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The urbanized area of downtown Menlo Park is subject to persistent flooding and sediment deposition by San Francisquito Creek in South San Francisco Bay. To mitigate these events, a suite of cores was collected in 2002 at the mouth of the creek to determine sediment depositional rates on the delta. One of those cores (721-1) was selected for microbiological (pollen, diatoms, and foraminifera) and geochemical analyses to reconstruct a depositional record over the past two millennia. This data release provides radiocarbon dates, census counts of benthic foraminifera, diatoms, and palynomorphs, and the measurement of anthropogenic metals and other elements in sediments from this core.
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This part of the release provides an updated georeferenced catalog of limestone boulders and cobbles pertaining to extreme waves on Anegada, a low Caribbean island perched south of the Puerto Rico Trench. Tabulated are 660 limestone clasts, along with clast dimensions and long-axis trend in many instances. Fewer than one-fifth of the clasts were reported previously in https://doi.org/10.1007/s11069-011-9725-8 and https://doi.org/10.1130/GES01356.1. Most were surveyed in 2017.
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This data release provides geochemical, sedimentological, and geochronological data from interbedded fluvial and marsh deposits and radiocarbon dates of the section spanning the last 1500 years from the Pallett Creek paleoseismic site, California. The samples were collected to support paleoenvironmental reconstruction of the site and refine several previous investigations of paleoearthquakes along the San Andreas Fault (Sieh, 1978; Sieh, 1984; Sieh et al., 1989; Biasi and Weldon, 1994; Scharer et al., 2011). Geochemical and sedimentological data include grain size, magnetic susceptibility, dry bulk density, percent total organic matter, and percent total carbonate at contiguous 1 cm spacing and carbon (total C)...
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This part of the data release lists 18 localities where the shells of the tiger lucine Codakia orbicularis, a large marine bivalve, have been found on Anegada. Typically the shells were encountered a few tens of centimeters below ground in pits dug into sand. Most of the examples listed in the dataset were previously reported in https://doi.org/10.1130/GES01356.l -- field occurrences described p. 322, provenance interpreted p. 324, discordant radiocarbon ages discussed p. 324, and examples illustrated and mapped in Figure A9. The radiocarbon ages from lucines tabulated in this data set range across six radiocarbon centuries.
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This release provides inventories of georeferenced evidence pertaining to extreme waves on Anegada, a low Caribbean island perched south of the Puerto Rico Trench: CORAL BOULDERS AND COBBLES -- Derived offshore, found inland. Boulder star coral Orbicella franksii (37 localities), brain coral Pseudodiploria strigosa (171), elkhorn coral Acropora palmata (36), mustard hill coral Porites astreoides (29). LIMESTONE BOULDERS AND COBBLES -- Derived and found onshore (633). MOLLUSCAN SHELLS -- Queen conch Aliger gigas, discarded by precolonial fishers (12 onshore heaps) and by modern fishers (40 offshore heaps); individual conch shells deposited inland by precolonial sea flood (59); tiger lucine Codakia orbicularis, also...
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This dataset holds data associated with the stratigraphic descriptions and grain size analyses and the radiocarbon age dating for the journal article "Stratigraphy and eruption history of maars in the Clear Lake Volcanic Field, California"
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This data release includes geochronological data for the Airport East trench site (40.795359°, -111.950438°) on the Taylorsville fault of the West Valley fault zone (WVFZ). The WVFZ comprises intrabasin faults in the hanging wall of the Wasatch fault zone in the northern part of Salt Lake Valley, Utah. Samples for radiocarbon and luminescence dating were collected from two paleoseismic trenches in August–September 2015. Laboratory data include four optically stimulated luminescence ages and 14 radiocarbon ages for charcoal extracted from bulk sediment samples. This database has been approved for release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially...
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Charcoal counts and radiocarbon dates from four sediment cores collected in Great Dismal Swamp in 2017 and 2018 were incorporated into a synthesis of charcoal records from northern hemisphere peatlands (Sims et al., in review). Macroscopic charcoal was counted in three size classes: 125-250 micrometers, and 250-500 micrometers, and >500 micrometers. Uncalibrated radiocarbon dates were obtained and provided for use in development of age models for analyses by Sims et al., in review).
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This part of the data release provides an updated georeferenced list of radiocarbon ages pertaining to evidence for a catastrophic precolonial sea flood on Anegada, a low Caribbean island perched south of the Puerto Rico Trench. The list contains 64 ages measured on carbonate materials and 3 ages measured on plant fragments. Among the total of 67 ages, 43 are among the 47 ages previously tabulated on page 318 of https://doi.org/10.1130/GES01356.l. The 67 ages exclude those from previous work on deposits attributable to the 1755 Lisbon tsunami (https://doi.org/10.1007/s11069-010-9622-6). Among the 67 ages listed, the 24 ages previously unreported were measured mainly on samples collected in 2017. The main material...
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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...
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In the past century, eruptions of Steamboat Geyser in Yellowstone’s Norris Geyser Basin were mainly clustered in three episodes: between 1961 and 1969, between 1982 and 1984, and in a sequence of eruptions that began in 2018 (Reed et al., 2021) and resulted in extensive damage to, and mortality of the surrounding trees. To characterize tree response to geyser activity over time, and the response of geyser activity to climate variability, aerial and ground imagery were analyzed to document changes in tree coverage around the geyser since 1954. Twenty samples of silicified tree remnants were collected from near the geyser vent for radiocarbon (14C) dating to determine if trees grew during periods when the geyser was...
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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...
