Postshield stage transitional volcanism on Mahukona Volcano, Hawaii
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.
KeywordsHawaii Volcanism Ar–Ar ages Eruptive stages He isotopes
We thank Gabi Laske, chief scientist of cruise TUIM01 on the R/V Melville in 2005 for providing the time to complete the dredge after the PLUME seismometer array was deployed. Alice Davis provided the microprobe analyses of the D6 glasses, which were completed at the US Geological Survey in Menlo Park, CA. Argon geochronology was funded by the USGS Volcano Hazards Program, and James Saburomaru assisted with the analyses. The TUIM01 cruise was supported by NSF grant OCE-00-02470. DAC was supported by a grant to the Monterey Bay Aquarium Research Institute from the David and Lucile Packard Foundation. Careful reviews by Tom Sisson, Bob Fleck, Tekeshi Hanyu, and associate editor Setsuya Nakada improved the manuscript.
- Calvert AT, Lanphere MA (2006) Argon geochronology of Kilauea’s early submarine history. In: Coombs ML, Eakins BW, Cervelli PF (eds) Growth and collapse of Hawaiian volcanoes. J Volcanol Geotherm Res 151:1–18Google Scholar
- Garcia MO, Kurz MD (1991) Reply to comment on “Mahukona: The missing Hawaiian Volcano”. Geology 19:1050Google Scholar
- Huang S, Abouchami W, Blichert-Toft J, Clague DA, Cousens BL, Frey FA (2007a) Geochemical structure of the Hawaiian Plume: inferences from Mahukona volcano. Goldschmidt Conference 2007, Cologne, Germany, Abstract A423: 104Google Scholar
- Huang S, Abouchami W, Blichert-Toft J, Clague DA, Cousens BL, Frey FA, Humayun M (2007b) Carbonate-rich sediment in the Hawaiian plume: evidence from Mahukona volcano. Eos Trans AGU 88(52), Fall Meeting Suppl, Abstract U21B-0415Google Scholar
- Kurz MD, Kenna T, Kammer D, Rhodes JM, Garcia MO (1995) Isotopic evolution of Mauna Loa volcano: a view from the submarine south west rift. In: Lockwood JP, Rhodes JM (eds) Mauna Loa revealed: structure, composition, history, and hazards. Am Geophys Union Geophys Mon 92:289–306Google Scholar
- Lipman PW, Sisson TW, Coombs ML, Calvert A, Kimura JI (2006) Piggyback tectonics: long-term growth of Kilauea on the south flank of Mauna Loa. In: Coombs ML, Eakins BW, Cervelli PF (eds) Growth and collapse of Hawaiian volcanoes. J Volcanol Geotherm Res 151:73–108Google Scholar
- MBARI Mapping Team (2001) Hawaii multibeam survey. Monterey Bay Aquarium Research Institute Digital Data Series No 2Google Scholar
- Stearns HT (1946) Geology of the Hawaiian Islands. Hawaii Division of Hydrography Bull 8:1–106Google Scholar
- Turner, G, Cadogan PH (1974) Possible effects of 39Ar recoil in 40Ar-39Ar dating. Proc 5th Lunar Sci Conf, pp 1601–1615Google Scholar
- Wolfe EW, Morris J (1996) Geologic map of the island of Hawaii. US Geol Surv Map I-2524-AGoogle Scholar