Resolving challenges in the development of a protocol for δ¹⁸O determinations on tree-ring cellulose

Area of Science:

• Paleoclimatology
• Isotope Geochemistry
• Dendrochronology

Background:

• Tree rings offer annual records of past environmental and climatic conditions.
• Oxygen isotope (δ18O) analysis in tree-ring cellulose provides insights into hydroclimate and tree-environment interactions.
• Accurate δ18O chronologies are valuable for archaeological dating and climate reconstructions.

Purpose of the Study:

• To establish a robust methodology for producing and measuring δ18O in tree-ring alpha-cellulose.
• To assess the precision and reliability of the developed measurement technique.
• To address challenges in calibrating δ18O determinations using various reference materials.

Main Methods:

• Development of a working methodology for δ18O analysis in tree-ring α-cellulose.
• Utilizing continuous flow isotope ratio mass spectrometry (IRMS).
• Calibration using water reference materials and quality control standards, including IAEA-C3 holocellulose.

Main Results:

• Achieved an average precision of approximately 0.2‰ for δ18O determinations in tree-ring cellulose.
• Identified calibration difficulties when using non-cellulose organic reference materials due to pyrolysis behavior.
• Successfully calibrated cellulose standards against the VSMOW-SLAP scale using appropriate reference materials.

Conclusions:

• The established methodology offers high precision for δ18O analysis in tree-ring cellulose.
• Further research is needed to resolve calibration issues with non-cellulose organic standards.
• The validated method enhances the reliability of tree-ring isotope data for climate and archaeological studies.