Antarctic Expedition to Erebus Volcano Examines a Lake of Lava - Erebus page 2
|Thanksgiving dinner at the Observatory in 2002. Photo by Rich Esser|
|Bill McIntosh works on a wind-power generating station on the Erebus plateau in 2002. Photo by Dawn Sweeney|
|Dawn Sweeney pictured in Indigo Cavern in 2002.|
| This is one example of an ice tower that geoscientists believe is created when hot gas escapes from vents and freezes. Within the towers are caves or chambers that typically stay at a constant 1 degree Celsius. Photo courtesy of George Steinmetz, www.georgesteinmetz.com
|The accomodations at the Mount Erebus Volcano Observatory are "cozy." Scientists sleep in tents unless storms make the climate too unbearable. Hot water bottles make cold sleeping bags a bit more comfortable.|
Despite the amenities, no trip to a mountain top in Antarctica can be considered a vacation. The crew endures the hardships of living and working in extreme environments so they can accomplish ground-breaking science.
One reason Curtis came to New Mexico Tech was to study Erebus’ ice caves. He will be conducting geochemical experiments in the iconoclastic ice towers and ice caves of Erebus. As the volcano leaks gases through vents, the vapor freezes as soon as it hits the frigid Antarctic air. Over time, the frozen gases accrete into hollow towers of ice, some as tall as 30 feet.
“The ice towers are incredible structures,” Curtis said. “We’re not sure how directly volcanism interacts with the towers. No one has figured out exactly how they form.”
Curtis will spend much of his research time in the warm environment of the caves – most of which have an interior temperature of 0 to 5 degrees C. As with all experiments, the month in Antarctica is spent mostly gathering data.
Curtis will deploy a variety of sensors in the caves, testing the gas composition, temperatures, wind speed (or air flow) and the chemical compositions of the ice. He will also have some help with remote sensing of the ice towers. Laura Jones, with assistance from Jed Frechette from the University of New Mexico, will use a LiDAR -- or Light Detection and Ranging -- instruments to map Erebus’ lava lake. Jones will also create 3D images of the ice towers.
“Ground-based LiDAR is a new technique,” she said. “It’s an incredibly powerful tool, but it’s in its infancy. People use LiDAR as a mapping tool, but we can also look at how slopes change with time.”
Curtis and Jones hope to scan the towers twice this year and document changes in their size and shape. Over the course of several years, they hope to continue scanning the towers using LiDAR to further understand the geologic and chemical dynamics that affect the towers.
“Ice towers and ice caves are extremely rare,” Kyle said. “This is just the beginning of our study.”
The Tech team will also take ice cores from the towers to study the chemical composition of the ice walls. In coming years, Curtis expects the study of ice caves to involve biologists studying their microbiology.
“It’s worth emphasizing that these caves are a good analog to Mars,” Curtis said. “The biology may be quite interesting. In the long term, microbiology will be important because of the extreme environment and the UV shielding.”
Jones, a graduate of Indiana University, will also gather data from Erebus’ lava lake in an attempt to learn more about the internal processes that control the volcano.
Kyle compared the volcano to a human body, with lava functioning as the “blood” of the mountain. From visual observation, scientists see the lava lake rising and falling with a 10 minute cycle. Kyle notes that the volcano appears to be breathing. Jones will use LiDAR measurements to systematically monitor the way Erebus’ breathes.
Kyle said, “Our purely scientific objective is to understand the conduit, or feeder pipe, into the lava lake. It’s always convecting and moving. That’s something you don’t usually see at volcanoes.”
Previous expeditions have gathered gas data from the lava lake. This year, Jones will match LiDAR measurements with temperature and gas composition analyses. From Jones’ surface measurements, geoscientists will further gain more understanding of the active processes at work within the conduit that feeds the lava lake. As the years progress, as technology advances and as more scientists conduct new experiments, a vivid picture of Erebus begins to resolve more clearly.
Melissa Kammerer will focus her efforts on the chemistry of Mount Erebus with a special emphasis on a novel type of salt seen nowhere else on Earth.
“The gas from Erebus is very unusual,” she said. “It’s the most active and southernmost volcano. For more than a hundred years, it’s been sitting there, pouring out gasses; environmentally, it’s quite important.”
Erebus emits aerosols that consist of tiny solid particles. These are deposited around the volcano and can be examined to understand the degassing behavior of the volcano.
Most volcanoes emit gas which is mainly water, with smaller amounts of carbon dioxide. Erebus emissions are unusual with equal amounts of water and carbon dioxide, along with significant amounts of carbon monoxide and trace lelvels of acid gases rich in fluorine and chlorine. Compared to other volcanoes Erebus is very poor in emissions of sulfur, which typically is the third most abundant gas at other volcanoes.
“The plume gas contains sodium chloride, potassium chloride and other weird and wonderful things,” Kyle said.
Kammerer will collect samples from salt deposits with a high-tech device found in the kitchen – a teaspoon. She’ll get a little more scientific with plume samples, using a filter pack to collect aerosols. Once back in Socorro, she’ll analyze the samples using five different analytical methods.
The salt deposits are yellow, but contain no sulphur, Kyle said.
“We’re really curious about how the salts form,” Kammerer said. “It’s very reactive. This is a whole story we’ve not looked at. How do acid gases in the plume react with the rocks and how do the salts form? I’d love to be able to identify this salt.”
Kammerer has taken part in research expeditions to volcanoes in Costa Rica and Peru. She volunteered for the Erebus expedition because she loves volcanoes.
Jones came to Tech to study volcanic rocks in New Mexico but was easily attracted to a project on Erebus.
“I have no idea what I’m getting myself into,” she said.
– NMT –
Thomas Guengerich/New Mexico Tech
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