Silurian to basal Devonian conodonts from the Broken River Crossing, northern Australia

WA Museum Records and Supplements | Updated 9 years ago

Abstract - Stratigraphy and conodont biostratigraphy of the Graveyard Creek Group, particularly the Jack Formation, near the Broken River Crossing, northwest of Charters Towers, are described. A minor lenticular limestone within pelitic lithologies near the Crossing, yielded a late Llandovery C5 fauna, consistent with evidence from graptolites. Diagnostic conodonts were obtained from two limestone units in the overlying Jack Formation. The lowest 72 m of the lower of these units is referred to the Ludlow (but not latest Ludlow) ploeckensis and siluricus zones, and correlates broadly with the interval Silverdale Formation to lower Hume Limestone of the Yass Basin, southeastern Australia. The upper unit yielded Icriodus woschmidti hesperius from two localities, which indicates a latest Pridoli-early Lochkov age and provides the possibility of recognising the Silurian-Devonian boundary within the sequence.