Marine invertebrate fossils from the Permian–Triassic boundary beds of two core sections in the northern Perth Basin, Western Australia

Abstract

Marine macroinvertebrate fossils from two petroleum exploration cores, Apium-1 and Redback-2, are described, and found to contain two separate assemblages. The assemblage from the Apium-1 core was recovered from an ca 5-m-thick interval (2756.35–2751.28 m) in the basal Hovea Member (‘inertinitic interval’) of the Kockatea Shale and includes the following forms: ?Spinomarginifera sp., Cimmeriella sp., ?Etherilosia sp., Elivina sp., Cleiothyridina sp., and Paeckelmanelloidea gen. et. sp. indet. (all brachiopods). The age of this assemblage is interpreted as Changhsingian, as constrained by its association with the palynofloral Dulhuntyispora parvithola Zone. The assemblage from the Redback-2 core was recovered from the ‘sapropelic interval’ of the Hovea Member of the Kockatea Shale between 3806 m and 3786 m and comprises the following forms: Lingulidae gen. et sp. indet. (brachiopod), Claraia perthensis Dickins & McTavish, Crittendenia cf. australasiatica (Krumbeck), ?Paralledon sp. (bivalves), ?Otoceras sp. (ammonoid), Microconchus utahensis Zatoń, Taylor & Vinn (microconchid) and Magniestheria mangaliensis (Jones) (spinicaudatan). Among these, the first local appearances of the lingulid species, ?Otoceras sp. and M. mangaliensis are associated with the palynofloral Protohaploxypinus microcorpus Zone and are interpreted as latest Changhsingian in age. Other occurrences of the Redback-2 fossil assemblage overlap with the palynofloral Kraeuselisporites saeptatus Zone and are considered to be of earliest Triassic (Griesbachian) age. G.R. Shi [guang@uow.edu.au] and Sangmin Lee [sangminlee76@gmail.com], School of Earth, Atmospheric and Life Sciences, University of Wollongong, Northfields Ave, Wollongong, NSW 2522, Australia; Ian Metcalfe [imetcal2@une.edu.au], Earth Sciences, Earth Studies Building C02, School of Environmental and Rural Science, University of New England, Armidale, NSW 2351, Australia; Daoliang Chu [chudl@cug.edu.cn], State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan 430074, PR China; Huiting Wu [ht_wu415@163.com], College of Geoscience and Surveying Engineering, China University of Mining & Technology, Beijing, PR China; Tinglu Yang [yang@geology.hk], Faculty of Geosciences, East China University of Technology, Nanchang 330013, PR China; Yuri D. Zakharov [yurizakh@mail.ru], Far East Geological Institute, Far East Branch, Russian Academy of Sciences, Vladivostok, 690022 Russia.