NOAA/WDS Paleoclimatology - Lake Punta Laguna, Mexico 3,500 Year Isotopic Data

Climate variability on the Yucatan Peninsula during the past 3500 yrs is reconstructed from the measurement of d18O in monospecific ostracods and gastropods in a 6.3-m sediment core from Lake Punta Laguna, Mexico. This late Holocene record is divided into three periods based on changes in mean d18O values. From ~3310 to ~178514C yr B.P. (Period I), low mean d18O values indicate relatively wet conditions (i.e., low evaporation to precipitation ratio,E/P). Mean oxygen isotopic values increased ~178514C yr B.P., and the interval between ~1785 and ~93014C yr B.P. (Period II) was distinctly drier than the periods before or after. The climate during the latter part of Period II was persistently dry, with exceptionally arid events centered at ~1171, 1019, and 94314C yr B.P. (equivalent to 862, 986, and 1051 A.D.). This interval of frequent drought was recorded at several other localities in Mexico and Central America, and coincided with the collapse of Classic Maya civilization. Following the last arid event, -18O values decreased abruptly at ~93014C yr B.P. (beginning of Period III), signaling a return to wetter conditions that have generally prevailed to the present, with the exception of a dry episode centered at 55914C yr B.P. (1391 A.D.). The paleoclimatic record from Punta Laguna provides evidence that multi-decadal and millennial-scale changes inE/Poccurred on the Yucatan Peninsula during the late Holocene. These wet/dry episodes may have influenced cultural evolution in Mesoamerica.