This dataset includes computed tomography (CT) scans of sediment cores collected from Cargill Marsh, South San Francisco Bay, California on June 21, 2022, and December 14, 2023. The cores were collected with hand driven push cores to assess sediment accumulation on the marsh. CT images are provided in the original 16-bit grayscale TIFF format.

This dataset includes computed tomography (CT) scans of sediment cores collected from Cargill Marsh, South San Francisco Bay, California on June 21, 2022, and December 14, 2023. The cores were collected with hand driven push cores to assess sediment accumulation on the marsh. CT images are provided in the original 16-bit grayscale TIFF format.

This dataset presents core information such as core IDs, core lengths, depth intervals, and locations from sediment cores collected from Cargill Marsh, South San Francisco Bay, California on June 21, 2022, and December 14, 2023. The cores were collected with hand driven push cores to assess sediment accumulation on the marsh.

This dataset includes photographs (linescan images) of sediment cores collected from Cargill Marsh, South San Francisco Bay, California on June 21, 2022, and December 14, 2023. The cores were collected with hand driven push cores to assess sediment accumulation on the marsh.

This dataset includes photographs (linescan images) of sediment cores collected from Cargill Marsh, South San Francisco Bay, California on June 21, 2022, and December 14, 2023. The cores were collected with hand driven push cores to assess sediment accumulation on the marsh.

Sediment samples were collected from Los Padres reservoir in the Carmel River watershed, central California coast, between July 11 and 17, 2017, using a CME-45 barge-mounted drill rig, to characterize sedimentary properties in the reservoir deposits following the Soberanes Fire of 2016 and high river flows in winter 2017. Borehole samples were recovered using direct push coring with an Osterberg piston sampler operated by Taber Drilling Company of Sacramento, California, and overseen by AECOM, Inc. Sediment was recovered using a split-barrel sampler and a rotary drill bit was added to the sampler where needed to penetrate coarse sediment. Samples from three boreholes are described in this data release: two sampled at multiple sediment depths (B2 and B7) and a third (B4) from which only the topmost sample is included. Each borehole was drilled to the depth of apparent pre-dam alluvium or bedrock. Alternate sections were described and sampled; every second section was discarded without examination. Geochemical data are reported for sediment cores. Data include short-lived cosmogenic and natural radionuclide activities for Lead-210; Radium-226, Cesium-137, Thorium-234, and excess Lead-210. The USGS gratefully acknowledges collaboration with B. Kozlowicz of AECOM, Inc., in the collection of these data. Purpose: Laboratory measurements of natural lead, radium, cesium, and thorium isotope concentrations in Los Padres reservoir, Carmel River watershed, California, to characterize post-fire sedimentation history.

Sediment samples were collected from Los Padres reservoir in the Carmel River watershed, central California coast, between July 11 and 17, 2017, using a CME-45 barge-mounted drill rig, to characterize sedimentary properties in the reservoir deposits following the Soberanes Fire of 2016 and high river flows in winter 2017. Borehole samples were recovered using direct push coring with an Osterberg piston sampler operated by Taber Drilling Company of Sacramento, California, and overseen by AECOM, Inc. Sediment was recovered using a split-barrel sampler and a rotary drill bit was added to the sampler where needed to penetrate coarse sediment. Samples from three boreholes are described in this data release: two sampled at multiple sediment depths (B2 and B7) and a third (B4) from which only the topmost sample is included. Each borehole was drilled to the depth of apparent pre-dam alluvium or bedrock. Alternate sections were described and sampled; every second section was discarded without examination. Geochemical data are reported for sediment cores. Data include short-lived cosmogenic and natural radionuclide activities for Lead-210; Radium-226, Cesium-137, Thorium-234, and excess Lead-210. The USGS gratefully acknowledges collaboration with B. Kozlowicz of AECOM, Inc., in the collection of these data. Purpose: Laboratory measurements of natural lead, radium, cesium, and thorium isotope concentrations in Los Padres reservoir, Carmel River watershed, California, to characterize post-fire sedimentation history.

