Revisiting Upper Permian Stratigraphy, Northern Perth Basin, Western Australia

New palynological processing of core from UWA 4 drilled in 1964 adjacent to outcrop of the non-marine Wagina Sandstone near the Darling Fault on the Irwin Terrace of the northern Perth Basin yielded spores and pollen of the mid-Roadian Microbaculispora villosa Zone. However, this formation name has also been applied to shallow-marine facies containing spore-pollen of the Wordian to Changhsingian Didecitriletes ericianus to Dulhuntyispora parvithola zones in petroleum exploration wells within the western part of the basin. Not only are these zones significantly younger, but in that part of the basin the M. villosa Zone is restricted to the unconformably underlying Kungurian Carynginia Formation. That hiatus spans at least the late Roadian to early Wordian Dulhuntyispora granulata Zone whereas in outcrop along the Irwin Terrace the Wagina Sandstone appears to be conformable on the Carynginia Formation. Despite these differences and the name Wagina Sandstone having historical precedence for the outcrop, its overwhelming application in the subsurface is given priority to avoid confusion. Accordingly, the outcrops next to the Darling Fault are renamed as ‘Ebano Sandstone’. Other upper Permian subsurface units are retained: Dongara Sandstone for shoreface facies overlying the Wagina Sandstone, and Beekeeper Formation for the dominantly sandy carbonate facies in the south. Nevertheless, these three units interfinger such that differentiating them can be subjective. By comparison, none of the names listed above are appropriate for the upper Permian non-marine sections east of Geraldton in the north of the basin near Eradu and Indarra.