Soil Accretion Rates from Cesium-137 Activity in Louisiana Marshes

Field measurements of Cesium-137 (137Cs) activity from sediment cores in the Atchafalaya and Terrebonne Basins of Louisiana, USA, were collected to validate the NUMAR model's probabilistic predictions of soil accretion rates. The data, provided in CSV format, uses the 1963 peak fallout signature from atmospheric nuclear testing as a chronological marker to estimate sediment deposition and marsh accretion. The dataset is associated with the Delta-X project and was last updated in March 2026.

Use Cases

• Validating the NUMAR model's probabilistic soil accretion rate predictions against field-measured 137Cs peak depths.
• Estimating historical soil accumulation and sediment deposition rates in coastal marshes using the 1963 137Cs fallout peak.
• Comparing accretion rates across different marsh types (fresh, brackish, saline) and basin activity states (active, inactive).
• Analyzing vertical soil profiles for geochemical properties related to isotopic age and sedimentation processes.

Strengths

• Data is derived from direct gamma counting using high-purity Germanium (Ge) well detectors on precisely prepared 5-9g sediment aliquots.
• The dataset's cross-platform presence on NASA EarthData and Data.gov signals its importance and reusability for the scientific community.
• The 137Cs dating technique provides a specific, globally recognized chronological marker (1963 peak) for estimating accretion rates.

Limitations

• Specific column names, row counts, and dataset size are not provided by any source, limiting immediate analytical utility.
• Sources conflict on the last updated date, with one listing March 2026 and another April 2023, creating uncertainty about data currency.

Provenance

Source

ORNL_CLOUD

Collection Method

Sediment cores were taken, processed into finely ground dry sediment, and analyzed via direct gamma counting for 137Cs activity.

Time Range

The temporal coverage is defined by the 1963 fallout peak used as a marker, but the specific sampling date range is unknown.

Freshness

2026-03-13 03:16:43.059895

Geography

Atchafalaya and Terrebonne Basins on the southern coast of Louisiana, USA.