Fluctuating radiocarbon offsets observed in the southern Levant and implications for archaeological chronology debates

Proc Natl Acad Sci U S A. 2018 Jun 12;115(24):6141-6146. doi: 10.1073/pnas.1719420115. Epub 2018 May 29.

Abstract

Considerable work has gone into developing high-precision radiocarbon (14C) chronologies for the southern Levant region during the Late Bronze to Iron Age/early Biblical periods (∼1200-600 BC), but there has been little consideration whether the current standard Northern Hemisphere 14C calibration curve (IntCal13) is appropriate for this region. We measured 14C ages of calendar-dated tree rings from AD 1610 to 1940 from southern Jordan to investigate contemporary 14C levels and to compare these with IntCal13. Our data reveal an average offset of ∼19 14C years, but, more interestingly, this offset seems to vary in importance through time. While relatively small, such an offset has substantial relevance to high-resolution 14C chronologies for the southern Levant, both archaeological and paleoenvironmental. For example, reconsidering two published studies, we find differences, on average, of 60% between the 95.4% probability ranges determined from IntCal13 versus those approximately allowing for the observed offset pattern. Such differences affect, and even potentially undermine, several current archaeological and historical positions and controversies.

Keywords: archaeology; calibration; radiocarbon; radiocarbon offsets; southern Levant.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't