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Megabeasts' Sudden Death
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Program Overview
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NOVA explores how scientists are working to solve the mystery of
what might have killed off ancient land animals nearly 13,000 years
ago.
The program:
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notes that Greenland's glaciers contain ancient microscopic dust
particles that provide environmental records dating back
thousands of years.
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announces one scientist's quest to find ice from the time of the
ancient land mammals' extinction and analyze its chemistry to
gain insight into what killed off the creatures.
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travels to southern Arizona, former home to at least 35 species
of now-extinct land mammals, including the saber-toothed cat,
the giant sloth, and several kinds of mammoths and mastodons.
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follows scientists as they travel to the black mat, a visible
layer of Arizona riverbed that reveals the extinction boundary.
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notes that Arizona was also home to the Clovis people—the
first documented humans to inhabit North America—who
apparently disappeared along with the animals.
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suggests two theories to explain the extinction: the human
overkill theory, which proposes that primitive humans may have
caused the extinction through overhunting, and the theory of a
sudden and drastic climate change.
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reports on traces of iridium found in the black mat—while
rare on Earth, iridium is prevalent in cosmic material,
suggesting that an asteroid or comet may have contributed to the
extinction.
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details the discovery of several types of nanoscale diamonds in
the black mat, including a hexagonal diamond that is thought to
form solely through an enormous high-pressure blast.
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features scientists who refute the comet impact theory.
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travels with scientists to Greenland, where they find nanoscale
diamonds—including hexagonal diamonds—deposited in
the narrow layer of ice from the time the great land animals
went extinct, supporting the theory that a comet may have played
a role in the extinction.
Taping Rights: Can be used up to one year after program is
recorded off the air.
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