Tuesday, September 15, 2009

What do dinosaurs and the Maya have in common?

One of the world's most famous asteroid craters, the Chicxulub crater, has been the subject of research for about twenty years. The asteroid impact that formed it probably put an end to the dinosaurs and helped mammals to flourish. Together with an Anglo-American team, an ETH Zurich researcher has studied the most recent deposits that filled the crater. The results provide accurate dating of the limestones and a valuable basis for archaeologists to research the Maya.

Science Daily reports:
The discovery of the Chicxulub asteroid crater was detective work: in 1980, based on iridium anomalies in clay sediments – which could only be formed extraterrestrially – the American physicist Walter Alvarez postulated a devastating asteroid impact (see box) at the transition from the Cretaceous to the Paleogene around 65 million years ago. Another ten years passed before the associated crater was discovered on the Yucatan peninsula. Research work since then has focused mainly on the structure of the crater, which has been buried in a layer of sediment up to two kilometres thick since its formation and which can only be studied using boreholes or geophysical methods. Little is known about the sediments close to the surface. Most of the geological maps also originate from the time before the Chicxulub crater was discovered, and do not completely reflect the geology. Read more here.