Antarctica is often pictured as an immense, flat sheet of ice, but it is the world’s highest continent, possessing a complex, mountainous terrain hidden beneath the surface. The average elevation of the landmass is approximately 2,200 meters above sea level, a height largely due to the massive ice sheet. However, the continent’s bedrock holds extensive, towering ranges. These mountain systems rival the size and scale of many of the world’s most famous ranges and drastically shape the continent’s geology and the flow of its ice.
Confirmation and Scale of the Mountain Systems
The scale of Antarctica’s mountain systems remained largely unknown because the thick ice sheet conceals much of the bedrock topography. Researchers used specialized airborne radar and satellite technology to map the landscape beneath the frozen cover. These surveys revealed that many of the largest ranges are entirely subglacial, existing thousands of meters below the ice surface.
The most prominent example of a completely buried formation is the Gamburtsev Subglacial Mountains, located in East Antarctica. This system stretches for approximately 1,200 kilometers, comparable in size to the European Alps. The peaks are buried under as much as 3.1 kilometers of ice, yet some of its highest points reach an elevation of 3,400 meters.
The primary mountain system that visibly divides the continent is the Transantarctic Mountains (TAM). The TAM separates the stable East Antarctic Craton from the geologically active West Antarctic Rift System. This range is one of the longest on Earth, extending for approximately 3,500 kilometers across the continent, influencing the movement of the East and West Antarctic ice sheets.
The Major Named Mountain Ranges
The Transantarctic Mountains are composed of smaller, named ranges and massifs that define the continent’s interior geography. One of the highest points within this system is Mount Kirkpatrick, which reaches an elevation of 4,528 meters above sea level. This peak is situated in the Queen Alexandra Range, demonstrating the height achieved by mountains across the TAM.
The highest point on the continent is found in a separate system in West Antarctica, known as the Ellsworth Mountains. This range is situated near the Ronne Ice Shelf and is composed of two sub-ranges: the Sentinel Range and the Heritage Range. The Sentinel Range contains the continent’s highest peak, Mount Vinson, which reaches an elevation of 4,892 meters (16,050 feet).
The Ellsworth Mountains are a relatively short chain compared to the expansive TAM, yet they contain the six highest summits on the entire continent. Mount Vinson, often referred to as Vinson Massif, is a large dome of rock and ice that rises above the surrounding polar plateau.
Formation and Geological History
The geological forces responsible for forming Antarctica’s mountain ranges are diverse, reflecting the continent’s long and complex tectonic history. The Transantarctic Mountains (TAM) are a non-volcanic range whose uplift began approximately 65 million years ago, coinciding with the opening of the West Antarctic Rift System. This uplift is primarily the result of rifting, a process where the continental crust on the edge of the stable East Antarctic Craton was lifted as the crust stretched and thinned in the adjacent rift valley.
The height and steep slopes of the TAM are attributed to a combination of thermal processes and mechanical forces. Heat flow from the underlying mantle caused the crust to expand and rise. The convergence of crustal material against the rigid East Antarctic block contributed to the mountain-building process. This type of uplift, known as rift-flank uplift, contrasts with the compressional forces that create ranges like the Himalayas.
Other ranges, such as the Ellsworth Mountains, formed through compressional forces during the ancient Gondwanide Orogeny, a mountain-building event in the late Paleozoic and early Mesozoic eras. The Ellsworth block is believed to have been a microplate that rotated to its present position as the supercontinent Gondwana broke apart. The East Antarctic Ice Sheet has also played a role in the preservation of the mountains, particularly the subglacial Gamburtsev range, where the ice has protected the peaks from erosion.