This dataset contains 40Ar/39Ar data and ages for volcanic rocks in the Mushroom Rock region, northeastern California

This dataset contains 40Ar/39Ar data and ages for volcanic rocks in the Mushroom Rock region, northeastern California

This part of the data release is a spreadsheet including radiocarbon sample information and calibrated ages of sediment cores collected in 2014 from the northern flank of Monterey Canyon, offshore California. It is one of five files in this U.S. Geological Survey data release that include data from a set of sediment cores acquired from the continental slope, north of Monterey Canyon, offshore central California. Vibracores and push cores were collected with the Monterey Bay Aquarium Research Institute’s (MBARI’s) remotely operated vehicle (ROV) Doc Ricketts in 2014 (USGS cruise ID 2014-615-FA). One spreadsheet (NorthernFlankMontereyCanyonCores_Info.xlsx) contains core name, location, and length. One spreadsheet (NorthernFlankMontereyCanyonCores_MSCLdata.xlsx) contains Multi-Sensor Core Logger P-wave velocity and gamma-ray density whole-core logs of vibracores. One zipped folder of .bmp files (NorthernFlankMontereyCanyonCores_Photos.zip) contains continuous core photographs of the archive half of each vibracore. One spreadsheet (NorthernFlankMontereyCanyonCores_Radiocarbon.xlsx) contains radiocarbon sample information, results, and calibrated ages. One .pdf file (NorthernFlankMontereyCanyonCores_Figures.pdf) contains combined displays of data for each vibracore, including graphic diagram descriptive logs. This particular metadata file describes the information contained in the file NorthernFlankMontereyCanyonCores_Radiocarbon.xlsx. All vibracores are archived by the U.S. Geological Survey Pacific Coastal and Marine Science Center. Other remaining core material, if available, is archived at MBARI.

This part of the data release is a spreadsheet including radiocarbon sample information and calibrated ages of sediment cores collected in 2014 from the northern flank of Monterey Canyon, offshore California. It is one of five files in this U.S. Geological Survey data release that include data from a set of sediment cores acquired from the continental slope, north of Monterey Canyon, offshore central California. Vibracores and push cores were collected with the Monterey Bay Aquarium Research Institute’s (MBARI’s) remotely operated vehicle (ROV) Doc Ricketts in 2014 (USGS cruise ID 2014-615-FA). One spreadsheet (NorthernFlankMontereyCanyonCores_Info.xlsx) contains core name, location, and length. One spreadsheet (NorthernFlankMontereyCanyonCores_MSCLdata.xlsx) contains Multi-Sensor Core Logger P-wave velocity and gamma-ray density whole-core logs of vibracores. One zipped folder of .bmp files (NorthernFlankMontereyCanyonCores_Photos.zip) contains continuous core photographs of the archive half of each vibracore. One spreadsheet (NorthernFlankMontereyCanyonCores_Radiocarbon.xlsx) contains radiocarbon sample information, results, and calibrated ages. One .pdf file (NorthernFlankMontereyCanyonCores_Figures.pdf) contains combined displays of data for each vibracore, including graphic diagram descriptive logs. This particular metadata file describes the information contained in the file NorthernFlankMontereyCanyonCores_Radiocarbon.xlsx. All vibracores are archived by the U.S. Geological Survey Pacific Coastal and Marine Science Center. Other remaining core material, if available, is archived at MBARI.

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) to nitrogen (total N) ratios and charcoal counts every 4 cm from a 6.2 m section at the Pallett Creek paleoseismic site (34.4557°, -117.8872°). The data release also includes new and previously published radiocarbon datasets and associated depths to facilitate inter-study comparison. These datasets include: (1) New accelerator mass spectrometry (AMS) radiocarbon dates, completed in 2021 and 2022, targeting layers with few or conflicting dates in previous studies at the Pallett Creek paleoseismic site. For these samples, the types of taxa present in selected layers was determined. (2) AMS dates originally reported in Scharer et al. (2011) are included with amended d13C fractionation corrections and are assigned depths to the 6.2 m section at the Pallett Creek paleoseismic site. (3) Depths are assigned for conventional radiocarbon dates previously reported in Sieh (1978), Sieh et al. (1984), Sieh et al. (1989) and Biasi and Weldon (1994). The depth estimates enable use of the original studies with the newer stratigraphic and age data provided in the data release. (4) New radiocarbon dates from the same alluvial surface as the Pallett Creek paleoseismic site that are exposed ~1 km upstream (34.4536°, -117.8980°). This report should be used as the supplementary materials for any publication(s) that uses the sedimentologic and geochemical data or taxa identification or radiocarbon dates and depths reported herein. Revision 2.0 by Katherine M. Scharer on February 6, 2024. To review the changes that were made see 'Versioning.txt' file in the Attached Files section on the data release landing page.

This geologic map database is a reproduction of U.S. Geological Survey Miscellaneous Investigations Map I–2362: “Geologic Map and Structure Sections of the Clear Lake Volcanics, Northern California” (Hearn, Donnelly-Nolan, and Goff, 1995). The database consists of a geologic map, three structural cross sections and a table of petrographic data for each map unit by mineral type, abundance, and size. The Clear Lake Volcanics are in the California Coast Ranges about 150 km north of San Francisco. This Quaternary volcanic field has erupted intermittently since 2.1 million years ago. This volcanic field is considered a high-threat volcanic system (Ewert and others, 2005). The adjacent Geysers geothermal field, the largest power-producing geothermal field in the world, is powered by the magmatic heat source for the volcanic field. The geology of parts of the area underlain by the Cache Formation is based on mapping by Rymer (1981); the geology of parts of the areas underlain by the Sonoma Volcanics, Franciscan assemblage, and Great Valley sequence is based on mapping by McLaughlin (1978). Volcanic compositional map units are basalt, basaltic andesite, andesite, dacite, rhyodacite, and rhyolite, based on SiO2 content. Most ages are potassium-argon (K/Ar) ages determined for whole-rock samples and mineral separates by Donnelly-Nolan and others (1981), unless otherwise noted. A few ages are carbon-14 ages or were estimated from geologic relationships. Magnetic polarities are from Mankinen and others (1978; 1981) or were determined in the field by B.C. Hearn, Jr., using a portable fluxgate magnetometer. Thickness for most units is estimated from topographic relief except where drill-hole data were available. This database does not reproduce all elements of the original publication. Omissions include the chart and figures showing erupted volumes of different lava types through time, and the chart and diagram for the correlation of map units. Users of this database are highly encouraged to cross reference this database with the original publication.

This dataset contains 40Ar/39Ar ages from the Mushroom Rock region, northeastern California, and can be found in Table 3 in the related manuscript.

This dataset contains 40Ar/39Ar ages from the Mushroom Rock region, northeastern California, and can be found in Table 3 in the related manuscript.

The data herein are geochemical (from X-Ray fluorescence spectrometry), grain size (percent clay, silt, sand), lithological (loss on ignition data), bathymetric, reconstructed IVT, and radioactive isotopes (14-C, 210-Pb, 226-Ra, and 137-Cs). These data were collected from sediments from Leonard Lake, Mendocino County, California, USA starting in 2014. Together, these data provide evidence for a record of extreme precipitation going back three millennia, showing regional pluvial and drought cycles.

Recalculated geochemistry data for bedrock volcanic samples listed in Table 1 Volcanic Rock Samples. Samples collected from the Mushroom Rock region, northeastern California.