Filters: Tags: carbon-14 analysis (X)16 results (674ms)
Dissolved organic carbon and nitrogen release from boreal Holocene permafrost and seasonally frozen soils of Alaska
Permafrost (perennially frozen) and active-layer (seasonally thawed) soils varying in soil carbon (C) and nitrogen (N) content and radiocarbon age were collected from three sites in interior Alaska to determine potential release of dissolved organic carbon (DOC), total dissolved N (TDN), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (DIN) upon thaw. Soil cores were cut into 15 cm thick sections, and deep active-layer (15-30 cm above the permafrost boundary) and shallow permafrost (15-30 cm below the permafrost boundary) sections were thawed and leached with deionized water. Soil leachates were analyzed for DOC, TDN, nitrate (NO3-), and ammonium (NH4+) concentrations, dissolved organic matter...
This portion of the data release presents radiocarbon age data from 66 samples collected from Anahola Valley (Kaua'i), Kahana Valley (O'ahu), and Pololu Valley (Hawai'i). Sample ages were determined by the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. The data are provided in a comma-delimited spreadsheet (.csv).
Results of radiocarbon dating of deep-sea (500 m to 700 m) black corals are presented. These corals were collected off the southeastern United States as part of the Southeastern United States Deep-Sea Corals (SEADESC) Initiative.
Chronology and time-series geochemistry data of a coral core collected from Olowalu, West Maui, Hawaii. The chronology is based on density banding, radiocarbon bomb-curve, and uranium thorium dating techniques. The geochemistry time-series data contains major and minor elements over the length of the coral life span, as measured from laser ablation inductively coupled mass spectrometry (LA-ICP-MS).
Radiocarbon dates, charcoal, and polycyclic aromatic hydrocarbon (PAH) data from Great Dismal Swamp Sites GDS-519 and GDS-520
Sediment cores were collected in Great Dismal Swamp National Wildlife Refuge in November, 2017 to advance understanding of climate- and land-management driven changes in vegetation, hydrology, and fire regimes. Radiocarbon dates were obtained from samples in two cores (GDS-519-3-21-2017 and GDS-520-3-21-2017) to generate age models for the cores. Bulk sediment samples, charcoal, plant macrofossils, and pollen residue were selected at the USGS in Reston, Virginia and submitted to Beta Analytic, Inc. and the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) laboratories for radiocarbon dating. Those laboratories provided both radiocarbon ages and stable carbon isotope (delta 13C) results, which can be...
Geophysical properties, geochronologic, and geochemical data of sediment cores collected from San Pablo Bay, California, October 17-20, 2016
Geophysical properties (P-wave velocity, gamma ray density, and magnetic susceptibility), geochronologic (radiocarbon, excess Lead-210, and Cesium-137), and geochemical data (organic carbon content and 60 element contents) are reported for select vibracores collected aboard the S/V Retriever October 17-20, 2016 in San Pablo Bay, California. Geophysical properties were measured with a Geotek Multi-Sensor Core Logger (MSCL). Radiocarbon was measured by accelerator mass spectrometry (AMS). Excess Lead-210 and Cesium-137 activities were measured by gamma-ray counting in a high purity, low background germanium well detector (HPGe). Total organic carbon was measured in bulk sediment. Element contents were determined on...
This collection contains a comprehensive inventory of geologic (coral, rock, and sediment) cores and samples collected, analyzed, published, and/or archived by, or in collaboration with, the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC). The SPCMSC Core and Sediment Sample Database includes geologic cores and samples collected beginning in the 1970s to present day, from study sites across the world. This database can be accessed through the CoreViewer 3.0 ArcOnline web mapping application, linked below. A copy of the data can also be downloaded from the web mapping application and the metadata is accessible through a link in the header of the application. The database captures...
Time-series of sediment chemistry, including organic biomarker composition and bulk inorganic geochemical analytes, from samples collected over a one-year period in a sediment trap. The sediment traps were deployed at a depth between 603 m to 1318 m, and they were programmed to rotate a 250 mL sample bottle at 30 d intervals, delivering 12 samples during the 1-year deployment between August 2012 and June 2013. In addition, dissolved water column nutrient concentrations and water column trace element particulate concentrations were collected in Baltimore Canyon on the U.S. Mid-Atlantic Bight (MAB).
