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Filters: Tags: {"type":"Harvest Set"} (X) > partyWithName: Lesleigh Anderson (X) > partyWithName: U.S. Geological Survey - ScienceBase (X)

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Holocene sediments at Emerald Lake in central Utah (3090 m a.s.l), document the paleohydroclimatic history of the western Upper Colorado River headwater region. Multi-proxy analyses of sediment composition, mineralogy, and stable isotopes of carbonate (d18O and d13C) show changes in effective moisture for the past ca. 10,000 years at millennial to decadal timescales. Emerald Lake originated as a shallow closed-basin cirque pond during the early Holocene. By ca. 7000 cal yr BP, higher lake levels and carbonate d18O values indicate rising effective moisture and higher proportions of summer precipitation continued at least until ca. 5500 cal yr BP when a landslide entered the lake margin. Between ca. 4500 and 2400...
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Andrews Meadow in the Loch Vale watershed, Rocky Mountain National Park. Sample Collection: Englemann spruce (Picea engelmannii) living on slopes surrounding and at the edge of Andrews meadow (Latitude 40˚ 17’ 24” N, Longitude 105˚ 40’ 01” W NAD83). At the time of collection, the climate-sensitive upland P. engelmannii trees were growing on well-drained slopes above the meadow. Seventeen trees, two cores per tree when possible, were collected using a 5mm-diameter increment borer. During sample collection, diameter at breast height (DBH) was also measured. These cores were processed following standard dendrochronological methods. The annual (TW) and earlywood (EW) ring-widths of each core were measured to 0.001mm...
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The current state of permafrost in Alaska and meaningful expectations for its future evolution are informed by long-term perspectives on previous permafrost degradation. Thermokarst processes in permafrost landscapes often lead to widespread lake formation and the spatial and temporal evolution of thermokarst lake landscapes reflects the combined effects of climate, ground conditions, vegetation, and fire. This study provides detailed analyses of thermokarst lake sediments of Holocene age from the southern loess uplands of the Yukon Flats; including bathymetry and sediment core analyses across a water depth transect. The sediment core results, dated by radiocarbon and 210Pb, indicate the onset of finely laminated...
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During recent decades, lake levels in the Yukon Flats region of interior Alaska have fluctuated dramatically. However, prior to recorded observations, no data are available to indicate if similar or more extreme variations occurred during past centuries and millennia. This study explores the history of Yukon Flats lake origins and lake levels for the past approximately 5,500 years from sediment analyses guided by previous work on permafrost extent, thermokarst, and modern isotope hydrology. Sediments dated by 210Pb and AMS radiocarbon indicate stable chronologies following initial lake initiation. Subsequent lithology is autochthonous, and oxygen isotope ratios of endogenic carbonate reflect lake level change at...
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The stable hydrogen (delta 2H) and oxygen (delta 18O) isotopic compositions of more than 4,300 weekly composite samples of precipitation from thirteen National Atmospheric Deposition Program (NADP) sites (CO02, CO08, CO09, CO10, CO21, CO89, CO91, CO92, CO93, CO96, CO97, CO98, and UT09) in Colorado and Utah were analyzed on archived samples obtained from NADP over various time periods between January 2001 and October 2022. The samples are from the NADP National Trends Network (NTN) with weekly sample frequency. Data on site location, collection begin and end dates, sample volume and precipitation amounts were furnished from publicly-available NADP sources and were not evaluated for accuracy. Measured values range...
    map background search result map search result map Data release for Lake levels in a discontinuous permafrost landscape: Late Holocene variations inferred from sediment oxygen isotopes, Yukon Flats, Alaska Data Release for "Holocene thermokarst lake dynamics in northern Interior Alaska: the interplay of climate, fire, and subsurface hydrology" Data Release for Holocene Paleohydrology from alpine lake sediment, Emerald Lake, Wasatch Plateau of central Utah, USA Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Colorado and Utah National Atmospheric Deposition Program (NADP) sites Tree-ring widths of Picea engelmannii at Andrews Meadow, Rocky Mountain National Park Tree-ring widths of Picea engelmannii at Andrews Meadow, Rocky Mountain National Park Data Release for Holocene Paleohydrology from alpine lake sediment, Emerald Lake, Wasatch Plateau of central Utah, USA Data release for Lake levels in a discontinuous permafrost landscape: Late Holocene variations inferred from sediment oxygen isotopes, Yukon Flats, Alaska Stable hydrogen and oxygen isotopic compositions of precipitation samples from selected Colorado and Utah National Atmospheric Deposition Program (NADP) sites Data Release for "Holocene thermokarst lake dynamics in northern Interior Alaska: the interplay of climate, fire, and subsurface hydrology"