@booklet {hurwitz_silicified_2020,
	title = {Silicified wood from around Old Faithful Geyser, Yellowstone National Park: U.S. Geological Survey data release},
	year = {2020},
	note = {Type: dataset},
	publisher = {U.S. Geological Survey},
	abstract = {Radiocarbon dating of silicified wood was performed at the U.S. Geological Survey{\textquoteright}s Radiocarbon Laboratory in Denver, Colorado. All samples were chemically treated using the standard acid-base-acid (ABA) procedure before being combusted online in the presence of excess high-purity oxygen. Water and other contaminant gases were removed using cryogenic separation techniques, and the resulting purified CO2 gas was measured manometrically and converted to graphite using an iron catalyst and hydrogen reduction (Vogel et al., 1984). Graphite targets were then submitted for accelerator mass spectrometry 14C analysis at the National Ocean Sciences Accelerator Mass Spectrometry facility in Woods Hole, Massachusetts.

All 14C ages were calibrated using the IntCal13 dataset and CALIB 7.1html (Stuiver and Reimer, 1993; Reimer et al., 2013). Calibrated age ranges are presented in calibrated years before present (BP; 0 yr BP = 1950 A.D.), and uncertainties are given at the 95\% (2sigma) confidence level.

Select sub-samples of silicified wood were excised with a stainless-steel razor blade and massed into 4 x 6 mm tin capsules (Costech Analytical, Inc, USA). Stable carbon isotope (δ13C) analysis was conducted by continuous flow-isotope ratio mass spectrometry at the U.S. Geological Survey{\textquoteright}s Stable Isotope Laboratory in Denver, Colorado using a Carlo Erba NC1500 interfaced to a Micromass Optima mass spectrometer.  Isotopic data are reported in per mil notation after normalization to VPDB with USGS 40 (δ13C = -26.39 {\textperthousand}) and USGS 41A (δ13C = 36.55 {\textperthousand}).

This research was conducted under Yellowstone Research Permit YELL-SCI-8030.},
	doi = {10.5066/P9LEQ5HC},
	url = {https://www.sciencebase.gov/catalog/item/get/5eb9b5ba82ce25b5135d2718},
	author = {Hurwitz, Shaul and Peek, Sara E and Pigati, Jeff and Honke, Jeff and Damby, David E and Stricker, Craig A and King, John}
}
@article {hurwitz_yellowstones_2020,
	title = {Yellowstone{\textquoteright}s Old Faithful Geyser Shut Down by a Severe Thirteenth Century Drought},
	journal = {Geophysical Research Letters},
	volume = {47},
	number = {20},
	year = {2020},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020GL089871},
	month = {10/2020},
	pages = {e2020GL089871},
	abstract = {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{\textendash}1362 CE) is coincident with a series of severe multidecadal regional droughts toward the end of the Medieval Climate Anomaly, prior to the onset of the Little Ice Age. Climate models project increasingly severe droughts by mid-21st century, suggesting that geyser eruptions could become less frequent or completely cease.},
	keywords = {drought, Medieval Climate Anomaly, mineralization, Old Faithful Geyser, radiocarbon, Yellowstone},
	issn = {1944-8007},
	doi = {10.1029/2020GL089871},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GL089871},
	author = {Hurwitz, Shaul and King, John C. and Pederson, Gregory T. and Martin, Justin T. and Damby, David E. and Manga, Michael and Hungerford, Jefferson D. G. and Peek, Sara}
}
