Revised terminology of the Late Cambrian - Ordovician sequence of the Florentine - Denison Range area, and the significance of the "Junee Group"

Abstract

The area of Lewis's original "Junee Series" is unsuitable as a basis for definitive stratigraphy and correlation,even with units in adjacent areas. A review of the various usages and concepts associated with the "Junee Group" indicates considerable diversity in meaning and application of the term, and suggests that the sequences are better considered in terms of a lower clastic unit and an upper limestone unit rather than as a single group. Accordingly, the Late Cambrian-Ordovician sequence in the Florentine Synclinorium is defined in terms of the Denison Subgroup, comprising four formations between the basal unconformity on the Denison Range and the base of the limestone, and the Gordon Subgroup, comprising three limestone formations and the Westfield Beds. These two Subgroups together approximate to the "Junee Group".