serac

serac computes age-depth models for recent sediment cores using short-lived radionuclides (^210Pb_ex, ^137Cs, ^241Am) to establish chronologies of sedimentation over the past century.

Key Features:

• Implementation: Implemented as an R package for computational analysis of radionuclide data from sediment cores.
• Supported radionuclides: Uses measurements of ^210Pb_ex, ^137Cs, and ^241Am in surface sediments.
• Age-depth modeling: Computes age-depth models and timelines of sedimentation covering approximately the past century.
• Modeling methods: Supports Constant Flux-Constant Sedimentation (CFCS), Constant Initial Concentration (CIC), Constant Rate of Supply (CRS), and piecewise CRS models.
• Sedimentation hypothesis testing: Allows testing of changes in sedimentation rates, presence of instantaneous deposits, and varved sedimentation.
• Event markers: Uses ^137Cs and ^241Am as stratigraphic markers related to nuclear weapon tests and the Chernobyl accident.
• Outputs: Produces graphical age-depth correspondence, text files of age-depth data, and associated metadata for analysis.
• Reproducibility: Performs standardized, reproducible computations within the R environment.

Scientific Applications:

• Sediment core geochronology: Construction of age-depth models for recent sediment cores to date recent depositional history.
• Anthropogenic event dating: Identification and dating of nuclear-test and Chernobyl markers using ^137Cs and ^241Am.
• Sedimentation process analysis: Evaluation of changes in sedimentation rates, instantaneous depositional events, and varve preservation.
• Environmental and paleo studies: Chronological support for environmental and paleo studies in lakes, lagoons, and similar depositional settings.

Methodology:

Uses radionuclide measurements (^210Pb_ex, ^137Cs, ^241Am) from surface sediments; applies CFCS, CIC, CRS, and piecewise CRS modeling approaches; tests hypotheses on sedimentation rate changes, instantaneous deposits, and varved sedimentation; and computes age-depth models with graphical and text outputs plus metadata.