UnderOriental Antarctica one extends one 1200 km long mountain range and up to 3400 m highthat of Monti Gamburtsevinvisible to our eyes because they are hidden by hundreds of meters of ice. A new study conducted by a team of Australian researchers and published on Earth and Planetary Science Letters clarified how and when these mountains have formedanswering a question that has remained open since they have been discovered over fifty years ago. The mountain ranges, in fact, are formed in active areas from a tectonic point of view, while Eastern Antarctica in this respect has been stable for hundreds of millions of years. The researchers, analyzing details minerals called zirconidetermined that the Gamburtsev mountains originated about 600 million years ago due to the collision between busty plaques that led to the formation of the Supercontinent Gondwana.
The discovery of the Gamburtsev mountains
Under the Antarctic glacial cap there is a buried landscape consisting of ancient valleys, plains and mountains that up to 34 million years agowhen in Antarctica the climate was temperate, they were free from ice. Later, a global climatic coolingdue to the decrease in CO2 in the atmosphere, led to the formation of the glacial cap. The ice covered almost all of the continent, but the peaks of some mountain ranges are still visible. However, this does not happen for the Gamburtsev mountains, which are entirely covered with hundreds of meters of ice.
Since we cannot see these reliefs, their discovery, which took place as part of a Russian shipping in 1958was possible thanks to the use of seismic techniques. Their find has aroused enormous amazement also for the size of these reliefs: 1200 km long and up to 3400 m high, they are comparable to ours Alps. They are also one of the best preserved mountain ranges on the planetsince the ice protected them from erosion.
How the origin of the Gamburtsev mountains was discovered
To get new information on this mountain range, the researchers analyzed tiny zircon crystals Found to hundreds of kilometers away at the Prince Charles mountains in the sediments of river origin. These sediments, which over time turned into sandstones, were transported by rivers that descended from the Gamburtsev mountains before they were buried by ice. Zirconi are rare minerals that contain uraniumwhich progressively transforms into lead using a period of time known to us. Therefore, identifying how much uranium to date has turned into lead has been possible to give the formation of these minerals. The zirconi originate from the solidification of the magma: this means that when they trained in correspondence with the Eastern Antarctive, processes of fusion of the rocks occurred, which accompanied the formation of the mountain range.
The formation of the Gamburtsev Mountains
On the basis of the age of the zirconi, it has been established that the Gamburtsev mountains originated approximately 600 million years ago. More precisely, about 650 million years It does two large continents first separated from the ocean collided at the South Pole contributing to the formation of the Supercontinent Gondwana (which included Africa, South America, Australia, India and Antarctica). The terrestrial crust raised originating in reliefs that approximately 580 million years ago they reached the height of the peaks of the Himalaya. As the reliefs raised, the rocks deeply warmed up and merged partially by flowing to the side. This phenomenon caused the sinking of some parts of the mountain range. In the coming years, new details will probably emerge on these reliefs, as well as on the rest of the landscape buried under Antarctica. The continent is in fact at the center of an increasing interest from the researchers, who only a few months ago published a new map that shows Antarctica for how it would appear without the ice that covers it. The map, created as part of the Bedmap3 international project, is the result of over 60 years of detections.
