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Bookshelf science

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Editor’s note: Marine geophysicist Robin Bell is leading an expedition to Antarctica to explore a mysterious mountain range beneath the ice sheet. Following is the sixth of her updates on the effort as part of ScientificAmerican.com‘s In-Depth Report on the "Future of the Poles."

McMURDO STATION, ANTARCTICA—For a geologist, Antarctica can be a very frustrating continent.  Stepping off an aircraft onto the ice, one is greeted by a 12,000-foot smoking volcano on one side and a mountain range rising about 14,000 feet on the other.  This would appear to be a geologist’s dream.  The problem is the ice. Only 1 percent  of the rock on the continent is free from the veil of ice.  The rest is hidden from prying scientists.  We are forced to rely on remote sensing techniques to tell us about the types of rocks beneath the ice sheet.  Our team uses radar, gravity and magnetics. Other scientists shoot off small explosives or release pressurized air to record the echoes from different layers of hidden rock.

Because our work is in the middle of the ice sheet, we rarely see any rocks. Given their absence, I did not expect to find an extensive collection of Antarctic rocks while picking up the iridium satellite phones for our field party from the McMurdo communications center.

The McMurdo communication center is one of the many metal-sided buildings in the science city beneath the smoking Mt Erebus.  The entrance is a yellow metal ramp that brings you to a pale green building. Beyond the heavy metal door on one side is the young red-headed women, who distributes the Iridium satellite phones and VHF radios;  across the hall is Bill Nesbitt, a 21-year veteran of Antarctic work in charge of communications for the region. Nesbitt is reserved, and a bit intimidating.. He had responded  with very short notice to my team’s last minute request for Wi-Fi and a phone at our canvas tent at the airfield. (Wi-fi and phones seem to work much better than the VHF radio these days.) However, I really wanted to look at the bookcases in his office that were filled top to bottom with rocks of all shapes, sizes and colors. 

The communication systems that support McMurdo, South Pole and the science operations throughout the continent require towers installed on some of the tallest peaks. Nesbit has been traveling to the tops of these peaks for over 20 years to ensure people working with the U.S. National Science Foundation in Antarctica can communicate. During his trips to these mountain peaks, he clearly has taken a moment to soak in the magnificent exposure of rocks along the edge of the continent and to collect samples that tell the tale of the continent’s history. The lack of any trees  or shrubs in Antarctica means that in ice-free areas the rocks are beautifully exposed. Nesbitt’s bookshelves tell much about the history of fire and ice in Antarctica.  

Propped against the bookcase is a piece of a magma chamber beneath an ancient volcano. This cylindrical piece of white and black speckled granite comes from a borehole drilled for monitoring the Comprehensive Test Ban Treaty.  Below, a polished piece of red sandstone reflects a time when the region was covered with vast inland seas instead of ice.  Now this of piece of a beach carried the mark of the current climate.  The once rough piece of rock that sits in Nesbitt’s office is as smooth a piece of china but sculpted into intricate patterns of pits and ridges. 

My fingers are drawn to run across the very smooth surface and trace the cups where centuries of ice crystals driven by the wind have polished and carved the rock. Funny how flying ice crystals makes a surface as smooth as a skating rink.  In the central position on the bookshelf is a shiny black rock about the size of a basketball that weighs only about one  pound.  Encrusted with complex patterns resembling taffy, this rock is a piece of frothy lava spit out of the lava lake atop Mt Erebus probably in the last decade. 

The bookshelf hidden in a metal-sided building is a reminder that both fire and ice continue to mold this continent.

Dispatches from the Bottom of the Earth: An Antarctic Expedition in Search of Lost Mountains Encased in Ice

 

Photo courtesy of Robin Bell.





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