Paleoclimatic Variation in the Valley of Guatemala during Precolumbian Times

Background of the Project

At present very little is known regarding the paleoclimate of highland Guatemala. The information that we have is based largely on a number of paleoclimate investigations that have been carried out in recent years in the lowland regions of Mesoamerica. These data were obtained by sediment coring in lakes Petén Itzá, Quexil, Salpeten and Petenxil (Brenner, 1994; Curtis et al., 1998; Islebe et al., 1996; Leyden et al., 1993) in the Department of Petén, with similar investigations in the Yucatán peninsula, including Lake Cobá and Cenotes San José Chulchacá, Sayaucil, and Chichancanab (Curtis et al., 1996; Leyden et al., 1996; 1998) Additional studies have been carried out in the Candelaria watershed (Gunn and Folan, 1995; Gunn, Folan and Robichaux, 1995). Lake sediments are particularly useful for determining ancient climate patterns because they often contain pollen which provide clues to the nature of the ancient vegetation in the area, phytoliths as indicators the presence of maize agriculture, and microfossils (ostracods and gastropods) which are sensitive to temperature and humidity changes.

The chronology for the lowland paleoclimate sequences that began at the termination of the Pleistocene glacial period is based on radiocarbon dating with climatic inferences established largely on the basis of pollen and isotope geochemistry (δ ₁₈O) of carbonate shells. These data can be used to infer past changes in the relation between evaporation and precipitation (E/P). By this means, the following pattern of alternating cool/dry and warm/wet periods in the Precolumbian Guatemala lowlands and Yucatán was determined (Leyden et al., 1996):

It remains to be determined whether the Guatemala highlands reflect a similar pattern or what differences may exist in comparison with the lowlands. It has been noted that the most severe dry period in northern Yucatán occurred around 900 – 1000 A.D., a time contemporary with the collapse of Maya civilization (Hodell et al., 1995; Curtis et al., 1996). It seems very probable that climatic stress was one of the factors that complicated the deteriorating situation at the end of the Classic period. It may be that wet and dry periods among geographically distant sites coincided, suggesting that climatic events were widespread and may have played a critical role in cultural developments. However, it is not known to what degree climatic events in the lowlands were comparable to with those in the Guatemala highlands, nor whether changes in weather patterns in both regions were simultaneous with one another. Without adequate climatic reconstructions from highland sites, the effects of climatic change in the region cannot be inferred.

It was in view of the above consideration that we initiated our study of the paleoclimate of the Valley of Guatemala. The valley is situated at an altitude of 1500 m above sea level and is the location of a major Precolumbian site, Kaminaljuyú, where considerable archaeological investigations have been carried out in recent years. It was hoped that we might obtain a record of temporal climatic patterns in this area over the past 3000-4000 years, with a special focus on the period 1000 B.C. to 1000 A.D., the time that Kaminaljuyú was flourishing.

Table of Contents  |  Next Page

Return to top of page