Latest Cretaceous and Paleocene biostratigraphy and paleogeography of northern Zealandia, IODP Site U1509, New Caledonia Trough, southwest Pacific

ABSTRACT

IODP Site U1509 (Expedition 371), New Caledonia Trough, provides a rare latest Cretaceous–Paleocene record from offshore northern Zealandia. We present new palynomorph and benthic foraminiferal assemblage data that show a transition from a latest Cretaceous vegetated sediment source region to a fully oceanic environment in the Paleocene. Latest Cretaceous (c. 68–66 Ma) non-calcareous claystone was deposited in upper bathyal paleodepths, with abundant plant microfossils that were likely transported in a northwest direction through the Aotea Basin region. A 2–3 Myr unconformity is identified at the Cretaceous/Paleogene boundary. Middle early–late Paleocene (c. 63.5–56 Ma) calcareous claystone shows evidence of deepening, deposited in middle bathyal or deeper paleodepths, and terrestrial input is minor. This latest Cretaceous to Paleocene deepening trend is consistent with inferred evolution of the Aotea and Northland basins further to the east, and other sparse northern Zealandia records, which show a common pattern of post-rift transgression consistent with long-term subsidence. Site U1509 allows for biogeographic extension and modification of the New Zealand Paleocene dinoflagellate zonation, description of a new dinoflagellate and pollen species, better inference of regional paleogeography, and may provide insights into the onset of western Pacific subduction initiation.

KEYWORDS:

• IODP Expedition 371
• IODP Site U1509
• northern Zealandia
• Late Cretaceous
• Paleocene
• biostratigraphy
• palynology
• benthic foraminifera
• paleogeography

Acknowledgements

We are grateful to Integrated Ocean Discovery Program (IODP) Expedition 371 Scientists and all personnel aboard the R/V JOIDES Resolution on IODP Expedition 371, and we thank IODP for providing samples and data used in this study. Peter Bijl is thanked for initial discussions and collaboration of this IODP Site, and Claudia Agnini provided helpful input into the manuscript. We thank Roger Tremain for palynological sample preparation, and Joe Prebble and Dominic Strogen for constructive internal manuscript reviews. Two external reviewers are thanked for their constructive and helpful comments that improved the paper.

Disclosure statement

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

Data availability statement

The supplementary data that support the finding of this study are openly available in GNS Science Dataset Catalogue at https://doi.org/10.21420/0E1D-9E89. Table 1: Qualitative occurrence data for Late Cretaceous spores/pollen from Site U1509. Table 2: Quantitative occurrence data for Late Cretaceous dinoflagellates from Site U1509. Table 3: Quantitative occurrence data for Paleocene dinoflagellates from Site U1509. Table 4: Occurrence data for Late Cretaceous and Paleocene benthic foraminiferal taxa with paleobathymetric significance from Site U1509. Additional analysis of core catcher samples (presence/absence of taxa) complements identifications in Sutherland et al. (2019). Semi-quantitative abundance estimates are given for samples from Cores 48R to 50R (late Middle Paleocene). R, rare (<2%); C, common (2–<5%); A, abundant (5–<15%); VA, very abundant (15–30%); D, dominant (>30%).

Additional information

Funding

EMC, CDC and JIR acknowledge support from the New Zealand Government’s Strategic Science Investment Fund through the Te Riu-a-Māui Zealandia Programme (C05X1702). LA would like to acknowledge Ministry of Economy and Competitiveness, Spain and Fondo Europeo de Desarrollo Regional, European Regional Development funds (PID2019-105537RB-I00).