The ice of the white continent hides a rich geologic past. Scientists like those aboard our luxury expedition ship Le Commandant Charcot are beginning to understand what lies beneath.
Imagine a place of lush forests and wide flowing rivers where giant reptiles and amphibians roam. If you were to have visited, you might have thought you were in the jungles of the Amazon. Recently unearthed fossils suggest that you might even have come across dinosaurs and six-foot-tall creatures that resemble penguins.
But this was not the Amazon. This was Gondwana—the vast southern “supercontinent” of countless millions of years ago near the equator. Picture today’s continents and subcontinents of South America, Africa, India, and Australia conjoined like a jigsaw puzzle and you get the idea of the scale of it. Geologists believe Gondwana began to drift south until the planet’s tectonic plates split it apart, sending a large chunk of land to the South Pole. What we know as today’s Antarctica “arrived” at its current location some 100 million years ago. Then, between 10 and 25 million years ago, it began a cycle of cooling and heating.
Inasmuch as scientists can pinpoint a continent’s beginnings, this was Antarctica’s—likely named in 114 AD by Greek mapmaker and mathematician Marinus of Tyre for its location as the polar “opposite” of the Arctic (“anti-Arctic”). There is so much to uncover about this mysterious white continent—its history of exploration, its wildlife, even the culture of its research stations. Here, we dig into what makes its landscapes so unique and captivating: its geology. Join us for an Antarctica cruise as our onboard scientists illuminate its magnificence to you during our luxury small ship exploration.
An Early Glimpse of Antarctica’s Geography
A hand-sketched map of Roald Amundsen’s 1911 South Pole Antarctica expedition provides a geologic glimpse of what explorers experienced in Antarctica more than a century ago. On the map—extrapolated by Englishman Gordon Home from Amundsen’s telegraph reports—a dotted line traces the explorer’s route and gives a topographical sense of the white wilderness. The team set out from the Bay of Whales, where, Home wrote, a “Great Ice Barrier” met the shore, probably similar to the ice shelves first seen in 1820 by Russian expedition leader Fabian Gottlieb von Bellingshausen. Amundsen’s men then crossed what Home called a “Level Surface of Barrier Ice” before navigating a narrow valley, an ice field, and a “Mighty Mountain Range” he labelled “Queen Maud’s Ranges.” Then, after more than 900 miles, they became the first expedition team to reach the South Pole.
A Brief History of Millions of Years
Home’s map was the simplest of renderings of what scientists have since discovered. We know now, for instance, that West Antarctica (when it was part of Gondwana) reached into the Northern Hemisphere during the Cambrian period (which began 538.8 million years ago, or mya). East Antarctica was warmed by its then-equatorial climate. By the Devonian period (419.2 mya), Gondwana was shifting south until the Late Paleozoic ice age (360 mya) and the late Carboniferous (323.2 mya) ushered in a cooler climate. Flora, however, hung on—including ferns and the now-extinct seed plants known to horticulturists as glossopterids. The muddy soils in which the latter grew hardened into coal deposits.
The Permian period (251.9 million years ago)—known to some as the Great Dying—saw drier and hotter conditions. More than half of the world’s species were pushed into extinction. During the Mesozoic era (252 mya), new flora flourished, including conifers, gingko, and southern beeches. This was also when four-limbed creatures appeared. In the Jurassic period (201.3 mya), Gondwana began to split; Antarctica was eventually separated from South America by what we know today as the Drake Passage.
What We Know Now from Labs Like Those Aboard Le Commandant Charcot
You might think that an ice-covered continent is fairly homogenous, geologically speaking. But scientists like ours have been studying the polar regions from the laboratories on Le Commandant Charcot. And they have discovered that Antarctica is highly varied. However, because 99% of the land is blanketed by ice, it’s hard to know precisely what lies beneath, even with state-of-the-art imaging and radar capabilities.
Still, a lot can be extrapolated by observing the limited area of exposed rock. Geologists have seen that West Antarctica, for instance, shares much in common with the Andes. The soaring peaks you see from your luxury expedition ship were created by the same tectonic activity that made the South American range. In addition, study of the varied rocks in the Ellsworth Mountains and Antarctica’s highest peak (Mt. Vinson) further reveal that the western part of the continent was formed when several smaller plates collided, folded, and rose.
As for East Antarctica, it is composed of a larger continental shield of igneous and metamorphic rocks overlaid by various sedimentary rock such as sandstone, limestone, shale, and coal—the latter formed from plant matter from warmer geologic periods that’s been compacted over eons. Further, the basalt rock here was solidified from lava that once seeped up from underground and inundated the area in red-hot floods. By comparing these basalt rocks with those of, say, Australia, scientists can conclude that rocks from different continents have the same source—namely, a major volcanic event that helped to split Gondwana.