Radiocarbon (14C) concentrations in the oceans are different from those in the atmosphere. Understanding these ocean-atmospheric 14C differences is important both to estimate the calendar ages of samples which obtained their 14C in the marine environment, and to investigate the carbon cycle. The Marine20 radiocarbon age calibration curve is created to address these dual aims by providing a global-scale surface ocean record of radiocarbon from 55,000-0 cal yr BP that accounts for the smoothed response of the ocean to variations in atmospheric 14C production rates and factors out the effect of known changes in global-scale palaeoclimatic variables. The curve also serves as a baseline to study regional oceanic 14C variation. Marine20 offers substantial improvements over the previous Marine13 curve. In response to community questions, we provide a short intuitive guide, intended for the lay-reader, on the construction and use of the Marine20 calibration curve. We describe the choices behind the making of Marine20, as well as the similarities and differences compared with the earlier Marine calibration curves. We also describe how to use the Marine20 curve for calibration and how to estimate ΔR - the localized variation in the oceanic 14C levels due to regional factors which are not incorporated in the global-scale Marine20 curve. To aid understanding, illustrative worked examples are provided.
Bibliographical noteFunding Information:
P. Köhler and M. Butzin are supported by the German Federal Ministry of Education and Research (BMBF), as Research for Sustainability initiative (FONA); www.fona.de through the PalMod project (grant numbers: 01LP1505B, 01LP1919A), which also covered the Open Access fees. E. Bard is funded by EQUIPEX ASTER-CEREGE and ANR MARCARA.
© The Author(s), 2022. Published by Cambridge University Press for the Arizona Board of Regents on behalf of the University of Arizona.
- marine calibration
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)