Using a cesium-137 (137Cs) sedimentary fallout record in the South Atlantic Ocean as a supporting tool for defining the Anthropocene

Publication date: Available online 29 June 2016
Source:Anthropocene
Author(s): Paulo Alves de Lima Ferreira, Rubens Cesar Lopes Figueira, Eduardo Siegle, Nils Edvin Asp Neto, César de Castro Martins, Carlos Augusto França Schettini, Pablo Muniz Maciel, Felipe García-Rodriguez, Michel Michaelovitch de Mahiques
Human civilization is causing many changes to the global environment, such as the widespread presence of coastal cities and air, soil and water pollution. A new stratigraphic term for the current age, the Anthropocene, has been proposed and is differentiated from the Holocene by anthropogenic alterations. This study evaluated the occurrence and distribution of an artificial radionuclide, cesium-137 (¹³⁷Cs), in coastal sediments of the South Atlantic Ocean through the analysis of a large number of sediment cores covering a wide latitudinal band (0°−35°S). The age of this radionuclide's horizon of maximum activity is validated with unsupported lead-210 (²¹⁰Pb) dating and its use is directly related to the peak of the past atmospheric fallout of nuclear tests in 1963, showing its radioactive record to be a short- to mid-term chronostratigraphic marker of this year and its use in helping to define the beginning of the Anthropocene. The presence of fallout ¹³⁷Cs follows a latitudinal pattern with a mid-latitude maximum at approximately 35°S and lower values toward the equator. This result agrees with observations reported in the international literature regarding the deposition of fallout radioactivity.



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