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A Little About Antarctica

Antarctica is our southernmost continent, located primarily south of the Antarctic Circle (60°S).  Looking at the continent using our standard globe it seems to provide a bottom cap, covering the South Pole.  It is the antipodes of the Arctic.  (Antipodes are considered diametrically opposite so that if you were to draw a line straight through the center of the Earth you would connect the points.) Antarctica and the Arctic are opposite in more ways than one!  One big opposite is that Antarctica is primarily ice covered land, while the Arctic is primarily ice covered ocean.

While the Antarctic continent ranks only fifth in size (larger than Europe and Australia), it is large enough to fit the full United States in its 5.4 million square miles (~14 million sq. km) size.

Geographically the Continent is divided by a large Mountain Range known as the Trans Antarctic Mountains.  This range creates a spine between the Weddell Sea and the Ross Sea, and separates the peninsula and West Antarctica from the much larger section that is mostly in the eastern hemisphere called East Antarctica. In what might be considered another situation of opposites, West Antarctica is small fragments of continental crust covered by ice sheet and lying primarily below sea level, while East Antarctica is largely an expanse of continental crust at sea level, covered by an ice sheet averaging a thickness of 2,000 meters (m) but ranging from ~1,000 m to 4,500 m.

Geologic Supercontinents - How did Antarctica fit into the 'puzzle'

Geologically we know that millions of years ago Antarctica was part of several super continents that existed:  Rodinia (formed ~1.1 bya), Gondwana (existing ~500 to 200 mya), and then later Pangea (existing ~250 mya).  In order to better demonstrate where and how Antarctica fit into this series of super continents, we have used a real puzzle. Looking at the images above you can see through time how these super continents shifted and rearranged. Antarctica shifted around inside the 'continent puzzle' but remained positioned alongside other future continents like India, Africa and Australia. Notice how as part of Rodinia, Antarctica was located right on the equator, and would have experienced a mild tropical climate!  Even 500 my later during the time of Gondwana, the Antarctica section of continent was still fairly close to the equator, and experiencing a relatively mild climate. Both Rodinia and Pangea stretched across the center of the planet in a reach across the equator that came close to connecting the two poles.

While geologists refer to these super continents as part of a shifting Earth landscape, in relation to the human existence they had extremely long lives. Rodinia existed for some 350 million years. How long is that? Well consider that the entire history of human's on Earth spans between 2 and 5 million years (depending on how you define 'humans'), 350 million years is a considerable period of time.

Rodinia
GONDWANA
Pangea
Rodinia formed in the Precambrian, as long as 1.1bya. During this time the piece of land mass that would one day become Antarctica spanned the equator with warm tropical climates.
Gondwana formed in the Cambrian, ~500 mya. Gondwana was the southern most of two continental masses, with Laurasia in the Northern Hemisphere. Most of Gondwana, including the Antarctica piece, had shifted south falling below the equator.
Pangea formed ~250 mya in the Permian period. By this time period Antarctica had shifted and rotated to the south moving down in latitude towards the Southern Pole. The Antarctic climate would have been cold.

 

So Just How Old is The East Antarctic Continent?

We know from the discussion above that the Earth's continents are constantly reforming. As they move apart and together they collide and fuse together forming new sections of land and mountains; they subduct sliding under sections of land; or they spread/stretch apart thinning out and forming rifting areas. With all this shifting there are some sections of continental crust that have remained deep in the interior of the larger continents, and have experienced very little of the above activity. East Antarctica is just such an area.

Scientists believe the crustal formation of  East Antarctica is old and stable.  Composed of continental crust dating back at least 500mya,   the  East Antarctic continental crust is referred to as  Precambrian craton. Precambrian refers to the early time period of its origin (~3.8 billion years ago to ~550 mya), and a craton is defined as the stable interior part of a continent that has not been affected by tectonic activity in recent geologic time. Putting these two facts together we are looking at a very old block of durable continental crust.

This project is focused deep in the center in East Antarctica, the most remote and unexplored area of our planet.  This inhospitable environment boasts the most extreme environment on Earth with some of the highest, driest and coldest locations on, not only the Antarctic continent, but the whole planet.  To learn more about what questions we are hoping to answer in our research click on the Gamburstev Mountain or Subglacial Lakes links. To get a sense of Geologic Time and how long ago the Precambrian was, do the activity on the education page on "Geologic Time". To examine clues on what life have been like in the Precambrian do the activity on "Life in the Precambrian"on to the education page.

 

 

 
       
 
This project funded through NSF Antarctic Research Grants #ANT 0632292; ANT 0619457| contact us | web master
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