Antarctica: The Lost World

Antarctica: The Lost World

Antarctica is located almost completely south of the Antarctic Circle and covers an area of ​​14.2 million km2.

Described as a polar desert, the continent has an average annual rainfall of 166 millimeters and is covered in ice up to 1.9 km thick.

Antarctica holds the record for the lowest measured temperature on Earth, -89.2 °C (-128.6 °F), but despite the harsh climate, it is home to native species of mites, nematodes, penguins, seals, tardigrades and forms of lichen or moss.

When Robert Falcon Scott led the ill-fated Newfoundland expedition to Antarctica between 1910 and 1913, his men were found dead with fossils of the Glossopteris tree, a genus of the extinct order of Permian seed ferns that became extinct during the end of the Permian (Changhsingian) mass extinction.

Although Scott’s expedition was seen at the time as a tragic hero’s folly, the discovery of the Glossopteris fossils proved that Antarctica was once a forested landscape full of green and life. Other samples of Glossopteris fossils in Australia, New Zealand, Africa and India would suggest that Antarctica was joined to the other land masses and continents.

From the end of the Neoproterozoic era until the Cretaceous, Antarctica was part of the supercontinent Gondwana. The formation of Gondwana began between 800 and 650 Ma with the East African orogeny, the collision of India and Madagascar with East Africa, and was completed between 600 and 530 Ma with the orogenies of Brasiliano and Kuunga superimposed, the collision of South America with Africa and the addition of Australia and Antarctica, respectively.

During the Cambrian period, West Antarctica was partially in the Northern Hemisphere, while East Antarctica was at the equator where invertebrates and trilobites flourished in tropical seas.

Antarctica saw a period of glaciation during the Late Paleozoic Ice Age between 360 and 260 Ma as it approached the South Pole. After deglaciation in the second half of the early Permian, the landscape was transformed by Glossopteris (first discovered in Scott’s expedition), with later species of Cordaitales, sphenopsids, ferns and lycophytes.

During the Triassic, Antarctica was dominated by pteridosperms of the genus Dicroidium, as well as associated Triassic flora such as ginkgophytes, cycatophytes, conifers and sphenopsids. It was during this period that the first tetrapods migrated, and paleontologists found fossils belonging to the fauna of the Lystrosaurus area.

The Jurassic and Cretaceous period saw the arrival of dinosaurs of the genus Cryolophosaurus and Glacialisaurus, first discovered in the Transantarctic Mountains, with some evidence of Antarctopelta, Trinisaura, Morrosaurus and Imperobator.

After the breakup of Gondwana beginning 180 Ma, Antarctica was completely isolated from the other continents, leading to the creation of the Antarctic Circumpolar Current (ACC).

Models of Antarctic geography and the ACC suggest that the current, in combination with reduced carbon dioxide levels, led to the creation of permanent ice caps that extended until the continent was completely ice-covered.

Header image credit: Shutterstock

#Antarctica #Lost #World

Leave a Comment

Your email address will not be published.