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  • Conodont Biostratigraphy of the upper Devonian reef complexes of the Canning Basin, Western Australia

  • Abstract Sedimentary and palaeontological samples from steep, deepwater, escarpments of the Wallaby (`Cuvier') Plateau, a vast marginal plateau with an area of some 100,000km² west of Carnarvon, Western Australia, represent the first collected soft rock geologic data from this immense bathymetric high. The impetus for this frontier, integrated study was to better understand the unresolved geologic history of the Wallaby Plateau, which to date has been hampered by a paucity of real rock data, especially due to difficulties in sampling in 2200 to 5700 m water depths; only modern carbonates, largely altered tholeiitic basalts and volcaniclastic rocks have been recorded previously. Variably fossiliferous to unfossiliferous claystone, siltstone and sandstone samples from 12 southern Wallaby Plateau stations (3015 to 5159 m water depths) range from interpreted paralic to shallow water marine settings, and contain low to moderately diverse assemblages of Bivalvia, Gastropoda, Ostracoda, Foraminifera, palynomorphs, very rare nannofossils, and teleost fish fragments, which collectively point to an age range of latest Berriasian to Barremian-Aptian in the Early Cretaceous that pre-dates, straddles and post-dates the breakup and opening of the Cuvier Abyssal Plain. Seismic imaging of the Wallaby Plateau shows a substantial thickness of both dipping and flat-lying, sub-parallel reflectors beneath parts of the Early Cretaceous Gondwanan break-up unconformity. This information, taken together with the recent identification of Oxfordian-Kimmeridgian foraminifera from the same location, may indicate the presence of pre-breakup sedimentary section beneath parts of the the Wallaby Plateau. Keywords: Systematic palaeontology; Mollusca; Foraminifera; Ostracoda; dinoflagellate cysts; Early Cretaceous; Wallaby Plateau; Australia

  • Legacy product - no abstract available

  • The trilobite faunas described in this Bulletin are exclusively from the Chatsworth Limestone sensu stricto, as it occurs in the immediate neighbourhood of Chatsworth Homestead, 80 km south-southeast of Duchess, in western Queensland (Fig. 1). The outcrops straddle the Duchess and Boulia 1:250000 Sheet areas, and form the central portion of the Burke River Structural Belt (Shergold, 1975, pp. 4-7; in Shergold, Druce et al., 1976, pp. 4-5). "Although trilobites have been described (Opik, 1963, 1967) from the underlying Pomegranate Limestone, at Pomegranate Creek, 19 km north of 'Chatsworth', no material from the Chatsworth Limestone s.s. has been illustrated previously. Those trilobites presently described are from collections made during initial field mapping of the Boulia Sheet area in 1957-60 (Casey, 1968; Casey et al., 1960), and the Duchess area in 1958 (Carter & Opik, 1963; 6pik, 1963). Frome-Broken Hill Pty Ltd collected two samples from the basal Chatsworth Limestone near 'Chatsworth' in 1958 (Taylor, 1959). Subsequently, collections were assembled by the BMR Northwest Queensland Phosphate Group in 1967 (de Keyser et al., in de Keyser, 1968), by the author in 1969, and by B.M. Radke during the course of 1:100 000 scale mapping. by the BMR Georgina Basin Project in 1974-75. Material is also currently. Available from two BMR stratigraphic boreholes, Boulia No. 6 and Duchess No. 13 (Fig. 2 and Appendix 3), drilled for the Georgina Basin Project in 1974. All material described in this Bulletin is deposited in the Commonwealth Palaeontological Collection (prefix CPC), housed in the Bureau of Mineral Resources, Canberra, Australia. Acknowledgements The author acknowledges the time consuming aid given by H.M. Doyle (BMR) in the preparation of the photographs used herein. B.M. Radke (BMR) is thanked for permitting the reproduction of the Lily Creek section which he measured, and J.M. Kennard (BMR) for making available details of cores logged, and for providing petrographic descriptions of the rocks noted in Appendices 1 and 3. I appreciate the constructive criticism provided by Drs R.A. Henderson, James Cook University of North Queensland, and J.B. Jago, South Australian Institute of Technology, on an earlier draft of this Bulletin. The drawings were prepared by R. Fabbo and G. Clarke of BMR's Cartographic Section.