Revision of the Neoproterozoic stratigraphic nomenclature of the Beetaloo Sub-basin, Northern Territory

Abstract

The post-Roper Group stratigraphic succession of the Beetaloo Sub-basin and surrounding areas in the central-northern Northern Territory comprises three formations, two of which have been informally named. These are, in ascending stratigraphic order: the 'Jamison sandstone', the conformably overlying 'Hayfield mudstone', and an unconformably overlying unnamed sandstone formation. A review of the lithological characteristics and age relationships of these units has identified this post-Roper Group succession as a subsurface continuation of the Kiana Group (basal Georgina Basin), which outcrops extensively to the east and southeast of the Beetaloo Sub-basin. The 'Jamison sandstone' and 'Hayfield mudstone' are equated with the Bukalara Sandstone and Cox Formation respectively of the Kiana Group. The latter names have nomenclatorial priority, and therefore the informal names 'Jamison sandstone' and 'Hayfield mudstone' are superceded by the names Bukalara Sandstone and Cox Formation respectively. The name Hayfield Sandstone Member (previously 'Hayfield sandstone member' of the-'Hayfield mudstone') is retained as a member of the Cox Formation. New formal redefinitions of the Kiana Group, Bukalara Sandstone, Cox Formation and Hayfield Sandstone Member are appended.