martes, 15 de septiembre de 2015

Australia. Ancient campfires show early population numbers

RADIO carbon data from prehistoric occupation sites are providing insights into Australia’s fluctuating human population levels tens of thousands of years ago.

ANU archaeologist Alan Williams used radio carbon dating technology to examine charcoal dates from more than 1000 prehistoric campfires and based on this he says populations appear to have increased steadily until 25,000 years ago.

He did this by examining the isotope Carbon 14 (14C), which is absorbed by all living things from the atmosphere.

Their remains then lose the isotope at a steady rate after they die, and Carbon 14 levels provide reliable dates for any organic matter up to about 35,000 years old.

Dr Williams compared these dates with climatic change profiles provided by a recent synthesis of Australia’s palaeoclimate from the OZ-INTIMATE (Australasian INTegration of Ice core, Marine and TErrestial records) project. [...] sciencewa.net.au/t