Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates
MetadataShow full item record
KeywordBioturbation; Radioisotopes; Chronostratigraphy; Sediment mixing; Geochronometry; Fallout; Lead 210; Caesium; Sediment mixing; Modelling
Sedimentary records of naturally occurring and fallout-derived radionuclides are widely used as tools for estimating both the ages of recent sediments and rates of sedimentation and bioturbation. Developing these records to the point of data interpretation requires careful sample collection, processing, analysis and data modeling. In this work, we document a number of potential pitfalls that can impact sediment core records and their interpretation. This paper is not intended as an exhaustive treatment of these potential problems. Rather, the emphasis is on potential problems that are not well documented in the literature, as follows: 1) The mere sampling of sediment cores at a resolution that is too coarse can result in an apparent diffusive mixing of the sedimentary record at rates comparable to diffusive bioturbation rates observed in many locations; 2) 210Pb profiles in slowly accumulating sediments can easily be misinterpreted to be driven by sedimentation, when in fact bioturbation is the dominant control. Multiple isotopes of different half lives and/or origin may help to distinguish between these two possible interpretations; 3) Apparent mixing can occur due simply to numerical artifacts inherent in the finite difference approximations of the advection diffusion equation used to model sedimentation and bioturbation. Model users need to be aware of this potential problem. Solutions to each of these potential pitfalls are offered to ensure the best possible sediment age estimates and/or sedimentation and bioturbation rates can be obtained.
Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Estuarine, Coastal and Shelf Science 71 (2007): 537-544, doi:10.1016/j.ecss.2006.09.006.
Suggested CitationPreprint: Crusius, John, Kenna, Timothy C., "Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates", 2006-09-11, https://doi.org/10.1016/j.ecss.2006.09.006, https://hdl.handle.net/1912/1603
Showing items related by title, author, creator and subject.
The sediments of the western Gulf of Mexico. I. The continental terrace of the western Gulf of Mexico : its surface sediments, origin, and development. II. Chemical studies of sediments of the western Gulf of Mexico Stetson, Henry C.; Trask, Parker D. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1953-05)In 1947 the Woods Hole Oceanographic Institution organized an expedition to investigate the bottom sediments and oceanography of the northwest Gulf of Mexico. The Geological Society of America contributed to the support ...
Quantity, composition, and source of sediment collected in sediment traps along the fringing coral reef off Molokai, Hawaii Bothner, Michael H.; Reynolds, Richard L.; Casso, Michael A.; Storlazzi, Curt D.; Field, Michael E. (Elsevier B.V., 2006-03-20)Sediment traps were used to evaluate the frequency, cause, and relative intensity of sediment mobility/resuspension along the fringing coral reef off southern Molokai (February 2000–May 2002). Two storms with high rainfall, ...
Cohesive and mixed sediment in the Regional Ocean Modeling System (ROMS v3.6) implemented in the Coupled Ocean–Atmosphere–Wave–Sediment Transport Modeling System (COAWST r1234) Sherwood, Christopher R.; Aretxabaleta, Alfredo L.; Harris, Courtney K.; Rinehimer, J. Paul; Verney, Romaric; Ferré, Bénédicte (Copernicus Publications on behalf of the European Geosciences Union, 2018-05-14)We describe and demonstrate algorithms for treating cohesive and mixed sediment that have been added to the Regional Ocean Modeling System (ROMS version 3.6), as implemented in the Coupled Ocean–Atmosphere–Wave–Sediment ...