Fichier:Taylorglacier pho 2013 studinger.jpg

Taylorglacier_pho_2013_studinger.jpg(720 × 480 pixels, taille du fichier : 153 kio, type MIME : image/jpeg)

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English: While flying over Antarctica aboard a P-3 aircraft in November 2013, Operation IceBridge project scientist Michael Studinger took this photograph (top) of Taylor Valley, one of Antarctica’s unique dry valleys. Home to Taylor Glacier, striking rock outcrops, and Blood Falls, the valley is one of the most remote and geologically exotic places in the world.

While ice and snow covers most of Antarctica, Taylor Valley and the other dry valleys are conspicuously bare. Inland mountains—the Transantarctic Range—force moisture out of the air as it passes over, leaving the valley in a precipitation shadow. The lack of precipitation leaves dramatic sequences of exposed rock. In both the satellite image and photograph, the tan bands are sandstone layers from the Beacon Supergroup, a series of sedimentary rock layers formed at the bottom of a shallow sea between 250 million and 400 million years ago. Throughout that period, Earth’s southern continents were locked into the supercontinent Gondwana.

The dark band of rock that divides the sandstone is dolerite (sometimes called diabase), a volcanic rock that forms underground. The distinctive dolerite intrusion—or sill—is a remnant of a massive volcanic plumbing system that produced major eruptions about 180 million years ago. The eruptions likely helped tear Gondwana apart.

The dominant feature in the photograph—Taylor Glacier—is notable as well. Like other glaciers in the Dry Valleys, it is “cold-based,” meaning its bottom is frozen to the ground below. The rest of the world’s glaciers are “wet-based,” meaning they scrape over the bedrock, picking up and leaving obvious piles of debris (moraines) along their edges.€
Date acquired November 19, 2013
Source http://earthobservatory.nasa.gov/IOTD/view.php?id=82524&src=eoa-iotd
Auteur Michael Studinger, NASA
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actuel13 décembre 2013 à 20:53Vignette pour la version du 13 décembre 2013 à 20:53720 × 480 (153 kio)Tillman{{Information |Description ={{en|1=While flying over Antarctica aboard a P-3 aircraft in November 2013, Operation IceBridge project scientist Michael Studinger took this photograph (top) of Taylor Valley, one of Antarctica’s unique dry valleys. Ho...

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