Palaeogeographic evolution of Zealandia: mid-Cretaceous to present

ABSTRACT

We present a suite of 15 palaeogeographic maps illustrating the geological evolution of the entirety of Zealandia, from mid-Cretaceous to present, highlighting major tectonic phases, from initial Gondwana rifting through to development of the Neogene plate boundary. They illustrate palaeobathymetric and palaeofacies interpretations along with supporting geological datasets and a synthesis of regional tectonics. The maps are underpinned by a geologically-constrained and structurally-based rigid retro-deformation block model. This model, tied to the global plate circuit, is relatively simple for the main regions of Northern and Southern Zealandia, but breaks central Zealandia into numerous fault-bounded blocks, reflecting complex Neogene deformation associated with the modern plate boundary. Production of maps using GPlates and GIS allows for simple alteration or refinement of the block model and reconstruction of any geological dataset at any time. Reconstructions are within a palaeomagnetic reference frame, allowing assessment of palaeo-latitude, critical for palaeo-climatic and palaeo-biogeographic studies.

KEYWORDS:

• Palaeogeography
• tectonics
• Cretaceous
• Paleogene
• Neogene
• palaeobathymetry
• palinspastic reconstruction
• rifting
• subduction

Acknowledgements

This work has benefitted from discussions with many colleagues both at GNS Science and throughout the wider New Zealand geological community. Special thanks go to our colleagues Peter King and the late Mike Isaac for early inspiration and support for this work, to Nick Mortimer for highly fruitful tectonic discussions and providing volcanic ages from PETLAB, and to Chris Clowes for extracting useful data from the FRED database. Thanks for the use of the open source GPlates software, developed by the EarthByte Group at the University of Sydney. Many thanks to internal reviewers Nick Mortimer and Malcolm Arnot, to the journal reviewers Rupert Sutherland, Catherine Reid and Andy Nicol and to editor Richard Jongens, all of whom have helped to greatly improve this manuscript.

Disclosure statement

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

Data availability statement

The palaeogeographic reconstructions presented in this study have utilised open-file and published datasets, which are cited through the paper. All biostratigraphic data used are lodged in the New Zealand Fossil Record File (FRF; Clowes et al. 2021), accessible at https://fred.org.nz/. Data regarding the ages of onshore and offshore volcanic rock samples were extracted from PETLAB (Strong et al. 2016), accessible at http://pet.gns.cri.nz/. Onshore geological map data were derived from the QMAP Seamless 1:250k digital dataset, held by GNS and accessible via https://www.gns.cri.nz/Home/Products/Maps. Digital (GIS) palaeogeographic maps, illustrated seismic transects, and digital (GIS) seismic depth-grids relating to the ‘Atlas of Petroleum Prospectivity’ (APP) programme, are accessible for download from https://data.gns.cri.nz/pbe/, via digital Petroleum Exploration Data Packs distributed by New Zealand Petroleum & Minerals (MBIE; https://www.nzpam.govt.nz/), or by contacting the authors. A supplemental file providing more detailed descriptions of the palaeogeographic reconstructions presented in this paper and all referenced material used in their construction, is available in figshare via https://doi.org/10.6084/m9.figshare.20500113.

Additional information

Funding

This project was supported by the New Zealand Ministry of Business, Innovation and Employment (MBIE) through the Understanding Zealandia/Te Riu-a-Māui (UZTRM) programme (Strategic Science Investment Fund, contract C05X1702), and previously by the SSIF funded Sedimentary Basins and Petroleum research programmes. It incorporates many of the results of the Atlas of Petroleum Prospectivity (APP) programme, funded through the MBIE Energy and Minerals targeted research fund. BRH was funded by a Sarah Beanland Memorial Scholarship, awarded by GNS Science.