Showing posts with label Antarctica. Show all posts
Showing posts with label Antarctica. Show all posts

Gamburtsev Subglacial Mountains' Mystery Solved

The mystery of how the Gamburtsev Subglacial Mountains in the Antarctic was formed has been solved. The range is at a high elevation and was only discovered in 1958. It is buried under 3,000 meters of ice.

A group of scientists used aircraft with magnetometers, gravity meters and ice penetrating radar. They found that the mountains had been there for a billion years. The range spreads out in a 1,800 long earth fracture reaching from the eastern Antarctic to India.

This region of the Earth has been relatively free of tectonic activity. A billion years is short in tectonic terms, so the mountains have sharp edges not greatly worn away by water, wind and snow.

The rift system also contains the largest subglacial lakes on the Antarctic continent. Before animals roamed the Earth micro-continents collided to form the thick crustal root on which the mountain range stands. As the mountains eroded the root was preserved, frozen by the bitter cold. When dinosaurs existed 250,000 years ago supercontinent Gondwana broke away, the crustal root warmed which pushed the mountains even higher. Less than 50 million years ago the Antarctic ice formed over the range protecting it again.
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Geology

Penguins Moved to Africa Many Times But Died Out

Penguins are funny little creatures though they are interesting to study. They first made landfall in Africa millions of year ago but they went extinct. They had a second go at colonization. This failed as well.

They preferred Antarctica, South America and Australia living there for a very long time. There are two ocean currents that could have brought penguins to Africa. Neither goes further north than the equator so colonization would have occurred only in south west Africa.

The third or perhaps fourth intrusion onto the African continent was successful. Blackfooted Penguins live their today. They are related to other banded penguins found in South America and the Pacific. There is evidence that four other types of penguins once existed in Africa. These were analysed to see if they were related. Two of the four were sufficiently complete for this. They were found not to be related to Blackfooted penguins or to each other, so colonization happened many times.
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Science