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Eruptive origins of a lacustrine pyroclastic succession: insights from the middle Huka Falls Formation, Taupo Volcanic Zone, New Zealand

Citation

Cattell, HJ and Cole, JW and Oze, C and Allen, SR, Eruptive origins of a lacustrine pyroclastic succession: insights from the middle Huka Falls Formation, Taupo Volcanic Zone, New Zealand, New Zealand Journal of Geology and Geophysics, 57, (3) pp. 331-343. ISSN 0028-8306 (2014) [Refereed Article]

Copyright Statement

Copyright 2014 The Royal Society of New Zealand

DOI: doi:10.1080/00288306.2014.908930

Abstract

Current and ancestral lakes within the central Taupo Volcanic Zone (TVZ) provide depocentres for pyroclastic deposits, providing a reliable record of eruption history. These lakes can also be the source of explosive eruptions that directly feed pyroclast-rich density currents. The lithofacies characteristics of pyroclastic deposits allow discrimination between eruption-fed and resedimented facies. The most frequently recognised styles of subaqueous eruptions in the TVZ are shallow-water phreatomagmatic and phreatoplinian eruptions that form subaerial eruption columns. However, deeper source conditions (>150 m water depth) could generate subaqueous explosive eruptions that feed water-supported pyroclast-rich density currents, similar to neptunian eruptions. Such deep-water eruptions have not previously been recognised in the TVZ. Here we study a subsurface deposit, the middle Huka Falls Formation (MHFF), in the Wairakei–Tauhara Geothermal Fields (Wairakei–Tauhara), TVZ, which we interpret to be the product of a relatively deep-water pyroclastic eruption (150–250 m). The largely subsurface Huka Falls Formation records past sedimentary and volcaniclastic deposition in ancient Lake Huka. Deposits examined from eight drill cores reveal a lithic-rich lower unit, a middle volumetrically dominant pumice lapilli-tuff and an upper thinly bedded suspension-settled tuff unit. A coarse lithic lapilli-tuff within the lower unit is locally thick and coarse near well THM12, suggesting proximity to a source located beneath Lake Huka. This research provides an understanding of the origin of the MHFF deposit and offers insights for evaluating and interpreting the diversity of subaqueous volcanic lake deposits elsewhere.

Item Details

Item Type:Refereed Article
Keywords:subaqueous explosive eruption, lacustrine, Huka Falls Formation, Taupo Volcanic Zone, pumice, neptunian eruption, Lake Huka
Research Division:Earth Sciences
Research Group:Geology
Research Field:Volcanology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Allen, SR (Dr Sharon Allen)
ID Code:98513
Year Published:2014
Web of Science® Times Cited:4
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2015-02-18
Last Modified:2017-11-02
Downloads:0

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