Delta-X: Soil Accretion Rates from Cs-137 Activity and NUMAR Validation, MRD, LA

This dataset holds measurements of Cesium-137 (137Cs) activity sampled from sites in the Atchafalaya and Terrebonne Basins on the southern coast of Louisiana, USA. Sediment cores were taken to validate modeled estimates of soil accretion rates. The NUMAR model was designed to predict soil properties and corresponding accretion rates in marsh environments. This study explored whether the probabilistic outcomes generated by the model align with accretion rates determined through field-based measurements using 137Cs activity. The model's probabilistic simulations were conducted for active and inactive basins, encompassing fresh, brackish, and saline sites. Aliquots of approximately 5-9 g of finely ground dry sediment were placed into vials of known geometry for direct gamma counting of 137Cs using high-purity Germanium (Ge) well detectors. The 137Cs dating technique is based on detecting the specific core section in which the radioactive isotope 137Cs peak activity occurs across a vertical soil profile. This peak corresponds to the peak fallout in 1963 deposited during the atmospheric nuclear testing and provides a timeline reference for estimating soil accumulation rates, sediment deposition, and marsh accretion. Therefore, to validate the NUMAR accretion results, 137Cs activity was measured at different core sections across a vertical soil profile to determine the peak corresponding to the peak fallout in 1963 due to atmospheric nuclear testing and estimate soil accretion rates. The data are provided in comma separated values (CSV) format.

Data and Resources

Additional Info

Field Value
Maintainer Earthdata Forum
Last Updated October 27, 2026, 02:05 (UTC)
Created April 1, 2025, 15:23 (UTC)
Identifier 10.3334/ORNLDAAC/2380
Modified 2026-10-19T22:16:06Z
Theme {"Earth Science"}
accessLevel public
bureauCode {026:00}
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harvest_object_id 3bdceb3e-6aaa-4c24-a108-61b600927961
harvest_source_id b99e41c6-fe79-4c19-bbc3-9b6c8111bfac
harvest_source_title Science Discovery Engine
license https://www.usa.gov/government-works
programCode {026:000}
publisher ORNL_DAAC
resource-type Dataset
source_datajson_identifier true
source_hash ff63df85a7af8d518baedf4c13640d3387428e83a027086ccde5d07b2138837c
source_schema_version 1.1
spatial ["CARTESIAN", [{"WestBoundingCoordinate": -91.4417, "NorthBoundingCoordinate": 29.5643, "EastBoundingCoordinate": -90.8225, "SouthBoundingCoordinate": 29.1714}]]
temporal 2021-09-22/2023-04-23