This dataset includes tables of U- and Th-isotopic data used to calculate uranium-series age estimates (230Th/U method) and initial 234U/238U activity ratios for samples of tufa mounds formed by groundwater seepage. In addition, data include 87Sr/86Sr and 234U/238U values determined for spring discharge and streamflow collected from sites in the vicinity of Buffalo National River.

Multiple generations of spring-fed streams traversed ~800 km2 of the Las Vegas Valley in southern Nevada between ~10.9 and 8.5 ka, depositing an extensive tufa network. The scale of this network and diversity of tufa morphologies is novel in North America and offers an opportunity to obtain quantitative paleoclimate data for the region during the early Holocene. We determined isotopic compositions and estimated past temperatures using clumped isotope data from early Holocene tufa on the valley floor (698 m) as well as tufa forming today at higher elevation in the nearby Spring Mountains at Cold Creek Spring (1856 m). Modern and fossil tufa yielded comparably low d18O values, implying source waters for both were derived from high-elevation winter precipitation. Clumped isotope temperatures of modern tufa average 15.8±2.5°C, aligning with mean summer temperatures of the emergent spring water, and indicate equilibrium conditions of tufa formation. The early Holocene tufa yielded similar clumped isotope temperatures, averaging 15.2±3.9°C, meaning it precipitated at temperatures that occur at much higher elevations today. The Las Vegas tufa record, combined with nearby and temporally correlative paleospring and lacustrine records, suggest cool/wet conditions prevailed throughout the Mojave Desert during the early Holocene. These records also demonstrate that spring ecosystems responded to millennial-scale hydroclimate variations that supersede climate change driven solely by insolation. The previously unrecognized pattern of ecosystem response to hydroclimate documented here may assist in understanding climate drivers for the early Holocene and provide critical information for the fate of groundwater-dependent ecosystems in the southwestern U.S.

This data release contains tabular data (comma-separated-value files) of natural radiogenic isotopes of strontium, uranium, and thorium for samples of modern water, speleothems, associated with Fitton Cave, north central Arkansas, as well as rock that host the cave deposits. In addition, U-series ages (230Th/U dates and model 234U/238U dates) are calculated from those data for subsamples of speleothems. Stable isotopes of oxygen and carbon are reported for a subset of the stalagmite samples. Sample locations and descriptions as well as specific sub-sample imagery and narrative explanations are included as information supporting the analyses. Selected results are depicted as data plots in an accompanying Excel spreadsheet for non-interpretive illustration.

Radiogenic isotopes of strontium and uranium (87Sr/86Sr and 234U/238U) are useful tracers of water-rock interactions. Sr isotopic signatures in groundwater are derived by dissolution or exchange with Sr contained in aquifer rock whereas U isotopic signatures are more controlled by physicochemical and kinetic processes during groundwater flow. Insights into groundwater circulation patterns through the shallow subsurface at Yellowstone National Park can be aided by investigations of these isotopes. This data release contains tables with new isotope data consisting of concentrations (Sr, U) and radiogenic-isotope compositions (87Sr/86Sr, 234U/238U) for samples of thermal springs and geysers focused largely on the Upper Geyser Basin, but from other geothermal areas as well. Sr isotopes were also analyzed in samples of streamflow from several different areas in the Park as well as in samples of whole rock or mineral separates as a means of better defining sources of Sr that are incorporated into thermal water. Finally, authigenic mineral deposits precipitated from spring discharge inherit the Sr- and U-isotopic composition of the water from which they formed. Travertine precipitated from several areas in the Upper Geyser Basin were analyzed as a means of assessing their ages, determined by U-Th disequilibrium methods, and the Sr- and U-isotopic compositions of their source water at the time they formed.

Radiogenic isotopes of strontium and uranium (87Sr/86Sr and 234U/238U) are useful tracers of water-rock interactions. Sr isotopic signatures in groundwater are derived by dissolution or exchange with Sr contained in aquifer rock whereas U isotopic signatures are more controlled by physicochemical and kinetic processes during groundwater flow. Insights into groundwater circulation patterns through the shallow subsurface at Yellowstone National Park can be aided by investigations of these isotopes. This data release contains tables with new isotope data consisting of concentrations (Sr, U) and radiogenic-isotope compositions (87Sr/86Sr, 234U/238U) for samples of thermal springs and geysers focused largely on the Upper Geyser Basin, but from other geothermal areas as well. Sr isotopes were also analyzed in samples of streamflow from several different areas in the Park as well as in samples of whole rock or mineral separates as a means of better defining sources of Sr that are incorporated into thermal water. Finally, authigenic mineral deposits precipitated from spring discharge inherit the Sr- and U-isotopic composition of the water from which they formed. Travertine precipitated from several areas in the Upper Geyser Basin were analyzed as a means of assessing their ages, determined by U-Th disequilibrium methods, and the Sr- and U-isotopic compositions of their source water at the time they formed.

This dataset contains U-Pb isotopic data and associated ages of zircons within the lithologic framework of igneous, metaigneous, and metasedimentary rocks collected from the Seldovia quadrangle in southcentral Alaska. The samples were collected as part of geological mapping and research conducted from 2020 to 2023 and funded by the Mineral Resources Program of the U.S. Geological Survey. Zircon grains were separated and analyzed by GeoSep Services (GSS). All analyses were conducted between 2021 and 2023 using laser-ablation-inductively-coupled-plasma-mass spectrometry (LA-ICP-MS) techniques. Also described in this report are the major and trace element geochemical analyses for samples collected as part of the mapping project. Analyses were conducted by ALS Global. Major elements were determined from fused bead, acid digestion, and ICP-AES analysis. Loss on ignition (LOI) was determined by furnace or TGA. Also included are rubidium (Rb), strontium (Sr), samarium (Sm), and neodymium (Nd) analyses conducted by the ALS Scandinavia laboratory in Lulea, Sweden. Samples were prepared by alkali fusion. Sr was separated using Sr-specific column (TrisKem). Nd was separated from matrix first as sum of REE using a AG50-x8 column (AlfaAesar) and then from Sm on a Ln column (TrisKem).

This dataset includes tables of radiocarbon, uranium thorium series, and luminescence geochronologic ages and stable carbon and oxygen isotope compositions for sedimentary and organic samples.

This dataset includes tables of radiocarbon, uranium thorium series, and luminescence geochronologic ages and stable carbon and oxygen isotope compositions for sedimentary and organic samples.

This dataset includes tables of radiocarbon, uranium thorium series, and luminescence geochronologic ages and stable carbon and oxygen isotope compositions for sedimentary and organic samples.

This data set consists of digital water-level-change contour for the High Plains aquifer in the Central United States, 1980 to 1994. The High Plains aquifer extends from south of 32 degrees to almost 44 degrees north latitude and from 96 degrees 30 minutes to 104 degrees west longitude. The aquifer underlies about 174,000 square miles in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. This digital data set was created from 6,143 wells measured in both 1980 and 1994. The water-level-change contours were drawn manually on mylar. The contours were converted into a digital map at a scale of 1:1,250,000. The data should not be used at scales larger than 1:1,250,000.