SSS 2012-02-28(在线收听

 This is Scientific Ameican 60 second Science, I'm Cynthia Graber, this will just take a minute!

 
Cave painting connects us with our prehistoric artist ancestors. But there's a dearth of such illustration in the Americas. Now a cave in Brazil has been found to house the oldest New World image known. 
 
The shelter was excavated from 2002 to 2009. In the last days there, scientists exposed a foot-high figure in the bedrock. It has a c-shaped head, two outstretched arms, two legs, and a very visible penis.
 
Using radiocarbon dating, the researchers dated an ash layer to between 9300 and 10,500 years ago. A hearth found about an inch above the drawing gives similar results. And the researchers used a technique called optically stimulated luminescence on sediment, which also dated to around 10-12,000 years ago.
 
The scientists say this makes the petroglyph the oldest reliably dated cave art in the Americas. The research was published in journal Public Library of Science One. 
 
Echoes of this style exist in other early art in the region, amidst diverse styles throughout North and South America. The researchers the range of images reveals a spectrum of symbolic thought dating back to early in the history of human colonization of the hemisphere.
 
Thanks for the minute, for Scientific American 60 second Science, I'm Cynthia Graber
  原文地址:http://www.tingroom.com/lesson/sasss/2012/2/172986.html