Hidden beneath the vast ice sheet that characterizes Antarctica, the Transantarctic Mountains rise as one of the longest and oldest mountain ranges on the planet. This range, extending over 3,500 kilometers from Cape Adare in Victoria Land to Coats Land in the Weddell Sea, forms a crucial geographic and geological boundary: the divide between East and West Antarctica.

Despite their isolation and extreme climate, these mountains tell stories of primordial times, unique biological adaptations, and heroic explorations. Formed over 65 million years ago during the opening of the West Antarctic Rift System, the Transantarctic Mountains bear witness to a fascinating geological history.

Their sedimentary layers, known as the Beacon Supergroup, contain records of remote epochs when Antarctica was not an icy continent but a green and forested land.

Transantarctic Mountains
The Transantarctic Mountains divide Antarctica into East and West Antarctica. Credit: NASA / Public domain / Wikimedia Commons

Within these formations are fossils of ferns, mosses, and trees like the Wollemi pine and southern beeches, the last vestiges of a warm past before the gradual cooling associated with the breakup of Gondwana.

The uplift of the range reached its peak in the Eocene, about 34 million years ago, coinciding with the onset of Antarctic glaciation. Unlike the younger mountains of the continent, which have volcanic origins, the Transantarctics are primarily composed of sedimentary rocks resting on an even older basement of granite and gneiss.

These geological features make them a living testimony to Earth’s tectonic history and one of the oldest examples of global orogenic activity.

Transantarctic Mountains
Image of the Transantarctic Mountains taken from NASA’s P-3 airborne laboratory on November 27, 2013. Credit: Michael Studinger / NASA / Public domain / Wikimedia Commons

The range, a natural barrier dividing the Antarctic Plateau, is dotted with peaks like Mount Kirkpatrick, which rises to 4,528 meters, and is home to glaciers that flow perpendicularly to its slopes, acting as frozen arteries connecting East Antarctica to the Ross and Weddell Seas.

These glaciers, in addition to carving the terrain, have revealed subglacial features previously unknown through advanced technology, redefining models of ice behavior in this remote region.

Among the mountains, the McMurdo Dry Valleys stand out as a climatic and geographic anomaly. Devoid of ice due to a lack of precipitation and the action of intense katabatic winds, these valleys offer a glimpse into a nearly Martian landscape. Here, where extreme temperatures and aridity challenge life, microbes, fungi, and lichens survive, adapted to some of the most hostile conditions on the planet.

Transantarctic Mountains
A seal appears in its spiracle in the sea ice of the Ross Sea with the Transantarctic Mountains in the background. Credit: Hannes Grobe / Wikimedia Commons

One of the continent’s most peculiar rivers, the Onyx, flows intermittently through the Wright Valley, fed by seasonal meltwater. Its short 30-kilometer course ends in Lake Vanda, where evaporation exceeds inflow, leaving notable salinity in its depths. This extreme ecosystem is a natural laboratory for scientists who use it to understand the limits of life in conditions akin to those of Mars.

Although terrestrial life is limited in the range, adjacent coasts, such as those of the Ross Sea, host rich biodiversity. Adélie and emperor penguins, Weddell seals, and leopard seals thrive in these coastal areas, while birds like the giant petrel and the south polar skua soar above the region in search of food. The food chain here is a reminder of biological resilience in one of the world’s most extreme ecosystems.

Since their discovery in 1841 by explorer James Clark Ross, the Transantarctic Mountains have been a challenge for adventurers and scientists. During the Heroic Age of Antarctic Exploration, figures like Ernest Shackleton, Robert Falcon Scott, and Roald Amundsen confronted the range in their attempts to reach the South Pole. Each used different routes, such as the Beardmore and Axel Heiberg glaciers, to cross this imposing natural barrier.

Transantarctic Mountains
Transantarctic Mountains as seen from Cape Hallet. Credit: Andrew Mandemaker / Wikimedia Commons

Amundsen, the first to reach the Pole in 1911, stood out for his skillful planning, while the tragedy of Scott and his team, who perished on their return, added an epic and dramatic note to the history of these mountains. Today, the remnants of those expeditions, such as huts and personal items, are considered protected historical sites, monuments to human resilience and tragedy.

The scientific importance of the Transantarctic Mountains has not diminished over time. During the International Geophysical Year of 1957–1958, aerial and ground investigations enabled more precise mapping of the range, uncovering unique geological features and reinforcing its role as a natural laboratory. The construction of stations such as McMurdo and Scott facilitated access to the region, though mountaineering and other private activities remain restricted to preserve its pristine environment.

In the dry valleys, research on glaciers, climate, and microorganisms continues to provide insights into the planet’s past and future. Additionally, international efforts have established specially protected areas and sites of historical interest to ensure that this region, one of the most remote and untouched on Earth, remains a sanctuary for science and nature.


The Transantarctic Mountains in the background, as seen from Victoria Land.This article was first published on our Spanish Edition on December 19, 2024: Las Montañas Transantárticas que dividen la Antártida en dos partes son una de las cordilleras más antiguas de la Tierra


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