February 21, 2008

Satellites Provide Clues to Ancient Mayan Civilization

Five years ago, archaeologists began working with NASA scientists to better understand the mysterious end of the ancient Mayan civilization that thrived for over 1,000 years in Central America and southern Mexico.

The work is paying off,  according to archeologist William Saturno, who discovered ruins of hidden Mayan cities in the Guatemalan jungle with assistance from satellite images. The ruins consisted of five sprawling sites with hundreds of buildings. Saturno discovered the ruins through the use of a spy satellite that can see through clouds and forest to reveal differences in vegetation on the ground.

Saturno said the satellite images made it considerably easier to find ruins that were for hundreds of years hidden by dense jungle vegetation.  "It was like shooting fish in a barrel," he told Reuters.

Saturno began by seeking satellite images to find a water source near his San Bartolo excavation camp, 32 miles from the closest town on inaccessible roads.

NASA provided Saturno a snapshot of solar radiation reflected off of the plants in the region, and amazingly Saturno saw patterns of discoloration in the satellite image that outlined some of the buildings he had already uncovered. With his GPS device, he pinpointed the location on a map of other nearby discolorations and discovered several areas with hidden Mayan architecture.

The Maya used limestone and lime plasters in their building. As abandoned buildings disintegrated, chemicals from these stones seeped into the ground, preventing some plants from growing around the structures and affecting the chemistry of those that did grow.

From a 400-mile orbit, the satellite spotted these differences and provided Saturno a road map of the buried structures.

In 2001 Saturno discovered an elaborate mural from around 100 B.C. depicting the Mayan creation myth, dubbed the Sistine Chapel of the Mayan world.  He now hopes to have similar discoveries with the help of these satellite images.

Tom Sever, Saturno's research partner at NASA, hopes the satellite images will help solve the mystery of why the Mayan civilization collapsed around 900 A.D.

"What we are investigating is the choices the Maya made that ultimately created a catastrophic situation for them," said Sever from his NASA base in Alabama, in a Reuters telephone interview.

To support a population boom the Maya destroyed huge swathes of jungle for agriculture, and collected huge reservoirs of water called "bajos" to farm during seasonal dry spells.  But ultimately the deforestation raised temperatures and reduced rainfall, drying up water sources, explained Sever.

Indeed, the scientists found Bajos at around half the new sites located by the satellite, potentially corroborating this theory of why the Maya fled their cities.

Solving the mystery of the Mayas could help modern societies in better planning and "avoid the sometimes disastrous mistakes of the past," according to Sever. "We are in a race against time to preserve our history."


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