δ13C values in archaeological 14C-AMS dated charcoals: assessing mid-Holocene climate fluctuations and human response from a high-resolution isotope record (Arslantepe, Turkey)
Rationale: Past climate has always influenced human adaptation to the environment.
In order to reconstruct palaeoclimate fluctuations and their role in the evolution of Near
Eastern societies during the mid‐Holocene, high‐resolution Δ13C records from fossil
wood remains at the archaeoloical site of Arslantepe (eastern Turkey) have been
developed.
Methods: After chemical treatment, δ13C values were measured by sample
combustion flow using a FLASH EA‐CHNS instrument interfaced with a Delta V isotope
ratio mass spectrometer via a CONFLO III. Two replicates per sample were analysed.
The measurement precision was evaluated by propagating variations of the δ13C
values of samples and V‐PDB standards, whereas the accuracy was checked by a quality
control sample. To account for changes in atmospheric CO2, Δ13C values were
calculated. In addition, 14C/12C ratios were measured by means of an AMS system
(3 MV tandem accelerator).
Results: Mean Δ13C curves of deciduous Quercus and Juniperus from archaeological
levels between 4700 and 2000 BC (Arslantepe periods VIII‐VI D) were produced,
where the isotope values were ordered by the available Radiocarbon ages.
Interspecific variations of evergreen vs deciduous plants were postulated for the
juniper Δ13C values being higher than 3‰. The seasonal rainfall amount was recorded
by the juniper remains, while the water table levels were obtained from the oak samples.