Silurian of Australia and New Guinea : biostratigraphic correlations and paleogeography

The Silurian of Australia, illustrated herein by 33 stratigraphic columns, is correlated by conodonts and graptolotes. The consequences of such correlations in understanding transgression-regression patterns and changes in paleogeography are synthesized. Biostratigraphic correlations allow a dozen new conclusions on the Australia Silurian. 1) The Silurian of eastern Victoria (earlier regarded as Late Silurian) includes almost all of the upper Llandovery (Pterospathodus celloni Zone)-Pridoli. 2) The Sardine Conglomerate of eastern Victoria probably reflects earliest Devonian synorogenic sedimentation. 3) The Yass sequence seems to extend down into the upper Wenlock. 4) The Canberra succession is likely mainly Ludlow, rather than Wenlock. 5) The Silurian of the northern Capertee High extends well down into the Wenlock. 6) The two major units of the northern Molong Arch (Nandillyan and Narragal Limestones) are appreciably different in age (early Wenlock and late Ludlow, respectively). 7) late Ludlow-Pridoli siliciclastics at the base of the Winduck Formation extend west into the Darling Basin and Bancannia Trough, western New South Wales. 8) Silurian clasts appear at six localities in the Tamworth Belt, northern New South Wales; this implies substantial platform carbonates to the west. 9) The Pridoli-Lochkovian is absent in the Calliope Arc of east-central Queensland except at Craiglee. 10) Sequences from the Camel Creek Province of northern Queensland yield mixed Ashgillian and Llandovery-earliest Wenlock conodonts that show cannibalization of shelf platform carbonates to the west and/or southwest, a region where autochthonous pre-Pterospathodus amorphognathoides Zone (Llandovery) carobontes are unknown in the Broken River and Camel Creek Provinces. 11) An apparently unbroken sequence exists from the Pterospathodus celloni Zone (and possibly older horizons) through the Lower Devonian in the Hodgkinson Province of northeast Queensland. 12) Improved biostratigraphic control is possible on evaporates in the Carnarvon (Llandovery-Pridoli) and Canning basins (middle Llandovery and older). Improved biostratigraphic precision, particularly for the latter two areas have resulted in revised timing of the transgression-regression pattern. The new data, especially from the Indi and upper Buchan River areas of eastern Victoria, are consistent with the main events of the Benambran cycle (arguably the most profound Phanerozoic orogenic cycle in Australia). This orogeny occurred in the late(?) Ashgillian to early or middle Llandovery, rather than in a generalized Llandovery-Wenlock interval, as earlier assumed.39 page(s