[meteorite-list] No Evidence Found of Catastrophic Impact 12, 900 Years Ago

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 1 Oct 2010 13:44:00 -0700 (PDT)
Message-ID: <201010012044.o91Ki03F019158_at_zagami.jpl.nasa.gov>

FOR IMMEDIATE RELEASE FROM

THE UNIVERSITY OF ARIZONA

Oct. 1, 2010
 
This story and photos are online at http://uanews.org/node/34499

Contact information follows the story.

UA Archaeologist, Colleagues Find No Evidence of Catastrophic Impact

Anthropology professor Vance T. Holliday and others take issue with claims
that a comet strike led to the demise of Paleoindian megafauna hunters
during the Pleistocene.

The notion of an object such as a comet or asteroid striking the Earth and
wiping out entire species is compelling, and sometimes there's good evidence
for it. Most scientists now agree that a very large object from space
crashed into what is now the Yucatan Peninsula in Mexico 65 million years
ago, altering climate patterns sufficiently to end the age of the dinosaurs.

The theory was backed up by supporting evidence, and while not everyone in
the scientific community was on board at first, it's now generally accepted.

For about three years, a similar controversy has been brewing about the end
of the Pleistocene, when ice sheets covered large parts of the planet and
animal behemoths foraged the landscape. Prehistoric hunters developed
sophisticated strategies and tool kits for bringing down mammoths and other
megafauna.

Did a comet striking one of those ice fields in North America nearly 13,000
years ago sufficiently alter climate enough to wipe out these animals and
collapse the cultures that hunted them?

A new study published in Current
<http://www.journals.uchicago.edu/doi/full/10.1086/656015> Anthropology
argues that whether or not such an extraterrestrial event occurred, nothing
in the archaeological record indicates that the Clovis hunters suddenly
disappeared along with the animals.

Vance T. Holliday, a professor in the University of Arizona School of
Anthropology and the department of geosciences, and David J. Meltzer, an
archaeologist at Southern Methodist University, studied evidence from a
number of archaeological sites and concluded that it was more likely that
hunting populations shifted their subsistence patterns to hunting other
animals.

The controversy began several years ago when scientists cited evidence of an
extraterrestrial impact 12,900 years ago somewhere around the Great Lakes
caused the Younger Dryas climate changes, the extinction of several large
mammal species and the collapse of the Paleoindians whose large, fluted
spear points - first found near Clovis, N.M. - were likely designed for
hunting very big game animals.

Supporters of the comet theory point out that few Clovis sites continued to
be occupied after their inhabitants stopped making large projectile points.
Those few old Clovis sites that are reoccupied by post-Clovis people also
show a significant passage of time - as much as five centuries - between
them.

Holliday and Meltzer, bolstered by radiocarbon dates from more than 40
sites, counter that most prehistoric sites are kill sites where game was
dispatched and butchered, and not likely to be continuously occupied. Gaps
across time and the disappearance of Clovis points, they said, were more
likely the result of shifting settlement patterns brought about by the
nature of a nomadic existence.

"Whether or not the proposed extraterrestrial impact occurred is a matter
for empirical testing in the geological record," Holliday writes. "Insofar
as concerns the archaeological record, an extraterrestrial impact is an
unnecessary solution for an archaeological problem that does not exist."

Contact: Vance T. Holliday, (520) 621-4734, vthollid at email.arizona.edu
Received on Fri 01 Oct 2010 04:44:00 PM PDT