New evidence from a Mexican lake bed has revealed that an unusually severe drought about 1,200 years ago may well have contributed to the abrupt decline of classic Maya civilization.
Scientists from the University of Florida at Gainesville said that an analysis of sediments beneath Lake Chichancanab on the Yucatan Peninsula provided "the first unambiguous evidence" for a period of extreme aridity between the years 800 and 1000.
The drought was the harshest in the region in 8,000 years and coincided with the widespread collapse of Maya culture, a time of spreading warfare and finally the abandonment of many great cities of monumental architecture.
Although in recent years archaeologists have made many new discoveries in Maya ruins and managed to decipher telling hieroglyphic texts, the mystery of the civilization's sudden decline a thousand years ago persists.
Various theories have implicated overpopulation, environmental degradation and bitter intercity rivalries leading to destructive warfare throughout much of the Maya lowlands of what is now Mexico, Guatemala, Belize and Honduras.
And now, in a report being published today in the journal Nature, scientists added regional drought as a possibly critical factor in the civilization's fate.
The findings from a chemical analysis of shell carbonate and gypsum, burned grasses and root fragments in cores from the lake bed might not alone support the drought theory, they said, but other geological evidence of low lake evidence elsewhere in Mexico and Costa Rica suggested the climate shift was just in Central America.
The study was conducted by Dr. David Hodell and Dr. Jason Curtis, both geologists at the University of Florida and Dr. Mark Brenner of the university's department of fisheries and aquatic sciences.
In an accompanying commentary, Dr. Jeremy Sabloff, director of the University of Pennsylvania Museum of Archaeology and Anthropology and a Maya specialist, said the new findings add "another important component to the model that archaeologists are currently building to help explain the upheavals of the late eighth century and early ninth century A.D. in the Maya lowlands."