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This part of the release provides an georeferenced list on the most conspicuous of the onshore heaps of harvested conch shells on Anegada, a low Caribbean island perched south of the Puerto Rico Trench. The list locates 12 conch heaps noted in 2017 in the island's East End: Also listed are radiocarbon ages measured on shells from six of the heaps.
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This data release provides radiocarbon data for burned plant material collected from deposits following two wildfires in southern California. For the 2020 Bobcat Fire we collected deposits in five stream channels within the Pallett Creek drainage in 2021. For the 2013 Grand Fire near Frazier Mountain, we sampled from two shallow pits excavated into alluvium deposited in 2014. The types of taxa present at each sample location were identified and radiocarbon samples were selected based on the types of material present. This report should be used as the supplementary materials for any publication(s) that uses the radiocarbon dates or taxa identification reported herein.
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This data release includes data collected in the pursuit of identifying pre- and post-colonial riparian ecosystems found throughout Anne Arundel County, Maryland, USA. Two comma-delimited tables are included. The first documents pollen records at various depths identified within sediment samples taken throughout the county's floodplains. The other describes morphological information identifying tree species found buried in-situ throughout the county.
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Results are presented from Accelerator Mass Spectrometry (AMS) carbon-14 radiocarbon dating of carbonate rock samples collected from seep fields offshore the U.S. Mid- and South Atlantic in 2018 and 2019. Samples were collected as a fingerprint to past hydrocarbon seep activity, fluid source, and depositional environment.
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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.
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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).
map background search result map search result map Geochemical analysis of authigenic carbonates and chemosynthetic mussels at Atlantic Margin seeps (ver. 2.0, March 2019) Radiocarbon Dating Radiocarbon dating of deep-sea black corals collected off the southeastern United States Geophysical properties, geochronologic, and geochemical data of sediment cores collected from San Pablo Bay, California, October 17-20, 2016 Accelerator Mass Spectrometry (AMS) 14C radiocarbon analysis of authigenic carbonates collected offshore the U.S. Mid- and South Atlantic Geochronological data for the Airport East trench site, West Valley fault zone, Salt Lake County, Utah Clear Lake Volcanic Field maar deposit grain size distributions, Inman grain size statistics, and radiocarbon ages Charcoal data from four sites in Great Dismal Swamp National Wildlife Refuge - August 2022 Radiocarbon dating of silicified wood from around Steamboat Geyser in Norris Geyser Basin, Yellowstone National Park, 2021-2022 Radiocarbon age dating of biological material from cores collected off central California in 1999, 2006, and 2019 Radiocarbon measurements, census counts of benthic foraminifera, diatoms, and palynomorphs, and geochemistry from core 721-1 obtained in 2002 off San Francisquito Creek in South San Francisco Bay Ecological and Dendrological Data Collected Across Anne Arundel County, Maryland in 2019 Field evidence noted in 2008 to 2023 that pertains to sea floods of the past millennium on Anegada, British Virgin Islands Onshore conch heaps noted in 2012 to 2018 that pertain to sea floods of the past 1,000 years on Anegada, British Virgin Islands Limestone boulders and cobbles noted 2009 to 2017 that pertain to sea floods of the past 1,000 years on Anegada, British Virgin Islands Strewn shells of a large marine bivalve noted 2008 to 2017 on Anegada, British Virgin Islands Radiocarbon ages measured 2011 to 2021 on corals, shells, and plant fragments pertaining to sea floods of the past 1,000 years on Anegada, British Virgin Islands Radiocarbon dates from the 2020 Bobcat Fire and 2013 Grand Fire, Western Transverse Ranges, California Sediment properties, charcoal counts, and radiocarbon dates from the Pallett Creek paleoseismic site, San Gabriel Mountains, California (ver. 2.0, February 2024) Radiocarbon Dating Geochronological data for the Airport East trench site, West Valley fault zone, Salt Lake County, Utah Onshore conch heaps noted in 2012 to 2018 that pertain to sea floods of the past 1,000 years on Anegada, British Virgin Islands Strewn shells of a large marine bivalve noted 2008 to 2017 on Anegada, British Virgin Islands Radiocarbon ages measured 2011 to 2021 on corals, shells, and plant fragments pertaining to sea floods of the past 1,000 years on Anegada, British Virgin Islands Limestone boulders and cobbles noted 2009 to 2017 that pertain to sea floods of the past 1,000 years on Anegada, British Virgin Islands Sediment properties, charcoal counts, and radiocarbon dates from the Pallett Creek paleoseismic site, San Gabriel Mountains, California (ver. 2.0, February 2024) Charcoal data from four sites in Great Dismal Swamp National Wildlife Refuge - August 2022 Radiocarbon measurements, census counts of benthic foraminifera, diatoms, and palynomorphs, and geochemistry from core 721-1 obtained in 2002 off San Francisquito Creek in South San Francisco Bay Clear Lake Volcanic Field maar deposit grain size distributions, Inman grain size statistics, and radiocarbon ages Ecological and Dendrological Data Collected Across Anne Arundel County, Maryland in 2019 Radiocarbon age dating of biological material from cores collected off central California in 1999, 2006, and 2019 Geochemical analysis of authigenic carbonates and chemosynthetic mussels at Atlantic Margin seeps (ver. 2.0, March 2019) Radiocarbon dates from the 2020 Bobcat Fire and 2013 Grand Fire, Western Transverse Ranges, California Accelerator Mass Spectrometry (AMS) 14C radiocarbon analysis of authigenic carbonates collected offshore the U.S. Mid- and South Atlantic Radiocarbon dating of deep-sea black corals collected off the southeastern United States