Paleo Slide Set: Climate and the Classic Maya Civilization
Hydrologic cycle of a closed-basin lake

Both Lakes Chichancanab and Punta Laguna are considered to be closed-basin lakes. 
Although the geology of Yucatan is karstic (consisting of porous limestone), many 
of the lakes are perched above the water table and isolated hydrologically by clay-basin seals. 
Closed-basin lakes have simple water budgets, and typically receive water by precipitation, 
slope wash, and groundwater seepage, while losing a majority of their water through evaporation. 
Therefore the lake volume, dissolved solute concentrations and oxygen isotopic ratios are largely 
controlled by the ratio of evaporation to precipitation. This characteristic makes closed-basin lakes 
climatically sensitive to the changing conditions of evaporation or precipitation. 

Photo Credits:
Patty Catanzaro 
Department of Geology, University of Florida