Biostratigraphically constrained chronologies for Quaternary sequences from the Hikurangi margin of north-eastern Zealandia

ABSTRACT

New biostratigraphically constrained chronologies have been developed to help elucidate the sedimentary and tectonic history of Quaternary sequences on the Hikurangi margin of north-eastern Zealandia. Three sites on the mid to lower slope of the accretionary prism (IODP Site 372-U1517, 375-U1519, 375-U1518) and two sites east of the deformation front (Hikurangi Trough Site 375-U1520 and Tūranganui Seamount Site 375-U1526) are dated using a detailed biostratigraphic framework based on planktic foraminiferal records from ODP Site 181-1123. The dating indicates sedimentation rates are very high and variable on the accretionary prism (0.2–9.6 m/kyr), especially during the Last Glacial Maximum (LGM) when downslope redeposition from the continental shelf and upper slope is common. Sedimentation rates at Hikurangi Trough Site 375-U1520 are also variable (0.01–3.0 m/kyr) and they increase markedly as the incoming site approached the deformation front, especially during the LGM, due to an abundance of downslope redeposition from the inner to mid shelf. The incoming Quaternary section at Tūranganui Seamount Site 375-U1526, is punctuated by hiatuses that shorten in duration as the site approached the deformation front, whilst sedimentation rates remain relatively low (0.04–0.4 m/kyr).

KEYWORDS:

• Quaternary
• planktic foraminifera
• biostratigraphy
• chronology
• IODP Expedition 372/375
• accretionary prism
• Hikurangi Trough
• Tūranaganui Seamount
• Hikurangi margin
• north-eastern Zealandia

Acknowledgements

This research used samples and data provided by the International Ocean Discovery Program (IODP). Henry Gard assisted with the preparation of samples, Jenny Black assisted with the preparation of figures, and Jenni Hopkins and Katharina Pank provided tephra data. Chris Clowes, Hugh Morgans, Helen Bostock, Adriane Lam, and Alan Orpin reviewed the original manuscript that has morphed into this paper and a companion paper by Crundwell and Woodhouse (2022) describing the Quaternary biostratigraphic framework for north-eastern Zealandia. We also thank Malcolm Arnot, Karsten Kroeger, Andrew Fraass, Alan Orpin, and an anonymous reviewer, for feedback on this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Supplemental files contain detailed data that underpins the identification of the biostratigraphic markers and subzones that the paper refers to. This data is openly available in Figshare at https://doi.org/10.6084/m9.figshare.19689253

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Additional information

Funding

This research was supported by the New Zealand Ministry of Business Innovation and Employment under SSIF funding contract CO5X1702.