thumbnail

Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates

Estuarine, Coastal and Shelf Science

By:
and
DOI: 10.1016/j.ecss.2006.09.006

Links

Abstract

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.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Ensuring confidence in radionuclide-based sediment chronologies and bioturbation rates
Series title:
Estuarine, Coastal and Shelf Science
DOI:
10.1016/j.ecss.2006.09.006
Volume
71
Issue:
3-4
Year Published:
2007
Language:
English
Publisher:
Elsevier
Contributing office(s):
Coastal and Marine Geology Program
Description:
8 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Estuarine, Coastal and Shelf Science
First page:
537
Last page:
544
Number of Pages:
8