New Zealand Journal of Geology and Geophysics abstracts

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Geochemical characteristics of the widespread Tahuna Tephra

Victoria Smith

Phil Shane

Department of Geology
University of Auckland
Private Bag 92019
Auckland, New Zealand

Abstract   The c. 40 000 yr Tahuna Tephra found throughout the central North Island, New Zealand, and offshore in the Bay of Plenty, is considered to have erupted from the Okataina Volcanic Centre. Its glass and mineral chemistry, eruption temperature, and fO₂ are dissimilar to Okataina-sourced Mangaone Subgroup tephra with which it is interbedded in the Bay of Plenty. Instead, Tahuna Tephra displays a compositional affinity to pre-22 000 yr tephra from Taupo Volcanic Centre. A Taupo source is also more consistent with the tephraÕs thickness and coarseness at Lake Poukawa in southern North Island.

Keywords   Tahuna Tephra; Okataina Volcanic Centre; Taupo Volcanic Centre; tephra; tephrochronology; Mangaone Subgroup

Received 11 December 2000; accepted 5 September 2001
New Zealand Journal of Geology & Geophysics, 2002, Vol. 45 : 103–107
0028–8306/02/0103 $7.00/0 © The Royal Society of New Zealand 2002

PDF file of entire paper: Print-quality (123K)

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