The age of the Kockatea Shale (Lower Triassic), Perth Basin—a reassessment

Abstract

Abstract New evidence for the age of Subinyoites kashmiricus, combined with that of Claraia stachei and Discophiceras sp. cf. D. subkyokticum, has called for a revision in age of the Scythian (Lower Triassic) macrofauna from the Kockatea Shale of Beagle Ridge (BMR 10) Bore. The fauna is now regarded as of Scythian (Gries‐bachian to Smithian) age. Combination of this dating with additional palaeontological evidence from the Perth and Carnarvon Basins: (i) indicates that the base of the Kockatea Shale is markedly different in age in Beagle Ridge (BMR No. 10) Bore, Dongara No. 4, and in outcrop at Mount Minchin and Sugarloaf Hill; (ii) suggests that the Lower Triassic sea was most extensive during the Smithian in the Perth Basin; and (iii) confirms that most of the Locker Shale is younger than the Kockatea Shale.