Radiocarbon dating of silicified wood was performed at the U.S. Geological Survey’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...
Geochemistry time series and growth parameters from Tutuila, American Samoa coral record (ver. 2.0, June 2021)
Geochemical analysis (including age-corrected radiocarbon stable isotopes, and elemental composition) and growth parameters (including calcification rate, density, and extension information) were measured from a coral core collected from a reef off the southern side of Tutuila, American Samoa. The core was collected near Matautuloa Point on 8 April 2012 in collaboration with the Ecosystem Sciences Division, Pacific Islands Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA), Honolulu, HI.
Geochemical analysis of authigenic carbonates and chemosynthetic mussels at Atlantic Margin seeps (ver. 2.0, March 2019)
First release: 2016 Revised: 2019 Isotopic analyses of authigenic carbonates and methanotrophic deep-sea mussels, Bathymodiolus sp., was performed on samples collected from seep fields in the Baltimore and Norfolk Canyons on the north Atlantic margin. Samples were collected using remotely operated underwater vehicles (ROVs) during three different research cruises in 2012, 2013, and 2015. Analyses were performed by several different laboratories, and the results are presented in spreadsheet format.
This database contains a comprehensive inventory of geologic (coral, rock, and sediment) cores and samples collected, analyzed, published, and/or archived by, or in collaboration with, the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC). The SPCMSC Core and Sediment Sample Database includes geologic cores and samples collected beginning in the 1970s to present day, from study sites across the world. This database can be accessed through the CoreViewer 3.0 ArcOnline web mapping application, linked below. A copy of the data can also be downloaded from the web mapping application and the metadata is accessible through a link in the header of the application, as well as, through...
Silicified wood samples were vacuum impregnated with epoxy, sectioned, and sputter coated with 10 nm Au/Pd at the U.S. Geological Survey, Menlo Park, CA. Samples were imaged in a Tescan VEGA3 Scanning Electron Microscope (SEM) equipped with an Oxford 150 mm2 X-MaxN large area energy dispersive spectrometer at the U.S. Geological Survey, Menlo Park, CA. Backscatter (BSE) images were collected with an accelerating voltage (HV) of 30 kV and a working distance (WD) of ~15 mm. Magnification is indicated on individual images. The data files for Scanning Electron Microsocopy (SEM) contain representative SEM-BSE images of samples OFL101 and OFL103-2. This research was conducted under Yellowstone Research Permit YELL-SCI-8030.
Old Faithful Geyser in the Upper Geyser Basin of Yellowstone National Park is one of the best studied geysers in the world. Under research permit YELL-SCI-8030, samples from 13 silicified tree remnants were collected adjacent to the Old Faithful Geyser cone in April and November 2019. The silicified wood samples were dated using the radiocarbon (14C) method and were analyzed by scanning electron microscope (SEM) to determine the extent of wood silicification. This study was conducted in order to provide new information on the geyser’s past decadal to centennial eruptive activity. Understanding Old Faithful’s past could provide a baseline for understanding future changes in its eruption intervals.
Census counts of benthic foraminifera, environmental parameters (temperature, salinity, and oxygen concentration), and radiocarbon measurements from cores obtained under and near a whale-fall off western Vancouver Island, British Columbia, Canada
This data release provides census counts of benthic foraminifera (in percent for the total fauna and as raw counts for just the living specimens) as well as environmental parameters (temperature, salinity, and oxygen concentration) at the sampling sites, and radiocarbon measurements from selected push core samples obtained under and near a whale-fall off western Vancouver Island, British Columbia, Canada.
Data compiled from stratigraphic and tree-ring studies of late Holocene earthquakes and tsunamis at Copalis River, Grays Harbor, Willapa Bay, and Columbia River, Washington and Oregon
This dataset consists of tabular information from coastal studies of earthquake and tsunami history along a central part of the Cascadia Subduction Zone. The study area encompasses four estuaries along the Pacific coast of southern Washington and northernmost Oregon. Nearly all the field work took place between 1986 and 1998. Data tables, 18 in all, archive mostly georeferenced information about stratigraphy, radiocarbon ages, and trees dead and living. Some of this data was interpreted in reports published between 1987 and 2005, but most of it was previously unavailable. An accompanying guide, with hyperlinks to the data tables, explains the data tables more thoroughly than does the metadata. Contributors include...