Late Triassic‐Early Jurassic palynofloral assemblages from Murihiku strata of New Zealand, and comparisons with China

Abstract

Marine deposition in the Murihiku Terrane gave apparently continuous sequences across the Triassic‐Jurassic boundary which were sampled in sections in south‐west Kawhia and the Awakino Gorge, south west Auckland, and in the Hokonui Hills, Southland Palynological analysis shows diverse microfloras totalling 71 genera and 119 species These floras come from the Ngutunui, Arataura, Rewarewa, and Arawhero Formations of the Newcastle Group, Kawhia, the Ngutunui Formation and undifferentiated Newcastle strata, Awakino Gorge, and the Trechmann Siltstone and associated unnamed units in Southland Four palynofloral assemblages can be distinguished among samples from these sequences In ascending order they are Assemblage I, Otamitan (Early‐Middle Norian), Polycingulatisporites crenulatus‐Annulispora microannulata‐Aratrisporites flexibilis Assemblage, Assemblage II, Otapirian (Rhaetian), Foveosporites moretonensis‐Densoisporites psilatus‐Steevesipollenites claviger Assemblage, Assemblage III, late Otapirian‐early Aratauran (Hettangian), Toripustulatisporites hokonuiensis‐Kyrtomisporis minor‐Polycingulatisporites radiatus Assemblage, Assemblage IV, Aratauran (Hettangian‐Sinemurian) Classopollis chateaunovi‐Lycopodiumsporites austroclavatidites Assemblage The Triassic‐Jurassic boundary is judged to he between Assemblages II and III, and thus within the upper part of the local Otapirian Stage, which occurs at about the top of the Ngutunui Formation in the Kawhia section