Age of the Arthur Marble: conodont evidence from Mount Owen, northwest Nelson

Arthur Marble at Mt Owen forms a 6 + 10 km massif of recumbently folded limestone. The limestone is overlain in the Nuggety Creek area by Wangapeka Formation shales bearing Eastonian graptolites. Llandeilo (late Darriwilian to early Gisbornian) and possible late Llanvirn conodonts are here recorded from the upper beds of the limestone, providing the first evidence of limestone deposition during the Middle Ordovician in New Zealand.