6th Grade Assessment – Unit 1 – RI.6.2, RI.6.3, RI.6.5, RI.6.8, L.6.4a
Directions: Read this article. Then answer questions 1 through 5.
by Beth Geiger
Where will you find the world’s best spot for stargazing? Many astronomers would say the
South Pole. The sky is always clear there, and during the winter it’s always dark.
Astronomers flock to the South Pole, as do scientists who study climate, the atmosphere,
and polar ice. To accommodate them, the U.S. National Science Foundation
5 (NSF) built an outpost, called the Amundsen-Scott South Pole Station.
Getting people and supplies to the station is not easy. Military transport planes do it
when weather permits. Therefore, the NSF is building a “highway” to the pole. The project is one
of the most unusual road-construction projects ever undertaken.
Top of the Bottom
The Antarctic highway, called the South Pole Traverse, will not be a typical
10 thoroughfare. “Everyone knows what a road looks like,” said Peter West, an NSF spokesman.
“What we are working on is not that at all, by any stretch of the imagination.”
When completed, the traverse will be a 1,600-kilometer (1,000-mile) path of groomed
snow and ice, marked by green flags. It will cross floating ice, gaping crevasses (cracks in the
ice), deep snow, treacherous mountains, and frozen nothingness.
15 The traverse is not a typical road, because
Antarctica is not a typical continent. Ice—
4,570 meters (15,000 feet) thick in some places—
covers 98 percent of the continent. Antarctica is
the world’s coldest desert and receives only about
20 5 centimeters (2 inches) of precipitation (rain or
snow) annually. The thick ice is the buildup of
millions of years’ worth of snowfall.
A few high peaks in the Transantarctic
Mountains poke through the ice to form islands
25 of rock called nunataks. East of the Transantarctic
chain is the polar plateau—the flat top of the
bottom of the world. On the plateau lies the
Antarctica’s ice doesn’t stop at the edge of the continent. Thick slabs of floating, slowly
30 shifting ice, called ice shelves, fringe the continent. The biggest, the Ross Ice Shelf, is the
size of France and is hundreds of feet thick.
The traverse begins at McMurdo Station, the main U.S. base on the continent. From
there, it heads across the Ross Ice Shelf.
Floating, shifting ice might seem like dangerous ground for heavy truck traffic. Why
35 not go straight over the land instead? Traveling across the Ross Ice Shelf keeps the journey at
the relative warmth of sea level for as long as possible. At higher elevations on land,
temperatures can get so cold that they cause machinery to malfunction. The shelf also
makes for relatively easy cruising. “It’s really smooth and flat,” said Erin Pettit, a University of
Washington geologist who works in Antarctica.
40 Building the traverse has been a daunting job. A hardy five-man crew works only during
the Antarctic summer (December to March). Even then, temperatures remain well below
freezing. “At first, it is strange for anybody to work in the cold-cold like that,” said project
manager John Wright. “But you learn to deal.”
The first summer, the crew members tackled their most chilling challenge: yawning
45 crevasses in the Ross Ice Shelf that can swallow a tractor in the blink of a frozen eyelash.
The crevasses, which can be 30 meters (100 feet) deep, might not be so dangerous if they
were visible. But most of them lurk under covers of snow called snow bridges. Many
people have fallen through snow bridges to icy deaths.
The nastiest crevasses on the route are in a shear zone about 48 kilometers (30 miles)
50 from McMurdo. There, ice within the shelf moves at different rates, stretching and cracking
into a maze of crevasses. To cross that area safely, the team members probed the ice ahead
with radar. Whenever they found a crevasse, they used a bulldozer to fill it in with snow.
Then they inched across.
During the last construction phase,
55 the crew worked for 66 straight days.
After filling crevasses in the shear
zone, the team bogged1 down in a
260-kilometer (160-mile) stretch of
deep snow on the shelf. The biggest
60 surprise, remembers Wright, was any
good day. “We had two last year,” he said.
bogged: to sink or get stuck