manages the U.S. Antarctic Program, which coordinates U.S. scientific research on the southernmost continent and in the Southern Ocean.

Evidence of the volcano came as an unintended bonus from a research plan to investigate why a massive ice sheet, known as the Larsen B, collapsed and broke up several years ago. Scientists hope to understand whether such a collapse is unique or part of a cycle that extends over hundreds of thousands of years.

Scientific evidence the team collected also corroborates mariners’ reports of discolored water in the area, which is consistent with an active volcano.

Eugene Domack, a researcher at Hamilton College in Clinton, New York and the expedition’s chief scientist, said the volcano stands 700 meters (2300 feet) above the seafloor and extends to within roughly 275 meters (900 feet) of the ocean surface.

He estimated that the volcanic cone contains at least 1.5 cubic kilometers (.36 cubic miles) of volcanic rock.

By comparison, Mount Erebus, a known active volcano on Ross Island near McMurdo Station, NSF’s main Antarctic research center, is approximately 3,800 meters (12,400 feet) above sea level.

Hawaii’s Mauna Loa, the largest volcano on Earth, rises approximately 4,100 meters (13,600 feet) above sea level. Mexico’s Cuexcomate volcano is considered to be the world’s smallest, standing 13 meters (43 feet) tall.

The research team comprised scientists from Hamilton College, Colgate University, the Lamont-Doherty Earth Observatory at Columbia University, Montclair State University in New Jersey, Southern Illinois University in Carbondale and Queens University in Canada.

Domack said the volcano lies in an area known as Antarctic Sound, at the northernmost tip of Antarctica.

He noted that there has been “no previous scientific record of active volcanoes in the region” where the new peak was discovered and that it is north of an existing boundary where volcanic activity is known to occur in the region.

The volcano, which has yet to be named, also is unusual, Domack said, in that it exists on the continental shelf, in the vicinity of a deep trough carved out by glaciers passing across the seafloor.

Sonar maps made of the seafloor during a research cruise in January 2002 first suggested that the volcano exists. The so called swath maps showed a large concentric and symmetrical feature on the ocean floor that had not been scoured by the advance and retreat of glaciers. The absence of glacial scours indicates the suspected volcano is fairly young in geologic terms.

But it was not until April of this year that scientists were once again able to venture into the region to examine the evidence further.

In addition to mapping, the research team used a bottomscanning video recorder, rock dredges, and temperature probes to survey the sides and crest of the submarine peak. The video survey revealed a surface that is heavily colonized by bottom-dwelling organisms.

But a dark mat of underwater life is broken along the edges of the volcano by barren patches of dark, black rock indicating that lava has flowed there. Because no life was found on these surfaces, the rock is believed to have formed fairly recently in geologic time.

Rock dredges recovered abundant, fresh, basalt, which normally would be rapidly acted upon and transformed by seawater but appeared unaffected.

Highly sensitive temperature probes moving continuously across the bottom of the volcano revealed signs of geothermal heating of seawater. The heating 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.

Domack said expects that there will interest among other scientists to return to the area and study the peak in more detail.

“None of us on this cruise,” he noted, “are experts in volcanoes.”