New U-Pb zircon ages and a revised integrated age model for the Late Miocene northern Taranaki coastal section, New Zealand

New LA-ICP-MS U-Pb zircon ages of tuffs, from the northern Taranaki coastal section constrain depositional ages of the Mount Messenger Formation to 9.69 ± 0.12 and 9.43 ± 0.17 Ma at the Mohakatino and Tongaporutu rivers, respectively, and the Urenui Formation near Waiau Stream to 8.45 ± 0.10 Ma. Our preferred new radiometric-biostratigraphic age model comprises lower and upper intervals characterised by relatively low and high un-decompacted sedimentation rates of 102 ± 96 m/Ma (MSWD = 6.0) and 1358 ± 144 m/Ma (MSWD = 1.32), respectively. The poor linear fit to the lower interval could indicate either variable sedimentation rates, or an unconformity (0.7 ± 0.2 Ma) in the upper Mohakatino Formation or at the base of the Mount Messenger Formation. The 1569 m-thick upper interval between Mohakatino River and Waiau Stream was deposited in 1.16 ± 0.01 Ma between 9.67 + 0.07/-0.05 and 8.52 + 0.06/-0.07 Ma. Predicted ages for intra-Tongaporutuan bioevents (e.g. base Tukemokihi Coiling Zone) do not overlap their assigned ages, highlighting the importance of propagating uncertainties into bioevent absolute ages and opportunities for future improvements to the age model, namely using high-precision geochronology to acquire ages for additional tuffs and improve precision of existing ages. (author)