Frasnian conodonts from the Sadler ridge‐Bugle Gap area, Canning Basin, Western Australia

Abstract

Ninety species of conodont are recorded from rocks of Frasnian age in the Bugle Gap area in the Canning Basin of Western Australia: 56 of these species are reported for the first time from the Canning Basin. One new subspecies is described. Two parallel but disparate conodont sequences are present, which are presumed to represent different environments: one, the Palmatolepis sequence of the standard zonation is present in the uppermost beds of the Sadler Limestone at Sadler Ridge, the Gogo Formation, and much but not all of the Virgin Hills Formation, and presumably represents an inter‐reef faunal succession; the other consists of a sequence of Icriodus assemblages which is present in the Sadler Limestone and a part of the Virgin Hills Formation at Lawford Range. An Icriodus zonation is proposed for this sequence. No conodonts were recovered from many samples of the Pillara Limestone (back‐reef facies) in the Bugle Gap area. Conodont data presented here suggest that the Gogo Formation in this area is restricted to the Lower and Middle asymmetricus Zones (to Iα); the upper part of the Sadler Limestone at Sadler Ridge may also be assigned to the Lower and Middle asymmetricus Zones ((to Iα); the Sadler Limestone of the Lawford Range extends through the Lower, Middle and Upper asymmetricus Zones (to Ia — to Iß); and the Virgin Hills Formation extends from the base of the Ancyrognathus triangularis Zone, or just below it (to Iß/γ) through to the velifer Zone (to III). No assumption is made about the applicability of these determinations to outcrops other than those sampled in this study.