New Zealand Journal of Geology and Geophysics abstracts
Stratigraphy and chronology of a 15 ka sequence of multi-sourced silicic
tephras in a montane peat bog, eastern North Island, New Zealand
DAVID J. LOWE
Department of Earth Sciences
University of Waikato
Private Bag 3105
Hamilton, New Zealand
email: d.lowe@waikato.ac.nz
REWI M. NEWNHAM
Department of Geographical Sciences
University of Plymouth
Plymouth, Devon PL4 8AA
England, United Kingdom
email: r.newnham@plymouth.ac.uk
CHRIS M. WARD
Department of Conservation
P.O. Box 668
Gisborne, New Zealand
email: cward@doc.govt.nz
Abstract We document the stratigraphy, composition, and
chronology of a succession of 16 distal, silicic tephra layers interbedded with
lateglacial and Holocene peats and muds up to c. 15 000 radiocarbon
years (c. 18 000 calendar years) old at a montane site (Kaipo Bog) in eastern
North Island, New Zealand. Aged from 665 +/- 15 to 14 700 +/- 95
14C yr BP, the tephras are derived from six volcanic centres in
North Island, three of which are rhyolitic (Okataina, Taupo, Maroa), one
peralkaline (Tuhua), and two andesitic (Tongariro, Egmont). Correlations are
based on multiple criteria: field properties and stratigraphic
interrelationships, ferromagnesian silicate mineral assemblages, glass-shard
major element composition (from electron microprobe analysis), and radiocarbon
dating. We extend the known distribution of tephras in eastern North Island and
provide compositional data that add to their potential usefulness as
isochronous markers. The chronostratigraphic framework established for the
Kaipo sequence, based on both site-specific and independently derived
tephra-based radiocarbon ages, provides the basis for fine-resolution
paleoenvironmental studies at a climatically sensitive terrestrial site from
the mid latitudes of the Southern Hemisphere. Tephras identified as especially
useful paleoenvironmental markers include Rerewhakaaitu and Waiohau
(lateglacial), Konini (lateglacial-early Holocene), Tuhua (middle Holocene),
and Taupo and Kaharoa (late Holocene).
Keywords tephra; tephrostratigraphy; tephrochronology; glass
analysis; peat; radiocarbon dates; volcanism; late Quaternary; lateglacial;
Holocene; Kaipo Bog; Te Urewera National Park; New Zealand
New Zealand Journal of Geology & Geophysics, 1999, Vol. 42:
565-579
0028-8306/99/4204-0565 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (2268K); (scanned from paper original: notes about this process)
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