Geography | Polar Unbound

Geography

ANTARCTIC ICE SHEET

Surrounded by the Southern Ocean, Antarctica is home to about 90%
of the world’s ice and 70% of the world’s freshwater. 98% of the continent is covered by the
Antarctic ice sheet. On average this sheet of ice is about one mile thick, though can reach 2.5 miles thick in places. If all this ice were to melt, sea levels would rise two hundred feet. The
continent’s coast is over 95% ice; this ice safeguards the South Pole positioned almost perfectly at the heart of the continent.

RIVERS, LAKES, MOUNTAINS & VOLCANOES

There are more than four hundred lakes in Antarctica, a large number of rivers and extensive mountain ranges. In keeping with Antarctica’s massive size and tendency for one-upmanship, we’re going to tell you about the biggest, highest, and longest. 

The longest river is the Onyx, though the Onyx only stretches for twenty miles despite its claim to fame—and can also only be found during the continent’s short, paltry summer. It flows through the Wright Valley as meltwater from the Lower Wright Glacier. No fish live in the river, due to it being frozen for most of the year. However, like most Antarctic rivers, the Onyx does support a
number of microscopic lifeforms, most notably algae.

Located at the Pole of Cold, Lake Vostok is the continent’s largest lake as well as one of the largest subglacial lakes in the world. The surface of Vostok is over 13,000 feet below the
surface of the ice, putting it at almost two thousand feet below sea level. Due to its depth, Vostok was not discovered until 1993, though Soviet explorers and scientists first posited its existence in 1959 almost forty years prior. Sealed off from earth’s surface for millions of years, Vostok remains a location of scientific inquiry and significance; if life of any kind is discovered in its depths, it would be a breakthrough and would also support theories of the existence of life on
Jupiter and Saturn’s moons Europa and Enceladus.

The Ellsworth Mountains are the continent’s highest mountain range. Over two hundred miles long, thirty miles wide, and over 16,000 feet high at Mt. Vinson Massif, the range is bisected by the Minnesota Glacier, splitting it into the northern Sentinel Range and southern Heritage Range.The Sentinel Range is much larger and also houses the towering Vinson Massif. With an average temperature of -20 °F, the best time to attempt a summit of these mountains is in the summer months from November to January. 

There are also several active volcanoes in the region, with Mount Erebus being the world’s southernmost active volcano. The most recent major eruption was from Deception Island in 1970. However, minor eruptions are more common and lava flows have been observed frequently in recent years. Several underwater volcanoes have also been discovered; the underwater volcano most recently discovered in 2004 off the coast of the Antarctic Peninsula might even be active.