Lacustrine cave carbonates: Novel archives of paleohydrologic change in the Bonneville Basin (Utah, USA)

摘要: Records of past changes in lake levels and water isotopic composition closed basins provide key insights into variations the hydrological cycle; however, these records are often limited by dating precision temporal resolution. Here we present data from lacustrine cave carbonates, a previously unexplored class carbonates that comprise promising new archive hydrologic Bonneville Basin northeastern Great (USA). These dense precipitated within caves, crevices, other protected spaces flooded Lake during its highstand last glacial period. We report on deposits Cathedral Craners located !50 km apart at similar elevations approximately 100 m above modern Salt almost 200 below Bonneville’s shoreline. Carbonates two caves show chronologies, mineralogical transitions, compositions, uranium concentrations. findings suggest record level chemistry water. Importantly, can be precisely dated U‐Th methods, providing first balance tied to precise ages. Close agreement between paired calibrated 14 C ages suggests minimal (o200 a) carbon reservoir effect allows used for age control portions less suitable dating. use onset cessation carbonate deposition offer constraints saturation state also dated, high-resolution oxygen isotope deposits. Within phase reflecting lake’s transgression 26 18 ka, our large influx freshwater Heinrich Stadial 2. A hiatus beginning 18.270.3 ka may result freshening related overflow. Calcite resumes Cave 16.470.2 suggesting basin overflow had ceased this time calcite increased, andd O values increase markedly after 15.9 consistent with drying time. imply deglacial regression began well before Bolling warming. Cessation second 14.770.2 coincident warming, reflect drop Cave’s elevation. final stage aragonite 13.8 13.6 differs underlying facies not waters filling cave.