Ancient a cave a window to why the Mayan world came to an end

News Limited Network
November 14, 201212:08PM

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AS the Mayan calendar enters its final count-down, researchers are making inroads into understanding why the ancient American civilisation collapsed.

And the probable reason all the Mayan cities were all abandoned over a thousand years ago has a familiar sound to it: Climate change.

While the modern version is not likely to become catastrophic on December 21 (the date the Mayan Long Count calendar expires), new research suggests changes in the weather brought the Mayans to their knees.

A study published in the November issue of the journal Science adds evidence to this increasingly accepted view.

A stalagmite from a cave near the Mayan city of Uxbenka in Belize contains a record written in its stone of weather conditions over a period of several thousand years.

According to study leader and Pennsylvania State University environmental anthropologist Douglass Kennett, a stark picture of boom and bust emerges when compared with the stone-etched records of the Maya.

Protected by its dark, cool cave, the stalagmite preserves tiny doses of oxygen isotopes in each new layer of sediment deposited each wet season.

It is in these oxygen atoms that the every year's rainfall conditions leave their stamp. The oxygen atom will contain eight, nine or ten neutrons at its core - a variation dependent upon the amount of water present when the sediment was formed.

With this atomic counter, scientists have been able to track the climate of Central America over the past 2000 thousand years. They can even zero in on the conditions in a given six-month period.

The stalagmite reveals there was a period of unusually wet conditions between 440 and 660AD. This coincides with Mayan records of a major expansion of its cities and a growth in the reach of the empire .

Some of these cities housed 60,000 people, and the iconic Mayan stepped-pyramids sprung up in Guatemala, Belize and the Yucatan Peninsula of Mexico.

Rainforests were cleared and vast fields of maize planted to feed the burgeoning populations.

It was a golden age of Mayan sport, philosophy, astronomy, agriculture and bureaucracy.

But the rain did not last. The stalagmite shows a drought had struck shortly after 660AD - and for the next 300 years the rains gradually dwindled in frequency and intensity. Mayan records for this period depict increasing war, upheaval and political rivalries.

"Mayan systems were founded on (high) rainfall patterns," Kennett said. "They could not support themselves when patterns changed."

The sediments show the extreme drought continued for 80 years between 1020 and 1100AD.

During this time, the Mayans suddenly stopped inscribing their history in their stone buildings and tablets.

They simply up and left their cities to find food.

This was the true Mayan apocalypse.