Belize's 'Blue Hole' Holds Clues to Collapse of Mayan Civilization

Belize's "Blue Hole," a famous underwater cave and series of nearby lagoons, may hold clues to the collapse of the ancient Mayan civilization, according to new research.

According to mineral samples taken from the site, a century-long drought lasting from 800 AD to 900 AD could be to blame - a time that coincides with their catastrophic collapse. This study isn't the first to say that a lack of rain led to the demise of the Mayans, but it does strengthen the argument because scientists studied several spots in the region, rather than just one, Live Science reports.

Up until 700 AD, the Mayans were a thriving culture in the Yucatan peninsula, building great pyramids and practicing astronomy, agriculture, writing and mathematics, but then the civilization slowly descended into warfare and anarchy and began its decline. Factors like deforestation and the society's fear of evil spirits have been linked to their downfall, but drought seems more and more the likely reason.

The scientists believe that a shift in the weather system called the intertropical convergence zone (ITCZ) was the main driver of this drought. The ITCZ normally dumps rain on the Yucatan peninsula during the summers, but supposedly this monsoon system skipped over the region during the Mayan collapse.

The researchers aimed to solve this mystery by drilling holes into the sediments of the famous Blue Hole. Over thousands of years, runoff from rivers and streams during periods of copious rainfall deposited layers of sediment in the Blue Hole's lagoon, offering scientists a geological timeline to study the ancient climate.

"It's like a big bucket. It's a sediment trap," study co-author André Droxler, an Earth scientist at Rice University, told Live Science.

A chemical analysis of these cores, particularly the ratio of titanium to aluminum, implicated periods of low rainfall with times when the Mayans were disappearing. Specifically, between 800 AD and 1000 AD when the Mayan civilization collapsed, there were just one or two tropical cyclones every two decades, as opposed to the usual five or six.

"When you have major droughts, you start to get famines and unrest," Droxler added.

The Blue Hole, according to National Geographic, is more than 1,000 feet (300 meters) across and some 400 feet (120 meters) deep. The hole is the opening to what was a dry cave system during the Ice Age. When the ice melted and the sea level rose, the caves were flooded, creating what is now a natural wonder.

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