David and Pittman (1899) obtained Devonian radiolarians described by Hinde (1899) and revised by Aitchison and Stratford (1997) from the North Tamworth area of NE New South Wales. The host sequence is primarily fine-grained turbidites with minor horizons of debris-flow limestones, arenites, and thin ashfalls. The largest limestone bodies, formerly referred to as the 'Spring Creek limestone', are interpreted as olistoliths of Moore Creeke Limestone emplaced during accumulation of the upper part of the Yarrimie Formation. Because of the demonstrably allochthonous nature of all limestones in the North Tamworth area, the conodont data from these olisoliths and from other limestones in that area are not tightly constraining as to chronology of the associated radiolarian horizons. The limestone horizons on David and Pittman's (1899) transect span an interval from early Emsian to late Frasnian and conceivably as young as the early Famennian-mid Famennian boundary (Late rhomboidea Zone to Early marginifera Zone). The taxonomically useful radiolarians (Aitchison and Stratford 1997) came from three horizons within the upper Yarrimie Formation. These horizons, stratigraphically above the olisoliths of 'Spring Creek limestone' (derived from Moore Creek Limestone, australis to hemiansatus Zones and perhaps Early varcus Subzone: late Eifelian-early Givetian), are argued to be late Givetian (hermanni Zone or younger) and late Frasnian respectively. A broader spectrum of mid-Palaeozoic ages (Pridoli to late Famennian) is indicated by conodonts occurring in association with radiolarians in cherts and siltstones from elsewhere in the region.
|Number of pages||24|
|Journal||Proceedings of the Royal Society of Victoria|
|Publication status||Published - 1997|