[meteorite-list] Scientists Probe Odessa Meteor Crater

[Ron Baalke]

http://www.oaoa.com/news/nw060204b.htm

Scientists probe Odessa meteor crater

University of Arizona researchers hope to learn more about when
the impact occurred.

By Cliff Hamilton
Odessa American (Texas)
June 2, 2004

A team of University of Arizona scientists took samples of 
millennia-old dust in the Odessa meteor crater Tuesday hoping to 
learn more about the region's geological history.

Vance Holliday, a professor of anthropology and geoscience, said 
the team missed its goal of taking core samples as deep as 80 feet.

"We only got to 53 feet. It would've been nice to get to 70, but 
we'll manage," he said.  Despite not reaching 80 feet, Holliday 
said he thinks the samples collected can still help pinpoint the 
crater's age.

"We'll still be able to get a reasonable approximation of the age. 
We got pretty close I think," he said. "This is a terrific core. 
It's by far better than anything we've seen before."

Tuesday was the third time Holliday led a team to take samples 
from the crater since 2001. Last year, the digging stopped at 20 
feet when the corer couldn't punch through a caliche layer.

Holliday and his team were trying to take core samples of the 
soil that would indicate when the meteor crashed into the soil.

"We know it's on the order of tens of thousands of years," he 
said Tuesday morning.  "Basically what we're trying to do is to 
get as deep as we can and date the sediment that's filled in the 
crater."

Holliday said knowing the crater's age would help paint a picture 
of the changes in the Odessa landscape over eons.

He said it could also give insight into the history of meteoric 
impacts on the earth's surface. "The more data points we can get, 
the better understanding we can get of the frequency of impacts," 
he said.

Research assistant James Mayer said knowing how old the crater is 
would give him a point of reference for his research into 
environmental change in the high plains region.

"A key to the whole thing is figuring out how old this damn thing 
is," Mayer said.  Mayer said the team would use carbon dating and 
a process called luminescence dating to determine the crater's age.

Holliday said the samples might even provide a more detailed 
picture of the landscape than he expected.

He said he suspects the crater had served as a shallow, temporary 
lake at some point in its history, which is indicated by the 
different soil types in the samples.

But Tuesday's sample indicated the crater was filled with water 
at a different time than the sample taken last year.

"This core is different than last year's, and I think it's telling 
us more about the history that we didn't know before," he said. 
"There's a good story here."