Abstract
Prehistoric timescales, volcanic hazard assessment, and understanding of volcanogenic climate events rely on accurate dating of prehistoric eruptions. Most late Quaternary eruptions are dated by 14C measurements on material from close to the volcano that may be contaminated by geologic-sourced infinite-age carbon. Here we show that 14C ages for the Taupo (New Zealand) First Millennium eruption are geographically arrayed, with oldest ages closer to the vent. The current eruption wiggle match date of 232 ± 5 years CE is amongst the oldest. We present evidence that the older, vent-proximal 14C ages were biased by magmatic CO2 degassed from groundwater, and that the Taupo eruption occurred decades to two centuries after 232 CE. Our reinterpretation implies that ages for other proximally-dated, unobserved, eruptions may also be too old. Plateauing or declining tree ring cellulose δ13C and Δ14C values near a volcano indicate magmatic influence and may allow forecasting of super-eruptions.
Highlights
Prehistoric timescales, volcanic hazard assessment, and understanding of volcanogenic climate events rely on accurate dating of prehistoric eruptions
We interpret δ13C values of the wiggle match tree samples as indicating contamination by magmatic CO2 injected into the regional groundwater by accumulating basaltic magma beneath the rhyolitic magma chamber
Our demonstration that the 14C samples used to date the Taupo eruption were contaminated by on-edifice magmatic carbon implies that 14C ages on vent-proximal material for other eruptions may be affected by contamination
Summary
Prehistoric timescales, volcanic hazard assessment, and understanding of volcanogenic climate events rely on accurate dating of prehistoric eruptions. A recent example is the anchoring in 2011 of the SP04 (South Pole) ice core chronology[8] on the 1980-vintage, 186 CE date[9] for the Taupo (New Zealand) First Millennium eruption (hereafter, the Taupo eruption, or “Taupo”), rather than the 1995-vintage, 232 ± 15 years CE date[10]. We evaluate the pre-wiggle match 14C ages for the Taupo eruption and reveal a relationship between increasing distance from the vent and decreasing 14C age of samples associated with the eruption. We interpret δ13C values of the wiggle match tree samples as indicating contamination by magmatic CO2 injected into the regional groundwater by accumulating basaltic magma beneath the rhyolitic magma chamber.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
