EMPIRICAL ORTHOGONAL FUNCTION TIME SERIES ANALYSIS OF A STALAGMITE GEOCHEMICAL RECORD FROM YUCATÁN, MEXICO

Empirical Orthogonal Function time series analysis of a multivariate stalagmite geochemical record can provide insight into the frequency and severity of high-magnitude events as well as land use changes over the cave. The stalagmite used in this study was collected in 2007 from Cenote Chaltun-Ha in the Yucatán Peninsula, Mexico, cross-sectioned vertically, and polished. In two separate previous studies, a Laser Ablation-Inductively Coupled Plasma Mass Spectrometer (LA-ICPMA) was used to measure the concentrations of 18 elements across the stalagmite’s annual layers, and the stalagmite annual layers were measured and counted. The top part of the stalagmite, the section used in this study, has recorded the past ~500 years. We applied the new annual age model to generate a high-resolution time-series record of trace element variations. By applying advanced statistical time series analysis to the multivariate dataset, we aim to separate the impacts of volcanic eruptions from other factors such as changes in land use on the ranch over the cave or flooding events from hurricanes. During that time there were many eruptions of Central American arc volcanoes including Paricutin, which produced large quantities of ash that could have cooled and dried the regional environment and left a record within the stalagmite as changes in the concentrations of multiple trace elements. Our analysis reveals the extent to which the northern Yucatán region was affected by high-magnitude events and cycles such as the El Niño Southern Oscillation and solar cycles. This study adds to a small but growing body of research showing that volcanic activity plays important roles in karst, and that speleothems are potentially important terrestrial archives of past explosive volcanism and regional tephra deposition.