Bulletin of Volcanology

, Volume 71, Issue 5, pp 533–539

Postshield stage transitional volcanism on Mahukona Volcano, Hawaii

Research Article


Age spectra from 40Ar/39Ar incremental heating experiments yield ages of 298 ± 25 ka and 310 ± 31 ka for transitional composition lavas from two cones on submarine Mahukona Volcano, Hawaii. These ages are younger than the inferred end of the tholeiitic shield stage and indicate that the volcano had entered the postshield alkalic stage before going extinct. Previously reported elevated helium isotopic ratios of lavas from one of these cones were incorrectly interpreted to indicate eruption during a preshield alkalic stage. Consequently, high helium isotopic ratios are a poor indicator of eruptive stage, as they occur in preshield, shield, and postshield stage lavas. Loihi Seamount and Kilauea are the only known Hawaiian volcanoes where the volume of preshield alkalic stage lavas can be estimated.


Hawaii Volcanism Ar–Ar ages Eruptive stages He isotopes 

Supplementary material

445_2008_240_MOESM1_ESM.pdf (474 kb)
ESM 1(PDF 485 KB)

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Monterey Bay Aquarium Research InstituteMoss LandingUSA
  2. 2.US Geological SurveyMenlo ParkUSA

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