West Fork Whiterocks River, Utah: stable isotope and hydrochemical data for rock glacier water, streamwater, and groundwater

Water draining from rock glaciers in the Uinta Mountains of Utah (USA) was analyzed and compared with samples of groundwater and water from the master stream in a representative 5000-ha drainage. Samples were collected during the melt season of 2021 using automated ISCO samplers. Two samplers were installed at springs discharging from the termini of rock glaciers. A third sampler was installed at a non-rock glacier spring, and the fourth was deployed along the West Fork Whiterocks River. Composite samples of summer and fall rain were also collected, as well as grab samples of snow. Samples were analyzed for their stable isotopic composition using a Los Gatos 45-EP Triple Liquid Water Isotope Analyzer at Middlebury College. Samples were run against a bracketing set of 5 standards and calibrated with a cubic spline function. Each sample was analyzed 10 times, with the first 2 injections discarded to minimize cross-over. Standards were run as unknowns after every five samples as an internal check on the results. Accuracy of the instrument is 0.4‰ for δD and 0.1‰ for δ18O. The standard deviation of repeat injections of the samples in this study was 0.17‰ for δD and 0.04‰ for δ18O. Hydrochemical characterizations were made with a Thermo iCap ICP-MS at Middlebury College. Samples were run against a set of standards derived from NIST Standard Reference Material 1643f “Trace Elements in Water”. An in-house standard was used to determine the abundance of Si and Ti, which are not present in 1643f. The NIST standard and the in-house standards were run after every 10 unknowns and a linear correction was applied to compensate for instrument drift. Interpretation focused on elements that consistently exhibited concentrations >1 ppb.