Holocene evolution of the southern Tauranga Harbour

David MacPherson, Bethany R.S. Fox, Willem P. de Lange

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Tauranga Harbour is a major economic centre and home to New Zealand’s largest port. Despite the importance of the harbour basin, and especially of the shipping channel, the subsurface stratigraphy of this area has not been studied in detail. We use sediment cores retrieved in support of a recent dredging campaign to characterise the subsurface stratigraphy and interpret the sediments in terms of paleoenvironment. Four main facies (volcanic sand, lithic silt, coarse sand and pumiceous sand) were identified using textural, mineralogical and geochemical characteristics. They represent distinct depositional environments at different stages of the Holocene marine transgression (HMT). The oldest facies, deposited prior to the HMT (volcanic sand and lithic silt facies), represent the channel and overbank deposits of an aggrading river system with rapidly migrating channels. During the deposition of this facies, a change in sediment source is evident from geochemical data. This preceded a transition to a predominantly offshore sediment source (coarse sand facies), likely supplied by longshore drift from the Kaituna River, which was associated with the development of Mt Maunganui tombolo and Matakana barrier island. During the Holocene stillstand, the barrier island and tombolo restricted sediment input from offshore, resulting in the deposition of a predominantly locally derived unit (pumiceous sand facies), which still dominates sedimentation in the harbour today.

Original languageEnglish
Pages (from-to)392-409
Number of pages18
JournalNew Zealand Journal of Geology and Geophysics
Volume60
Issue number4
Early online date21 Aug 2017
DOIs
Publication statusPublished - 2 Oct 2017
Externally publishedYes

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harbors
sands
harbor
Holocene
sediments
sand
barrier island
stratigraphy
rivers
transgression
sediment
volcanology
silt
dredging
New Zealand
paleoenvironment
shipping
depositional environment
river system
sediment core

Cite this

MacPherson, David ; Fox, Bethany R.S. ; de Lange, Willem P. / Holocene evolution of the southern Tauranga Harbour. In: New Zealand Journal of Geology and Geophysics. 2017 ; Vol. 60, No. 4. pp. 392-409.
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Holocene evolution of the southern Tauranga Harbour. / MacPherson, David; Fox, Bethany R.S.; de Lange, Willem P.

In: New Zealand Journal of Geology and Geophysics, Vol. 60, No. 4, 02.10.2017, p. 392-409.

Research output: Contribution to journalArticle

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