part-page article on stratigraphic issues

One page article discussing aspects of Australian stratigraphy; this article discusses new unit definitions, ne regional publications and changes to the membership of the Australian Stratigraphy Commission.

Discussion of available stratigraphic resources: the Australian Stratigraphic Units Database (ASUD); documentation of procedures for modifying existing units or establishing new ones; contact details for the Australian Stratigraphy Commission members and ASUD staff. Suggestions on ways of raising awareness through modern media such as a podcast or app, and a request for feedback on what sort of approach might appeal to a university student audience.

part-page item on matters related to the Australian Stratigraphy Commission and the Australian Stratigraphic Units Database. This column explains international connections and reviews several recent relevant articles.

This report was compiled and written to summarise the four-year Palaeovalley Groundwater Project which was led by Geoscience Australia from 2008 to 2012. This project was funded by the National Water Commission's Raising National Water Standards Program, and was supported through collaboration with jurisdictional governments in Western Australia, South Australia and the Northern Territory. The summary report was published under the National Water Commission's 'Waterlines' series. This document is supported by related publications such as the palaeovalley groundwater literature review, the WASANT Palaeovalley Map and associated datasets, and four stand-alone GA Records that outline the detailed work undertaken at several palaeovalley demonstration sites in WA, SA and the NT. Palaeovalley aquifers are relied upon in outback Australia by many groundwater users and help underpin the economic, social and environmental fabric of this vast region. ‘Water for Australia’s arid zone – Identifying and assessing Australia’s palaeovalley groundwater resources’ (the Palaeovalley Groundwater Project) investigated palaeovalleys across arid and semi-arid parts of Western Australia (WA), South Australia (SA) and the Northern Territory (NT). The project aimed to (a) generate new information about palaeovalley aquifers, (b) improve our understanding of palaeovalley groundwater resources, and (c) evaluate methods available to identify and assess these systems.

The upper Permian to Lower Triassic sedimentary succession in the southern Bonaparte Basin represents an extensive marginal marine depositional system that hosts several gas accumulations, including the Blacktip gas field that has been in production since 2009. Development of additional identified gas resources has been hampered by reservoir heterogeneity, as highlighted by preliminary results from a post drill analyses of wells in the study area that identify reservoir effectiveness as a key exploration risk. The sedimentary succession that extends across the Permian–Triassic stratigraphic boundary was deposited during a prolonged marine transgression and shows a transition in lithofacies from the carbonate dominated Dombey Formation to the siliciclastic dominated Tern and Penguin formations. Recent improvements in chronostratigraphic calibration of Australian biostratigraphic schemes, spanning the late Permian and Early Triassic, inform our review of available palynological data and re-interpretation and infill sampling of well data. The results provide a better resolved, consistent and up-to-date stratigraphic scheme, allowing an improved understanding of the timing, duration, and distribution of depositional environments of the upper Permian to Lower Triassic sediments across the Petrel Sub-basin and Londonderry High. <b>Citation:</b> Owens R., Kelman A., Khider K., Iwanec J., Bernecker T. (2022) Addressing exploration uncertainties in the southern Bonaparte Basin: enhanced stratigraphic control and post drill analysis for upper Permian plays. <i>The APPEA Journal</i> 62, S474-S479

