Vinson Massif

The Vinson Massif extends between Goodge Col and Branscomb Glacier to the northwest, Nimitz Glacier and Gildea Glacier to the southwest and south, and Dater Glacier and its tributary Hinkley Glacier to the east. The southeastern part of the massif ends at Hammer Col, which joins it to the Craddock Massif, of which the highest point is Mount Rutford (). The massif comprises both the high central Vinson Plateau with its few peaks rising to over , and several side ridges mostly trending southwest or northeast from the plateau. The current height () of Mount Vinson was measured by a GPS survey that was conducted by the 2004 Omega Foundation team comprising Damien Gildea of Australia (leader) and Rodrigo Fica and Camilo Rada of Chile. From 1998 through at least 2007, the Omega Foundation kept a GPS receiver on the summit for a suitable period of time to obtain accurate satellite readings. ==Geology==

Steeply inclined strata known as the Crashsite Group forms Vinson Massif. It consists of of shallow-water, mostly marine, tan, green, and red quartzose sandstones (quartzites) and argillites. In ascending order, the Crashsite Group is subdivided into the Howard Nunataks Formation (), the Mount Liptak Formation (), and the Mount Wyatt Earp Formation (). Erosion-resistant and steeply inclined beds of the Mount Wyatt Earp Formation comprise the crest of the Vinson Massif, including Mount Vinson. The steeply inclined strata of the Crashsite Group are part of the western limb of a major syncline that forms the core of the Sentinel Range within the Ellsworth Mountains. The Mount Wyatt Earp Formation contains Devonian fossils. The transition beds at the base of the Crashsite Group contain Late Cambrian trilobites. The intervening lower parts of the Crashsite Group likely include Ordovician and Silurian strata. ==Climate and glaciers==

The climate on Mount Vinson is generally controlled by the polar ice cap's high-pressure system, creating predominantly stable conditions but, as in any polar climate, high winds and snowfall are a possibility. Though the annual snowfall on Mount Vinson is low, high winds can cause base camp accumulations up to in a year. During the summer season, November through January, there are 24 hours of sunlight. While the average temperature during these months is , the intense sun will melt snow on dark objects. Over successive years, the limited amount of snow that falls on Vinson Massif compacts and is transformed into ice, forming glaciers. These glaciers follow the topography and flow down the mountain's valleys. The uppermost glacier occupies Jacobsen Valley on the north face of Mount Vinson, and flows either into Branscomb Glacier to the west or Crosswell Glacier to the east. The Crosswell Glacier flows into the Rutford Ice Stream via Ellen Glacier. The south face of Mount Vinson is drained by Roché Glacier, which flows westwards into Branscomb Glacier, with the latter leaving Vinson Massif to join Nimitz Glacier. ==History==

A high mountain, provisionally known as "Vinson", was long suspected to be in this part of West Antarctica, but it was not actually seen until January 1958, when it was spotted by US Navy aircraft from Byrd Station. It was named after Carl Vinson, a United States Representative from Georgia who was a key supporter of funding for Antarctic research. The skyrunner Fernanda Maciel did the fastest ascent of Vinson in 6 hours and 40 minutes and round trip in 9 hours and 41 minutes from base camp. In January 2008, four Alpini of the Italian Army — Ettore Taufer, Giovanni Amort, Elio Sganga, and Marco Farina — completed the first ascent of Mount Vinson via a new route after a overland traverse from Patriot Hills. Unlike other expeditions, which are flown by helicopter to the mountain's base camp, the team skied the entire approach while hauling sledges. The route had never been attempted before and required 13 days of travel across Antarctic terrain to reach the base camp. The ascent from to the summit was completed over two days, with an intermediate camp at . This remains one of the longest unsupported approaches to Mount Vinson recorded. First ascent from east side While the vast majority of prior climbs to the summit have used the western side of the massif from the Branscomb Glacier, the first ascent from the east side was completed by an eight-person team sponsored by NOVA in January 2001. The team consisted of: • Conrad Anker – expedition leader • Jon Krakauer – mountaineer and author • Dave Hahn – mountain guide with 34 ascents, including ascents to Gardner, and Shinn. • Andrew Mclean – extreme skier • Dan Stone – glaciologist • Liesl Clark – producer • John Armstrong – cameraman • Rob Raker – assistant cameraman and sound recording The team not only made the first ascent from the east side but also performed scientific research into snow accumulation at different elevations as well as taking the first ground-based GPS reading from the summit. The GPS reading gave the elevation of the highest point in Antarctica as , eclipsing the earlier established heights recorded in 1959 and 1979. Another first was the successful aircraft landing of a Twin Otter on the Upper Dater Glacier on the eastern slopes of Mount Vinson. NOVA named the production "Mountain of Ice", which first aired on PBS in February 2003. ==See also==

• Vinson Massif. Scale 1:250 000 topographic map. Reston, Virginia: US Geological Survey, 1988. • D. Gildea and C. Rada. Vinson Massif and the Sentinel Range. Scale 1:50 000 topographic map. Omega Foundation, 2007. • Antarctic Digital Database (ADD). Scale 1:250000 topographic map of Antarctica. Scientific Committee on Antarctic Research (SCAR). Since 1993, regularly updated. ==References==