Application of combined U-Th-disequilibrium/U-Pb and (U-Th)/He zircon dating to tephrochronology

In this review paper we summarize past developments and the current state of the ZDD method, explain the theoretical principles, and document the necessity of combining (U-Th)/He with U-Th-disequilibrium and/or U-Pb methods when dating young volcanic material. We then describe analytical procedures and highlight the advantages of the ZDD method. Finally, we present some examples that illustrate the efficacy of this method to derive reliable eruption ages for young tephras, and outline future directions in methodological development and application for this geochronological tool.