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A correlation chart for the Triassic System in Australia is presented. The base of the System in Australia is taken as the earliest occurrence of the Lunatisporites pellucidus Assemblage Zone in a section of the Rewan Formation in the Bowen Basin, Queensland, and the base of the Jurassic System as the occurrence of Ceratosporites helidonensis with ClassopoWs and Retitriletes austroclavatitides in the Upper Woogaroo Subgroup in a section near Ipswich in the Moreton Basin. Correlations within Australia are based predominantly on microfioral evidence with supporting evidence from fossil vertebrates and, to a minor degree, on macrofiora. Correlation of Australian units with those in other continents depends on ammonites, bivalves, conodonts, vertebrates, and microfiora in Lower Triassic units; and on vertebrates and microfiora in higher units. A cross-indexed bibliography on the Triassic System in Australia covering 21 years to the end of 1973 is also provided.

Drastic changes in ideas of the age of some of the marine Tertiary deposits in Australia have been necessary in the last few years. The recognition of Eocene over a wide area in south-eastern Australia is the result of considerable detailed mapping of deposits in south-western Victoria and the subsequent detailed investigation of the sediments for microfaunas. The discovery of the Eocene foraminiferal genus Hantkenina at different localities in south-eastern Australia has been an important factor in bringing about the recognition of the Eocene. The discovery of Hantkenina at Bird Rock, Torquay, Victoria, the type locality for the Janjukian Stage of Victorian Tertiary stratigraphy, confirms an Eocene age for beds which had previously been placed in the Upper Oligocene or the Miocene. The type section for the "Anglesean Stage" at Anglesea, west of Torquay, which has been regarded as Oligocene, is now placed in the Middle Eocene. The beds at Anglesea stratigraphically underlie those containing Hantkenina at Torquay. At least 4,000 feet of the Middle Eocene beds have been proved in bores. In western Victoria it is quite probable that Lower Eocene to Paleocene beds exist. There is still doubt as to whether definite marine Oligocene beds exist in Australia. Certain non-marine deposits thought to be of Lower Oligocene age are now Middle Miocene. Ideas of age of the beds in the Upper Tertiary have undergone little change. The calcareous sandstones of the Adelaide Basin in South Australia are regarded as Lower Pliocene rather than Middle or Upper Pliocene of certain authors.

The pocket in this Bulletin contains five Australia-wide correlation charts and location maps in microform (together with microform of the Bulletin text). The charts summarize the stratigraphy of the major Australian basins that belong to two categories in the Tectonic Map Map of Australia and New Guinea (1971) Trans- Australian Platform Cover and Central Australian Platform Cover. Several basins belonging to Transitional Domains have also been included because one of them (Adavale Basin) contains hydrocarbons. The platform cover in Australia that is Adelaidean to Recent in age can be studied in five major time-rock groupings, each of which forms the basis of one of the charts. These groupings are clearly similar to the 'megasequences' described by J. W. Porter and R. G. McRossan for the Phanerozoic of Canada and which appear to have worldwide significance and seem to conform to major events preceding and following the breakup of Pangaea (Basin consanguinity in petroleum resource estimation. In Haun, J. D. (Ed.), Studies in Geology No. I-Methods of estimating the volume of undiscovered oil and gas resources. Amer. Ass. petrol. Geol., Tulsa, 1975). An attempt has been made to show the lithology, maximum thickness and environment of deposition of the various beds listed. Estimates of hydrocarbon reserves are as quoted in BMR Petroleum Newsletter No. 62 (1975). A wide range of published stratigraphic correlations and interpretations has been used in the compilation. No rigid interpretation of age or equivalence of strata should necessarily be presumed by the layout of the data in the charts. Brief notes on the major time-rock groupings follow, together with selected bibliographies.

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available

Legacy product - no abstract available