Research Chemist
Email:
ddamby@usgs.gov
Office Phone:
650-439-2661
ORCID:
0000-0002-3238-3961
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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,...
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Sample Analyses: Thin sections made at UC Berkeley were brought to the USGS, Menlo Park, CA and were coated with 25 nm carbon. 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. 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 of 15 mm. Database Contents: The data files for “Energy Dispersive X-ray Spectroscopy (EDS) Data” contain representative element spectra analyses of samples UGB-TD-28, -30, -31, -32, -33, -36.
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To characterize eruption activity of the iconic Old Faithful Geyser in Yellowstone National Park over past centuries, we obtained 41 new radiocarbon dates of mineralized wood preserved in the mound of silica that precipitated from erupted waters. Trees do not grow on active geyser mounds, implying that trees grew on the Old Faithful Geyser mound during a protracted period of eruption quiescence. Rooted stumps and root crowns located on higher parts of the mound are evidence that at the time of tree growth, the geyser mound closely resembled its current appearance. The range of calibrated radiocarbon dates (1233–1362 CE) is coincident with a series of severe multidecadal regional droughts toward the end of the Medieval...
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A limited suite of samples for the 2020–2023 Kīlauea eruptions within Kaluapele (the summit caldera) were collected by the U.S. Geological Survey’s Hawaiian Volcano Observatory (HVO) field teams from within a publicly closed area of Hawai‘i Volcanoes National Park in cooperation with the National Park Service. This data release presents sample metadata, whole rock ED-XRF, whole rock WD-XRF, whole rock LA-ICP-MS, glass EPMA, glass LA-ICP-MS, leachate, and isotope data for these samples.
Categories: Data;
Tags: Geochemistry,
Kīlauea, Island of Hawai‘i, Halema‘uma‘u, Kaluapele,
USGS Science Data Catalog (SDC),
Volcanology,
basalt, glass, volcano, eruption, chemistry, All tags...
biota, Fewer tags
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Methods Total element abundances in the bulk tephra samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) following a 4-acid digest at the USGS analytical laboratories in Denver, CO. Briefly, the tephra samples were digested using a mixture of hydrochloric, nitric, perchloric and hydrofluoric acids at low temperature following the methods of Crock and otheres (1983). The resultant fluid was aspirated into a 42-element ICP-MS for analysis following the analytical procedure of Briggs and Meier (2002). USGS geochemical reference materials BIR-1, BCR-1, and BHVO-1 were analyzed before and after Kilauea tephra samples for data quality control. Kīlauea sample A7-0641 was analyzed as an analytical...
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