The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0–55 cal kBP)

• DOI: 10.1017/rdc.2020.41
• Publication Date: 2020-08-12T07:02:24Z
• Authors: Paula J Reimer; William E N Austin; Edouard Bard; Alex Bayliss; Paul G Blackwell; Christopher Bronk...; Martin Butzin; Hai Cheng; R Lawrence Edwards; Michael Friedrich; Pieter M Grootes; Thomas P Guilderson; Irka Hajdas; Timothy J Heaton; Alan G Hogg; Konrad A Hughen; Bernd Kromer; Sturt W Manning; Raimund Muscheler; Jonathan G Palmer; Charlotte Pearson; Johannes van der ...; Ron W Reimer; David A Richards; E Marian Scott; John R Southon; Christian S M Turney; Lukas Wacker; Florian Adolphi; Ulf Büntgen; Manuela Capano; Simon M Fahrni; Alexandra Fogtman...; Ronny Friedrich; Peter Köhler; Sabrina Kudsk; Fusa Miyake; Jesper Olsen; Frederick Reinig; Minoru Sakamoto; Adam Sookdeo; Sahra Talamo
• Keywords: 550; anzsrc-for: 0406 Physical Geography and Environmental Geoscience; 3705 Geology; calibration curve radiocarbon IntCal20; 01 natural sciences; 333; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; calibration curve; anzsrc-for: 4301 Archaeology; 14. Life underwater; R2C; 0105 earth and related environmental sciences; GE; IntCal20; anzsrc-for: 3709 Physical Geography and Environmental Geoscience; 37 Earth Sciences; anzsrc-for: 37 Earth Sciences; anzsrc-for: 3705 Geology; anzsrc-for: 0402 Geochemistry; 3rd-DAS; 3709 Physical Geography and Environmental Geoscience; 14 Life Below Water; Radiocarbon; Calibration curve; Radiocarbon; IntCal20; 13. Climate action; anzsrc-for: 2101 Archaeology; radiocarbon; anzsrc-for: 3703 Geochemistry; Calibration curve; BDC; GE Environmental Sciences

ABSTRACTRadiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.