Was this the
trigger of the “Great Dying” mass-extinction event (and a host of wild
conspiracy theories)?
A NASA
satellite detected a 300-mile-wide “gravity anomaly” below the ice of
Antarctica consistent with a giant asteroid impact and the volcanic flows of
Siberian Traps that continued for roughly two million years and spanned the
Permian–Triassic mass extinction, which occurred between 251 to 250 million
years ago. The impact crater is estimated an nearly three times the size of the
Chicxulub crater that ended the dinosaur epoch (image above), and presumably
formed before the Cretaceous formation of the east Antarctic coast.
The Gravity
Recovery and Climate Experiment (GRACE) was a joint mission of NASA and the
German Aerospace Centre that ran from March 2002 to October 2017. By measuring
gravity anomalies, GRACE showed how mass is distributed around the planet and
how it varies over time.
However, one
discovery in Antarctica has received far more attention than the rest of the
mission. In 2006, a team of researchers led by Ralph von Frese and Laramie
Potts used GRACE data to discover the anomaly below the ice. The team
determined this to be a massive impact crater buried below the ice for millions
of years, likely caused by an asteroid.
New 2018
details on the east Antarctic gravity field from the Gravity Recovery and
Climate Experiment (GRACE) mission revealed a prominent positive free-air
gravity anomaly over a roughly 500-kilometer diameter buried basin centered on
Antarctica’s in north-central Wilkes Land.
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