Leonard et al NZJGG 64 389 2021.pdf (12.65 MB)
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Ruapehu and Tongariro stratovolcanoes: a review of current understanding

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journal contribution
posted on 06.12.2021, 07:27 by GS Leonard, RP Cole, BW Christenson, CE Conway, SJ Cronin, John GambleJohn Gamble, T Hurst, BM Kennedy, CA Miller, JN Procter, LR Pure, DB Townsend, JDL White, Colin WilsonColin Wilson
Ruapehu (150 km3 cone, 150 km3 ring-plain) and Tongariro (90 km3 cone, 60 km3 ring-plain) are iconic stratovolcanoes, formed since ∼230 and ∼350 ka, respectively, in the southern Taupo Volcanic Zone and Taupo Rift. These volcanoes rest on Mesozoic metasedimentary basement with local intervening Miocene sediments. Both volcanoes have complex growth histories, closely linked to the presence or absence of glacial ice that controlled the distribution and preservation of lavas. Ruapehu cone-building vents are focused into a short NNE-separated pair, whereas Tongariro vents are more widely distributed along that trend, the differences reflecting local rifting rates and faulting intensities. Both volcanoes have erupted basaltic andesite to dacite (53–66 wt.% silica), but mostly plagioclase-two pyroxene andesites from storage zones at 5–10 km depth. Erupted compositions contain evidence for magma mixing and interaction with basement rocks. Each volcano has an independent magmatic system and a growth history related to long-term (>104 years) cycles of mantle-derived magma supply, unrelated to glacial/interglacial cycles. Historic eruptions at both volcanoes are compositionally diverse, reflecting small, dispersed magma sources. Both volcanoes often show signs of volcanic unrest and have erupted with a wide range of styles and associated hazards, most recently in 2007 (Ruapehu) and 2012 (Tongariro).

History

Preferred citation

Leonard, G. S., Cole, R. P., Christenson, B. W., Conway, C. E., Cronin, S. J., Gamble, J. A., Hurst, T., Kennedy, B. M., Miller, C. A., Procter, J. N., Pure, L. R., Townsend, D. B., White, J. D. L. & Wilson, C. J. N. (2021). Ruapehu and Tongariro stratovolcanoes: a review of current understanding. New Zealand Journal of Geology and Geophysics, 64(2-3), 389-420. https://doi.org/10.1080/00288306.2021.1909080

Journal title

New Zealand Journal of Geology and Geophysics

Volume

64

Issue

2-3

Publication date

01/01/2021

Pagination

389-420

Publisher

Informa UK Limited

Publication status

Published

Online publication date

02/05/2021

ISSN

0028-8306

eISSN

1175-8791

Language

en