STRONTIUM ISOTOPE AND MAJOR ION GEOCHEMISTRY OF YALAHAU FRACTURE ZONE WATERS, YUCATÁN PENINSULA, MEXICO

The Yalahau Region, located in the northeastern portion of the Yucatán Peninsula, hosts a series of elongated depressions trending north/south in the direction of Isla Holbox, identified as the Yalahau Fracture Zone (aka Holbox). Previous studies have explored the geomorphology and various hydrologic characteristics of the Yucatan Peninsula; however, there is a gap in data concerning the interior region where the Yalahau fractures are located. Strontium isotope and major ion geochemistry data on the surface and groundwater of this region will serve as a hydrogeochemical fingerprint to aid in constraining the hydrological boundaries, determining direction of groundwater flow, and characterizing hydrogeochemical processes that impact the composition of the groundwater within the region. ⁸⁷Sr/⁸⁶Sr isotope ratios and ion concentrations are expected to differ from previously published data on surrounding aquifers and flow regimes, with the potential to distinguish different areas of groundwater recharge, storage, and flow direction. Gaining an understanding of the geochemical processes and the identification of the source region(s) of the waters is critical in determining the impact of various activities (e.g. extensive tourism, drinking water withdrawal, wastewater discharge/injection) that occur within the Yucatán Peninsula. The results of this study may have a significant effect on the contaminant risk of municipal water supplies that face northern coastal cities of the Yucatán including Chiquilá and the increasingly popular tourist destination, Isla Holbox.