a. Carbon Isotope Data

Note: No formal accuracy tests were conducted and these data are disseminated to allow discussion related to methods. Sample Analyses: Samples were processed at both the USGS in Menlo Park, CA, and at UC Berkeley following established methodology for separating organic material from sinter (Howald et al., 2014; Lowenstern et al., 2016; Slagter et al., 2019). First, the exterior surface of each sample was removed using a rock saw, and then any further material was removed if there was any visible algal material in the interior of the sample. Second, samples underwent a series of chemical baths. Samples were crushed and soaked in 30% hydrogen peroxide for 48 hours to remove any remaining modern algae. Once cleaned,...

Categories: Data; Tags: Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, geysers, radiocarbon dating, All tags... sinter, Fewer tags

d. X-ray Fluorescence (XRF) Data

Sample Analyses: Samples were analyzed for major and trace element concentrations of the unreacted and reacted sinter using a Thermo ARL Perform’X X-ray fluorescence (XRF) spectrometer at the Hamilton Analytical Laboratory at Hamilton College, New York, following protocols described in Johnson et al. (1999). One-part powdered sample is mixed with 2 parts Li-tetraborate flux and fused at 1000 °C in graphite crucibles. The cooled wavelength dispersive XRF (WDXRF) pellets are re-ground to powder and re-fused at the same temperature. Flat analytical surfaces are ground on steel-backed diamond laps. XRF determinations of 44 element concentrations are calibrated with approximately 70 reference materials. Net peak intensities...

Categories: Data; Tags: Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, geysers, x-ray fluorescence

f. Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) Data

Sample Analysis: Cation concentration data was obtained as a part of the beryllium isotope analyses. Samples collected from the Upper Geyser Basin were first treated in clean laboratory facilities at the University of New Hampshire following the methods laid out in the “Beryllium Isotope Data” portion of this data release. Following the hydrofluoric acid (HF) etches, and prior to Accelerated Mass Spectroscopy (AMS) analyses of 10Be, opal purity was assessed by measurement of major cation concentrations via inductively coupled plasma-optical emission spectrometry (ICP-OES) using a Perkin Elmer Optima 3300DV at the Analytical and Technical Services lab at SUNY College of Environmental Science and Forestry in Syracuse,...

Categories: Data; Tags: Geysers, Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, cation

g. X-ray Powder Diffraction (XRPD) Data

Sample Analyses: X-ray powder diffraction (XRPD) was carried out on samples UGB-TD-24 through UGB-TD-39 (excluding UGB-TD-38) at the U.S. Geological Survey in Menlo Park, CA. Each sample was powdered using an agate mortar and pestle and packed into a shallow well (0.5 mm) aluminum XRPD mount with the knife edge of a spatula to ensure random orientation. Samples were scanned continuously at room temperature from 3.0° 2θ to 80.0° 2θ with a step size of 0.01° 2θ on a Rigaku Multiflex X-ray diffractometer with Cu-Kα radiation with an accelerating voltage of 40.0 kV and a filament current of 20.0 mA. Database Contents: The data files (UGB-TD-XX.csv; where XX is the respective sample ID) contain the angle and intensity...

Categories: Data; Tags: Geysers, Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, x-ray diffraction

b. Uranium and Thorium Isotope Data

Sample Analyses: Four samples of silica sinter from Giant and Castle Geysers composed of opal-A or opal-A/C were analyzed for U-Th isotopes at USGS laboratories in Denver, CO (https://www.usgs.gov/centers/gecsc/science/denver-radiogenic-isotope-lab?qt-science_center_objects=0#qt-science_center_objects). Small fragments, weighing approximately 10 g, were cut and polished to enable microsampling using carbide dental burrs. Sub-samples consisted of small pits or trenches that cut across microfabric elements and integrate material weighing 0.082–0.109 g. Resulting powders were digested using concentrated hydrofluoric acid (HF) after spiking with known amounts of a mixed 229Th-233U-236U tracer solution. After evaporation,...

Categories: Data; Tags: Geysers, Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, radiometric dating, All tags... thorium, uranium, uranium-thorium analysis, Fewer tags

e. Laser Ablation Inductively-Coupled Plasma Mass Spectrometry (LA-ICP-MS) Data

See child items for two LA-ICP-MS datasets, including sample collection and methods descriptions.

Categories: Data; Tags: Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, geysers, mass spectroscopy

c. Beryllium Isotope Data

Sample Collection: Field work was conducted in November 2018 in the Upper Geyser Basin. Three sinter samples were collected from Castle Geyser and one sinter sample was collected from Solitary Geyser. At Castle Geyser, an effort was made to identify stable surfaces associated with the oldest exposed stratigraphic levels of sinter deposition, in order to target material emplaced during early stages of hydrothermal activity in the basin. At Solitary Geyser, material was collected from an exposure on the upper surface of a sinter deposit. All four sinter sample locations were selected to coincide with collection sites for material dated by radiocarbon methods, to enable a cross-comparison of results. Sinter was collected...

Categories: Data; Tags: Upper Geyser Basin, Yellowstone National Park, Yellowstone National Park, beryllium, geyser, All tags... radiometric dating, Fewer tags

h. Scanning Electron Microscopy (SEM) Data

Sample Analyses: Thin sections made at UC Berkeley were brought to the USGS, Menlo Park, CA and were coated with 25 nm carbon. Separately, untreated bulk centimeter-scale sinter sub-samples were affixed to aluminum stubs using amorphous carbon paste and coated with 10 nm Au-Pd. Both types of samples were analyzed at the USGS in Menlo Park, CA in a Tescan VEGA3 Scanning Electron Microscope (SEM) equipped with an Oxford 50 mm2 X-MaxN energy dispersive spectrometer. Stub-mount sub-samples were imaged with secondary electrons and thin sections were imaged with backscatter electrons. Energy dispersive X-ray spectroscopy (EDS) analyses and images were collected with an accelerating voltage of 15 kV and a working distance...