SYDNEY,
NSW, AUSTRAILIA: An Australian Aboriginal dreaming story has helped
experts uncover a meteorite impact crater in the outback of the Northern
Territory.
Duane
Hamacher, an astrophysicist studying Aboriginal astronomy at Sydney's
Macquarie University, used Google Maps to search for the signs of
impact craters in areas related to Aboriginal stories of stars or
stones hitting the ground.
One
story, from the folklore of the Arrernte people, is about a star
falling to Earth at a site called Puka. This led to a search on
Google Maps of Palm Valley, about 130 km southwest of Alice Springs.
Here Hamacher discovered what looked like a crater, which he confirmed
with surveys in the field in September 2009.
Cosmic
impact
The
crater is 280 m in diameter and about 30 m deep. Magnetic and gravitational
data collected from the site show the crater is bowl-shaped below
the surface and was likely caused by a meteorite a few metres in
diameter.
"There
is no other way to explain this than as a cosmic impact," said
Hamacher. "It couldn't have been erosion and there is no volcanic
activity in the area."
Macquarie
University co-worker, Craig O'Neill, added that a tiny amount of
'shocked quartz' had also been found at the site. "These were
very rare, but only form if a rock has experienced a shock blast
like that from a nuclear bomb or meteorite impact," he said.
The
research is described in papers Hamacher is preparing for submission
to the journals Archaeoastronomy and Meteoritics and Planetary Science.
Crater
spotting
Despite
the link to the dreaming story, weathering and the absence of meteorite
fragments suggest that the crater is millions of years old and humans
could not possibly have witnessed the event, Hamacher said.
Another
crater at Gosse's Bluff, 170 km west of Alice Springs, is 140 million
years old, and is also the subject of an Arrernte dreaming story
about a "cosmic baby" which fell to Earth.
Instead,
Hamacher thinks Arrernte Aborigines may have learned to recognise
craters from more recent impacts and then deduced the origin of
the Palm Valley and Gosse's Bluff craters. One more recent example
of craters created by an impact are the Henbury craters, 70 km from
Palm Valley and just 4,000 years old.
He
noted that his theory is speculation and the presence of the Palm
Valley crater near to the origin of the Arrernte story could simply
be a coincidence.
Hamacher's
comparison of known craters and Aboriginal stories about cosmic
impacts have not yet uncovered conclusive evidence that meteorite
impacts have been witnessed and incorporated into oral tradition.
But
he has found documented evidence of the Henbury craters being referred
to as "chindu china waru chingi yabu" by Aboriginal elders,
which he said roughly translates as "Sun walk fire devil rock".
Sacred
stories
The
Parks and Wildlife Commission of the Northern Territory notes in
its 2002 management plan for the Henbury craters, that it is aware
of related mythologies, but cannot share them, because they are
considered sacred and secret by the Aboriginal custodians of the
site.
Hamacher
said that he thinks it is possible that a direct link will be found
and that further research into dreaming stories could help uncover
new meteorite impact sites. He hopes to return to the area to talk
to Aboriginal elders about their stories.
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