photo: NBC
Most people see Antarctica as a wide expanse of ice, with nary a change as far as the eye can see. But Antarctica is actually one of the most mountainous places on earth.
A very large river once flowed through it, easing between the crush of continental plates, shifting in primordial eras.
Looking at the astounding 3D map created by scientists of what Antarctica looks like beneath the icy expanse, one sees a geological turmoil, once that can only be explained by events that have shaped the continent into its extreme geological formation.
One of the largest glaciers in Antarctica sits atop a wide valley, Lambert Graben valley. Underneath the mile deep ice is a trench, which is both beautiful and forbiddingly deep.
Antarctica froze 34 million years ago. Before that the valley was much more even and flat, and the river flowed gently through it.
Admiralty mountains
Why then, did the gorge form where the river once flowed? By studying the sediments that escape to the sea before the glacial formations, the scientists have been able to realize that the glacier itself is not a static entity, but is active in a silent but forceful way. It erodes what lies beneath. The erosion rate, which was underway before the glacier set in from the river's flow, escalated once the glacier formed above it.
The glacier's heft, in fact, grinds upon the earth below as it shifts, and shaped the earth with time. Antarctica was formed when a large continental mass split in the Cretaceous era (80 million years approxim). Antarctica was then a place that teemed with life, arboreal and animal, as it drifted slowly southward.
Glaciers then are in constant, albeit very slow motion. They move because of the intense tectonic activity of the icy continent in past eras. Underneath all the ice lies a massive mountain range.
But the 3D map we have today does not tell us how the continent evolved, or what its aspect was millions of years ago. Until the ground underneath the ice is sampled and the stones analyzed, there is no way to tell what the geological composition of the ground was and its evolution.
But the 3D map we have today does not tell us how the continent evolved, or what its aspect was millions of years ago. Until the ground underneath the ice is sampled and the stones analyzed, there is no way to tell what the geological composition of the ground was and its evolution.
Gould Mountains
Antarctica was recently drilled offshore in an area facing the Lambert glacier. The sediments that have been collected tell of a long span of time, from 250 million until 34 million years ago, when the land was almost flat around the glacier's area. When the climate cooled 34 mllion years ago, the glaciers formed and started shaping the valley underneath it. The scientists estimate that the glacier has ground to dust almost 2.5 miles of rock, which was then transported to sea by the ice.
The buried mountain range, are central to the continent. They are called the Gamburtsev Mountains. The range was pushed upward during the rifting at the separation of the supercontinent of which Antarctica was part long ago. In what seem as two rapid uplifts 250 million and 100 million years ago, the earth was pushed upward forming the mountain peaks.
This points to an extremely stable geology and landscape preservation underneath the ice.
Source: NBC 3.8.13
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