Radiolaria of middle jurassic to early cretaceous ages from the torlesse complex, eastern tararua range, New Zealand

Abstract

Radiolarians have been successfully extracted from cherts from two localities within the Torlesse Complex of the eastern Tararua Range. Several genera have been identified and these indicate a Middle Jurassic – Early Cretaceous age for the chert from near the Tauherenikau River, and a Late Jurassic – Early Cretaceous age for the chert from the eastern Manawatu Gorge. The radiolarians define the minimum age of oceanic crust upon which the clastic submarine fan-type greywacke and argillite, which make up most of the Torlesse Complex in the eastern Tararua Range, was deposited. The boundary between fossil zones 4 (Monotis and 5 (Late Jurassic – Early Cretaceous) occurs in the central part of the Tararua Range and not to the east of the range, as previously thought. © Crown copyright 1986.