Menicucci, Anthony J; Trask, James C; Schladow, S G; Spero, Howard J (2023): Geochemistry and paleoclimatology of Lake Tahoe from water and sediment stable isotopic analyses [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.925604

Here we present a multi-year dataset recording both precipitation and water column geochemistry from Lake Tahoe and regional precipitation between the Pacific coast (Bodega Bay, CA), central valley (Davis, CA) and Lake Tahoe Basin, collected over a three year period between 2010 and 2013. Precipitation data yield a regional meteoric waterline: δ2Hprecip. = 6.4 (±4.2) + 8.0 (±0.4) * δ18Oprecip. The Lake Tahoe water column data are from seasonal aliquots of water collected from 13 discrete depths between 0 and 450m in the northern part of the lake at the Mid-Lake sample station (39o 7.535oN, 120o 0.731oW). Sampling during each quarter year was done 1-2 times. The measured stable isotope values herein were averaged for each three month seasonal sampling period when multiple samples were collected in a quarter in order to provide resolution at the mean seasonal scale for each quarter year sampling interval. Lake Tahoe water is strongly influenced by the evaporation and precipitation balance of the basin. Maximum isotopic variability in the lake is observed in the epilimnion (shallower than 25m), with minor isotopic variability through the hypolimnion to near lake bottom at 450m. We also present the first analyses of Lake Tahoe δ18Odatiom from middle (~5500ybp) to late Holocene diatom frustules collected from sediment cores. Our δ18Odiatom data suggest mid-Holocene lake water was enriched in 18O by ~ 2-3‰ relative to lake water after 2,000 ybp. Lastly, we also archive the calculations for our water balance equations. Calculated values use the magnitudes of modern Lake Tahoe water mass balance components coupled with measured and estimated δ18O levels in these water balance components. We use estimates of E (evaporation)= 95.8 cm/yr and PRG (Precipitation, surface Runoff, and Groundwater) = 142.1 cm/yr (over the mean surface area of Lake Tahoe), which have previously been shown to be highly accurate over the recent long term water year (WY) average (mean value calculated from WY 1958 to 2004).