Paleo Slide Set: Climate and the Classic Maya Civilization
Extruded core from Lake Chichancanab with abundant white shell material in the core.

When the cores are returned to the lab, they are split in two halves. One-half of 
the core is sampled and the other half is archived for future use. The core that was 
sampled from Lake Chichancanab had a total length of 4.9 m with a basal radiocarbon age 
of 9000 years BP. The sedimentation rate averaged about 0.5 mm per year. The core was 
sampled continuously at 1-cm intervals over its length. A 1-cm sample in the Lake Chichancanab 
core represents about 20 years of deposition. The sedimentation rate determines the temporal 
resolution of study and as a result, scientists are able to reconstruct climatic changes that 
lasted for multiple decades or longer. The sediments of Chichancanab consisted of alternating 
layers of organic matter, calcite, and gypsum.

The total core length from Punta Laguna was 6.3 m with a basal age of 3300 years. The sedimentation 
rate averaged 2 mm/year, which is about four times greater than the sedimentation rate in the core 
from Chichancanab. A 1-cm sample for the Punta Laguna core represents only 5 years of deposition, 
permitting the resolution of much shorter climatic events. Sediments in the Punta Laguna core are
composed almost entirely of calcium carbonate(CaCO3). 

Photo Credits:
David A. Hodell 
Department of Geology, University of Florida