Speleothem based quantification of precipitation and aridity and its role for Maya cultural development on the northern Yucatán Peninsula, Mexico

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The varied cultural evolution and final collapse of Maya civilization in Mesoamerica are heavily debated issues and discussions include the impact of both natural (e.g. droughts, hurricanes, volcanic eruptions), and social disasters (e.g. warfare and unsustainable economy). An increasing number of records report unusual dry conditions coinciding with hiatuses in construction, phases of temporary urban abandonment and population collapse. Previous reconstructions indicate that environmental conditions and precipitation on the Yucatan Peninsula were distributed very heterogeneously in space and time. In addition, the duration and chronology of events remains uncertain. Hence, in this project we propose to improve the timing and chronology of rainfall patterns (i.e. droughts and extreme precipitation) through the study of geochemical tracers at high resolution in speleothems from Estrella cave. This would thus permit to improve the coherence of paleoclimate change and Maya cultural evolution in northern Yucatan. As part of a DFG funded pilot-project we have discovered that Estrella cave near Valladolid not only hosts important Maya archaeological remains, constructions, and a graveyard, likely dating to the early classical Maya period, but also numerous speleothems with potentially unique climate information spanning the entire Maya era. Preliminary high precision 230Th/U-ages demonstrate continuous growth of stalagmites over more than 3000 years including the Maya evolution and reaching to even historical times. Furthermore, first analyses show that the incorporation of certain trace elements in these stalagmites is strongly related to changes in recharge above the cave. We will here generate a novel, replicated, uniquely resolved and accurately dated record of past precipitation in the area based on proxy analysis of trace elements and stable C and O isotopes in these speleothems. Through these records, along with comprehensive compilation of climate and cultural information, we will evaluate the influence of catastrophic natural events such as droughts, volcanic eruptions, hurricanes, and their compound specific impact on the Maya cultural history. This project, and a geochemical monitoring program, is supported by local speleologists, climate scientists and archeologists.