C05_P01

Radiocarbon analysis of annually published journals

Gautschi P¹, Brehm N¹, Wertnik M¹, Synal H¹, Wacker L¹

¹ETH Zurich, Zurich, Switzerland

The paper of books or journals is typically produced from cellulose extracted from trees. This makes them potentially suitable for radiocarbon dating. However, precise calendar age determination of the measured radiocarbon ages is difficult. Paper production has a lot of unknown factors such as different tree ages, i.e. number of tree rings, which go into the production of cellulose. Additionally, storage time between harvest of a tree and final publication is usually unknown and may vary. Therefore, the atmospheric integration time of a paper product, is an unknown distribution.

A series of 52 annually published journals over the ¹⁴C bomb pulse (1947 - 2021 AD) have been prepared for radiocarbon analysis to study the age assembly and the storage time of trees used for the paper. The measured ¹⁴C concentrations were compared to modelled ¹⁴C concentrations in paper, which are based on a simple tree-ring model and assuming the cellulose was formed from atmospheric CO₂ at the year of formation. Best agreements were obtained assuming a mean age of trees of 40 to 80 years and a relatively short storage time of two years between the harvest of trees and the final publication. Although the measured journals follow the model qualitatively, some significant deviations were observed between individual years of publication.