title: Constraints on the use of 137Cs as a time-marker to support CRS and SIT chronologies.
abstract: CRS and SIT are two (210)Pb-based models widely used in the radiometric dating of recent sediments. (210)Pb chronologies should be validated using at least one independent tracer, such as (137)Cs. This paper demonstrates that simple methods based on the identification of (137)Cs fallout peaks cannot provide a definitive support for CRS and SIT chronologies. Two main arguments will support this assertion: Firstly, the (137)Cs time-marks cannot support a CRS or SIT chronology if the derived sedimentation rates cannot explain the whole (137)Cs activity profile without postulating mixing. Secondly, the support by the (137)Cs time-marks for a given CRS or SIT chronology cannot be considered as definitive if other dating models can equally explain the whole set of data, thereby producing a different chronology. Several case studies selected from the literature are used to support the present discussion.
authors.affiliation: Dpto. Física Aplicada I. University of Seville, E.U.I.T.A., Carretera de Utrera km 1, D.P. 41013., Seville, Spain. jmabril@us.es
authors.forename: J M
authors.initials: JM
authors.lastname: Abril
mesh_terms: D002588:Cesium Radioisotopes / Q000737:chemistry*; D002910:Chronology as Topic; D019015:Geologic Sediments / Q000737:chemistry*; D007856:Lead Radioisotopes; D008962:Models, Theoretical; D011851:Radioactivity
chemical_list: D002588:Cesium Radioisotopes; D007856:Lead Radioisotopes