This data release contains data from cores collected in marshes and in sediments under invasive Brazilian waterweed (Egeria densa Planchon) in the Sacramento-San Joaquin Delta of California during the spring of 2018. Data are provided in two text files in comma separated columns. The first Core_Sites_Details.txt contains core site location, collection dates, and naming information. The second file, Core_Section_Analyses.txt contains % organic carbon, % inorganic sediment, bulk density data for each 2-cm section of six peat cores collected in marshes and six sediment cores collected under patches of Brazilian waterweed. Additionally, the second file contains the radioisotope values (137Cs and 210Pb) for each of the cores. Cores were collected at three Delta study sites: Lindsey Slough, Mokelumne River, and Middle River in the Delta.

Sediment cores were collected from three sites within the Plum Island Ecosystems Long-Term Ecological Research (PIE-LTER) domain in Massachusetts to obtain estimates of long-term marsh decomposition and evaluate shifts in the composition and reactivity of sediment organic carbon in disturbed marsh environments. Paired sediment cores were collected from three sites on the marsh platform and from three ponds; these cores were about 100 and 50 centimeters in length, respectively. The marsh sites had similar elevations, at about 1.41 to 1.51 meters relative to the North American Vertical Datum of 1988, and similar salt marsh grass communities, dominated by Spartina patens, S. alterniflora, and Distichlis spicata. Permanently inundated ponds within each site had comparable depths (0.24–0.30 meters) but varied in size (between 643 and 7,149 square meters; Spivak et al., 2017, 2018). The U.S. Geological Survey analyzed radioisotope concentrations for lead-210, radium-226, cesium-127, and beryllium-7 from six marsh cores and three pond cores to develop an age model for each core. This data release includes calculated percent dry bulk density and raw radioisotope data for these cores. Spivak, A.C., Gosselin, K., Howard, E., Mariotti, G., Forbrich, I., Stanley, R., and Sylva, S.P., 2017, Shallow ponds are heterogeneous habitats within a temperate salt marsh ecosystem: Journal of Geophysical Research-Biogeosciences, 122(6), 1371-1384. Spivak, A. C., Gosselin, K. M., and Sylva, S.P., 2018, Shallow ponds are biogeochemically distinct habitats in salt marsh ecosystems: Limnology and Oceanography, 63(4), 1622-1642.

Sediment cores were collected from three sites within the Plum Island Ecosystems Long-Term Ecological Research (PIE-LTER) domain in Massachusetts to obtain estimates of long-term marsh decomposition and evaluate shifts in the composition and reactivity of sediment organic carbon in disturbed marsh environments. Paired sediment cores were collected from three sites on the marsh platform and from three ponds; these cores were about 100 and 50 centimeters in length, respectively. The marsh sites had similar elevations, at about 1.41 to 1.51 meters relative to the North American Vertical Datum of 1988, and similar salt marsh grass communities, dominated by Spartina patens, S. alterniflora, and Distichlis spicata. Permanently inundated ponds within each site had comparable depths (0.24–0.30 meters) but varied in size (between 643 and 7,149 square meters; Spivak et al., 2017, 2018). The U.S. Geological Survey analyzed radioisotope concentrations for lead-210, radium-226, cesium-127, and beryllium-7 from six marsh cores and three pond cores to develop an age model for each core. This data release includes calculated percent dry bulk density and raw radioisotope data for these cores. Spivak, A.C., Gosselin, K., Howard, E., Mariotti, G., Forbrich, I., Stanley, R., and Sylva, S.P., 2017, Shallow ponds are heterogeneous habitats within a temperate salt marsh ecosystem: Journal of Geophysical Research-Biogeosciences, 122(6), 1371-1384. Spivak, A. C., Gosselin, K. M., and Sylva, S.P., 2018, Shallow ponds are biogeochemically distinct habitats in salt marsh ecosystems: Limnology and Oceanography, 63(4), 1622-1642.