Middle Eocene to the early Miocene northward migration of northern Zealandia determined from the sedimentary record of IODP Exp. 371 (Tasman Sea)
- 1Universität Bremen, Faculty of Geosciences, Marine Geophysics Research Group, Bremen, Germany (edoardo@uni-bremen.de)
- 2School of Geography, Environment and Earth Sciences, Victoria University of Wellington, New Zealand
- 3School of Natural Sciences, Trinity College Dublin, Ireland
- 4School of Earth and Space Sciences, Peking University, 100871 Beijing, China.
- 5Depratment of Earth Sciences, University of Turin, Italy
- 6Universidad de Zaragoza & Instituto Universitario de Ciencias Ambientales, Zaragoza, Spain
- 7Department of Geosciences, University of Padova, Italy
- 8MARUM, University of Bremen, Germany
- 9Network Stratigraphic Consulting Ltd., Potters Bar, UK
- 10Department of Geological Sciences and Environmental Studies, Binghamton University, SUNY, New York, USA
- 11GNS Sciences, Lower Hutt, New Zealand.
- 12Service de la Géologie de Nouvelle Calédonie, Direction de l'Industrie, des Mines et de l'Energie de Nouvelle Calédonie, Nouméa, New Caledonia
Northern Zealandia is a continent submerged for more than 90% under the water of the southwest Pacific Ocean and separated from Australia by the Tasman Sea ocean basin. Its absolute position since its drift form Australia in the Cretaceous is determined by means of global absolute plate motion models, as local paleomagnetic constraints are completely missing. We present new absolute paleolatitudes for northern Zealandia using paleomagnetic data from sediments drilled in International Ocean Discovery Program Sites U1507 and U1511 (Expedition 3711,2). After correcting for paleomagnetic inclination shallowing, typical of sediments, we derived five paleolatitude estimates that provide a trajectory of northern Zealandia past position from the middle Eocene to early Miocene, spanning geomagnetic polarity chrons C21n to C5Er (~48–18 Ma). Generally, our results support previous works on global absolute plate motion, including a rapid 6° northward migration of northern Zealandia between the early Oligocene–early Miocene. However, paleomagnetic-determined absolute paleolatitude is systematically lower, and this difference is significant in the Bartonian and Priabonian (C18n–C13r). This discrepancy may be explained by some degree of true polar wander, a solid Earth rotation with respect to the spin axis that can be resolved only using paleomagnetic data. These new paleomagnetic dataset anchors past latitudes of Zealandia to Earth’s spin axis, with implications not only for global geodynamics, but for addressing paleoceanographic problems, which generally require precise paleolatitude placement of proxy data3.
Figure 1. Present-day map of northern and southern Zealandia, enveloped respectively by the yellow and orange dashed line. The yellow stars indicate the location of International Ocean Discovery Program Sites U1507 (26.4886°S, 166.5286°E) and U1511 (37.5611°S, 160.3156°E). Solid and dashed white lines indicate active and inactive subduction zones, respectively, with arrows lying on the overriding plate. LHR = Lord Howe Rise, NCT = New Caledonia trough, NR = Norfolk Ridge, RB = Reinga basin.
(1) Sutherland, R. et al. Proc. Int. Ocean Discov. Progr. 371, 1–33 (2019); (2) Dallanave, E. & Chang, L. Newsletters Stratigr. 53, 365–387 (2020); (3) Dallanave, E. et al. J. Geophys. Res. Solid Earth 127, 1–19 (2022).
How to cite: Dallanave, E., Sutherland, R., Dickens, G., Chang, L., Tema, E., Alegret, L., Agnini, C., Westerhold, T., Newsam, C., Lam, A., Stratford, W., Collot, J., Etienne, S., and von Dobeneck, T.: Middle Eocene to the early Miocene northward migration of northern Zealandia determined from the sedimentary record of IODP Exp. 371 (Tasman Sea), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-6477, https://doi.org/10.5194/egusphere-egu23-6477, 2023.
