Written by Kenneth W W Sims.
In 1841 James Clark Ross and crew in two tiny ships “Erebus” and “Terror” discovered Ross Island. They named the highest peaks after their ships and quickly recognized their volcanic origin. Erebus was in a state of vigorous eruptions at the time. Later in the early 1900’s British explorers explored parts of the island and found it was completely volcanic and composed of solidified lavas and associated deposits from explosive eruptions.
Ross Island is now home to the U.S. Antarctic Program’s McMurdo Station, Antarctica’s largest research base. Erebus volcano is the world’s southernmost active volcano and is the 18th largest in the world based on volume. It is both awe-inspiring and threatening to the inhabitants of McMurdo Station (1000 people in the summer and ~180 in the winter) as its summit (12,448 ft elevation/volume 2170 km3) and persistent gas plume dominates their northern skyline (Plate 1).
Although there have now been over 40 years of scientific expeditions to study Erebus volcano, geologic studies of Ross Island’s other volcanic centers – Mt. Terror (3262 m, 1700 km3), Mt. Bird (1800 m, 470 km3) and Hut Point Peninsula (100 km3) – are remarkably sparse and outdated. As a consequence, our knowledge of the geological origin of the Ross Island volcanoes is incomplete.
Using funding from the National Science Foundation (NSF), we are conducting a field and laboratory based study to examine the hypothesis that volcanism on Ross Island is the surface expression of a deep mantle upwelling in the form of a mantle plume or hot-spot (Plate 2). This aspect of our research is timely in that recent “geophysical observations” indicate that the mantle beneath Ross Island is hotter than its surroundings.
Our study will also provide a critical contextual perspective for the well-studied and iconic Erebus volcano. While Erebus is the only currently active volcano on Ross Island, understanding past volcanism on Ross Island’s other volcanoes (Mt. Terror, Mt. Bird and Hut Point Peninsula) is essential to predicting future volcanic activity, both at Erebus volcano and elsewhere on Ross Island. The key to predicting a volcano’s future is understanding its past.
During the field portion of the study (Oct 22-Nov 28, 2012), our team will be collecting about 60 samples from the summits and flanks of Mt. Terror, Mt. Bird and Hut Point Peninsula on Ross Island. This effort will involve using helicopters and snowmobiles to circumnavigate Ross Island to collect lava samples from the sea cliffs along the ice edge, as well as using helicopters to go to the summits of Mt. Terror and Mt. Bird to collect samples from exposed lava flows and vents (see Plate 3). We will also be camping for several days on the flanks of Mt. Erebus on “Fang Ridge” to collect samples from its ancient eruptions and also on the coastline at Cape Bird penguin rookery.
For the laboratory based portion of the study we will be measuring the geochemical properties of the lava samples back in the US at our state-of-the-art laboratories at the University of Wyoming, New Mexico Institute of Mining and Technology, University of Oregon, Arizona State University and Woods Hole Oceanographic Institution. These new data combined with our previous research on the Erebus volcano, will provide essential information on the nature of the mantle source beneath Ross Island and the causes of its volcanism, both past and present.
Ken Sims is an associate professor at the University of Wyoming, the PI on the NSF grant funding this research. This will be Ken’s 10th season in Antarctica (eight as a mountain guide and two as a PI on scientific grants). http://geology.uwyo.edu/kenwwsims
Philip Kyle is a professor at New Mexico Institute of Mining and Technology, co-PI on the NSF grant. This will be Phil’s fortieth season! in Antarctica. http://www.ees.nmt.edu/kyle/
Paul Wallace is a professor at the University of Oregon, collaborating scientist. This is Paul’s first season in Antarctica. http://pages.uoregon.edu/pwallace/index.html
Glenn Gaetani is an associate scientist at the Woods Hole Oceanographic Institution, collaborating scientist. This is Glenn’s first season in Antarctica. http://www.whoi.edu/profile/ggaetani/
Erin Phillips Writer is a PhD student working with Ken Sims at the University of Wyoming. This is Erin’s first season in Antarctica. http://geoweb.uwyo.edu/ggstudent/ephilli8/Site/Welcome.html
Dan Rasmussen is an MSc student working with Phil Kyle at NMT. He was an undergraduate student at the University of Oregon where he did a senior thesis with Paul Wallace as his adviser. This is Dan’s first season in Antarctica.