This Arafura Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Arafura Basin is a large intracratonic sedimentary basin along the northern continental margin of Australia. Over 90% of the basin occurs offshore in relatively shallow marine waters of the Arafura Sea, with the basin extending northwards beyond Australia's territorial claim. The southern part of the basin is onshore in northern Arnhem Land. Older Paleo- to Mesoproterozoic rocks of the northern Macarthur Basin underlie most of the onshore basin, whereas Mesozoic and Cenozoic sediments of the Money Shoal Basin unconformably overlie the offshore basin. The sedimentary record of the Arafura Basin spans greater than 250 million years, from the late Neoproterozoic to the early Permian. However, subsidence was episodic and restricted to four main phases of regional subsidence interspersed with relatively long periods of tectonic quiescence. Consequently, the entire sedimentary succession of the basin is relatively structurally conformable. The oldest rocks are the Neoproterozoic to Cambrian Wessel Group. These are overlain by the Middle Cambrian to early Ordovician Goulburn Group, followed by the Late Devonian Arafura Group. The uppermost sequence is Late Carboniferous to early Permian (an equivalent of the Kulshill Group from the neighbouring Bonaparte Basin). The sedimentary rocks of the Arafura Basin are clastic-dominated and include sandstone, shale, limestone, dolostone and minor coal and glacial deposits. Most of the Arafura Basin formed within shallow marine environments, with evidence for fluvial conditions largely restricted to the Carboniferous to Permian rocks. There are no detailed basin-scale studies on the hydrogeology and groundwater systems of the Arafura Basin. Previous hydrogeological investigations by the Northern Territory Government during the 1980s and 1990s focused on groundwater supplies for remote communities such as Maningrida, Galiwinku and Millingimbi. Groundwater for these communities is sourced from fractured rock sandstone aquifers, most likely units of the Arafura Basin such as the Marchinbar Sandstone and Elcho Island Formation of the Wessel Group. The aquifers are fractured and extensively weathered up to 100 metres below surface.

Palaeogrographic analysis of the Early Cretaceous South Perth Supersequence.

To test existing geological interpretations and the regional stratigraphic relationships of the Carrara Sub-basin with adjacent resource-rich provinces, the deep stratigraphic drill hole NDI Carrara 1 was located on the western flanks of the Carrara Sub-basin, on the seismic line 17GA-SN1. The recovery of high quality near-continuous core from the Carrara Sub-basin, in concert with the spectrum of baseline analytical work being conducted by Geoscience Australia through the EFTF program, as well as other work by government and university researchers is greatly improving our understanding of this new basin. While recently published geochemistry baseline datasets have provided valuable insight into the Carrara Sub-basin, the age of the sedimentary rocks intersected by NDI Carrara 1 and their chronostratigraphic relationships with adjacent resource rich regions has remained an outstanding question. In this contribution, we present new sensitive high-resolution ion microprobe (SHRIMP) geochronology results from NDI Carrara 1 and establish regional stratigraphic correlations to better understand the energy and base-metal resource potential of this exciting frontier basin in northern Australia.

This Bowen Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Bowen Basin is part of the Sydney–Gunnedah–Bowen basin system and contains up to 10,000 m of continental and shallow marine sedimentary rocks, including substantial deposits of black coal. The basin's evolution has been influenced by tectonic processes initiated by the New England Orogen, commencing with a phase of mechanical extension, and later evolving to a back-arc setting associated with a convergent plate margin. Three main phases of basin development have been identified; 1) Early Permian: Characterized by mechanical extension, half-graben development, thick volcanic units and fluvio-lacustrine sediments and coal deposits. 2) Mid Permian: A thermal relaxation event led to the deposition of marine and fluvio-deltaic sediments, ending with a regional unconformity. 3) Late Permian and Triassic: Foreland loading created a foreland basin setting with various depositional environments and sediment types, including included fluvial, marginal marine, deltaic and marine sediments along with some coal deposits in the late Permian, and fluvial and lacustrine sediments in the Triassic. Late Permian peat swamps led to the formation of extensive coal seams dominating the Blackwater Group. In the Triassic, fluvial and lacustrine deposition associated with foreland loading formed the Rewan Formation, Clematis Sandstone Group, and Moolayember Formation. The basin is a significant coal-bearing region with over 100 hydrocarbon accumulations, of which about one third are producing fields. The Surat Basin overlies the southern Bowen Basin and contains varied sedimentary assemblages hosting regional-scale aquifer systems. Cenozoic cover to the Bowen Basin includes a variety of sedimentary and volcanic rock units. Palaeogene and Neogene sediments mainly form discontinuous units across the basin. Three of these units are associated with small eponymous Cenozoic basins (the Duaringa, Emerald and Biloela basins). Unnamed sedimentary cover includes Quaternary alluvium, colluvium, lacustrine and estuarine deposits; Palaeogene-Neogene alluvium, sand plains, and duricrusts. There are also various Cenozoic intraplate volcanics across the Bowen Basin, including central volcanic- and lava-field provinces.