Conodonts of disparate Lower Devonian zones, Wilson Creek Shale, Tyers-Walhalla area, Victoria, Australia

Abstract

Thin limestone beds are a minor component of the Lower Devonian Wilson Creek Shale in the Tyers-Walhalla area of Victoria. Age-diagnostic conodonts recovered are (1) Eognathodus sulcatus sulcatus, index to the sulcatus Zone (early Pragian), from the Thomson River south of Coopers Creek, and (2) Polygnathus dehiscens, index to the dehiscens Zone (early Emsian), from Jacobs Creek. The Wilson Creek Shale thus ranges from the sulcatus Zone to the dehiscens Zone, and is partly equivalent to the Coopers Creek Limestone (sulcatus Zone). Low-oxygen deposition existed in central Victoria over a considerably longer period in the Early Devonian than previously suspected.