Palaeogrographic analysis of the Early Cretaceous South Perth Supersequence.

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.

The Australian Government, through the National Water Infrastructure Fund – Expansion, commissioned Geoscience Australia (GA) to undertake the project ‘Assessing the Status of Groundwater in the Great Artesian Basin’ (GAB). The project commenced in July 2019 and will finish in June 2022. The aim of the project is to develop and evaluate new tools and techniques to assess the status of GAB groundwater system to support responsible management of basin water resources. A critical relationship exists between sediment depositional architecture and groundwater flow within and between GAB aquifers, and their connectivity with underlying and overlying aquifers. Little is known about lateral and vertical facies variation within the hydrogeological units and potential compartmentalisation and connectivity across the GAB. To improve the understanding of distribution and characteristics of Jurassic and Cretaceous sediments across the Eromanga/Galilee/Surat basins region, GA is compiling, processing and correlating a variety of well log data. Correlations have been made between geological units of similar age using palynological data from 322 key wells along 28 regional transects to standardise lithostratigraphic units, which are currently described using varying nomenclature, to a single chronostratigraphic chart across the entire GAB. The distribution of generalised sand/shale ratios calculated for 236 wells in the Surat and Eromanga basins are used to estimate the thickness of sand and shale in the different formations, with implications for formation porosity and the hydraulic properties of aquifers and aquitards. This study highlights regional lithological heterogeneity in each hydrogeological unit, and contributes to our understanding of connectivity within and between aquifers. This report and associated data package provide a first phase of data compilation on 322 key wells in the Surat and Eromanga basins to assist in updating the geological framework for the GAB. A data gap analysis and recommendations for building on this initial work are also provided.

One page article discussing aspects of Australian stratigraphy; this article discusses practical Australian solutions to igneous nomenclature and the indexing of relevant Antarctic units

This Central Australian Cenozoic Basins 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. Cenozoic basins are an important source of readily accessible groundwater within the arid deserts of central Australia. This province represents a collection of six notable Cenozoic basins within the region, including the Ti Tree, Waite, Hale, Mount Wedge, Lake Lewis and Alice Farm basins. Many local communities in this region (such as Papunya, Ti Tree and Ali Curung) rely upon groundwater stored within Cenozoic basin aquifers for their water security. The basins typically contain up to several hundred metres of saturated sediments that can include relatively thick intervals of hydraulically conductive sands, silts and minor gravels. It is noted that the potential groundwater storage volumes in the Cenozoic basins are much greater than the annual amount of runoff and recharge that occurs in central Australia, making them prospective targets for groundwater development. Groundwater quality and yields are variable, although relatively good quality groundwater can be obtained at suitable yields in many areas for community water supplies, stock and domestic use and irrigated horticulture operations, for example, in the Ti Tree Basin. However, not all of the Cenozoic basins have the potential to supply good quality groundwater resources for community and horticultural supplies. With the exception of several small sub-regions, most of the Waite Basin has very little potential to supply good quality groundwater for agricultural use. This is mainly due to limited aquifer development, low yielding bores and elevated groundwater salinity (commonly >2000 mg/L Total Dissolved Solids). However, bores have been successfully installed for smaller-scale pastoral stock and domestic supplies and small communities or outstations in the Waite Basin.

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.

This Port Phillip-Westernport 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 Port Phillip and Westernport basins are small, shallow sedimentary basins located in south-central Victoria, formed during the Late Cretaceous rifting of Australia and Antarctica. They share similar stratigraphy with nearby basins. The Port Phillip Basin is bounded by the Selwyn and Rowsley Faults to the east and west, while the Heath Hill Fault marks the eastern boundary of the Westernport Basin. Both basins have pre-Cenozoic basement rocks comprising folded and faulted Paleozoic metasedimentary rocks and granites from the Lachlan Fold Belt. The Port Phillip Basin's stratigraphy includes Maastrichtian to Cenozoic sedimentary units with intercalated volcanic rocks. The main depocentres are the Sorrento Graben, Ballan Graben/Lal Lal Trough, and Parwan Trough. Notable formations are the Yaloak and Werribee formations, with coal-bearing strata and marine sediments. The Westernport Basin has coastal sediments and volcanic deposits from Paleocene to Holocene. It experienced marine transgressions and regressions due to sea-level fluctuations. Fault movements in the late Pliocene and early Pleistocene formed a fault-bounded depression centered on the Koo Wee Rup Plain. The main units are the Childers Formation, Older Volcanics, Yallock Formation, Sherwood Marl, and Baxter Sandstone. Both basins have Quaternary sediments, including Pleistocene eolian sand sequences, Holocene alluvial and paludal clays, and fluvial sediments in valleys and palaeovalleys. The Port Phillip Basin contains distinct phases of terrestrial and marine deposition, while the Westernport Basin has Eocene volcanism and marine sediments. These basins are important geological features in the region, with various formations representing millions of years of geological history.

This Georgina 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 Georgina Basin is a large intra-cratonic sedimentary basin in central Australia that has undergone several deformation events throughout its geological history. Its deposition began during the Neoproterozoic due to the breakup and erosion of the Rodinia Supercontinent, resulting in the broader Centralian Superbasin, encompassing the Amadeus, Georgina, Ngalia, Officer, and Savory basins. The basin's initial formation occurred as a north-west trending extensional structure in its southern part, containing thick sequences preserved in structural depo-centres such as the Toko Syncline, Dulcie Syncline, and Burke River Structural Zone. The basin unconformably overlies Proterozoic basement rocks, with its eastern boundary onlapping the Mesoproterozoic Mount Isa Province. The Georgina Basin is connected to the Daly and Wiso basins by early to middle Cambrian seaways in some areas, while in others, they are separated by basement highs like the Tomkinson, Warramunga, and Davenport provinces. The northern Georgina Basin is overlain by Mesozoic rocks of the Carpentaria Basin, and the southern basin is covered by Cenozoic deposits. The stratigraphy and rock types within the Georgina Basin include Neoproterozoic rock units in the southern parts correlated with the Centralian Superbasin, characterized by dolostone, tillite, sandstone, quartzite, siltstone, conglomerate, and shale. The basin's structure has been moderately deformed by folding and faulting, with the most significant deformation in its southern part related to the Ordovician to Carboniferous Alice Springs Orogeny. The basin's development occurred in several stages, including Neoproterozoic rifting and subsidence, tectonic activity during the Petermann Orogeny, Early Cambrian rifting, Middle to late Cambrian foreland loading and deposition, Early Ordovician minor rifting, transpression during the Alice Springs Orogeny, and a final phase of synorogenic siliclastic sedimentation in a foreland basin setting, is limited to southern depo-centres. Overall, the Georgina Basin's complex geological history has resulted in a diverse array of sedimentary rocks and structural features, making it a significant area of interest for geological studies and resource exploration in central Australia.

This Perth 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 Perth Basin is a complex geological region extending along Australia's southwest margin for about 1,300 km. It comprises sub-basins, troughs, terraces, and shelves, hosting sedimentary rocks with coal, oil, gas, and significant groundwater resources. Off the coast of Western Australia, it reaches depths of up to 4,500 m, while its onshore part extends up to 90 km inland. The basin is bounded by the Yilgarn Craton to the east, and the Carnarvon and Bremer basins to the north and south. The basin's history involves two main rifting phases in the Permian and Late Jurassic to Early Cretaceous, creating 15 sub-basins with varying sedimentary thickness due to compartmentalization and fault reactivation. The sedimentary succession mainly comprises fluviatile Permian to Early Cretaceous rocks over Archean and Proterozoic basement blocks. Differences exist between northern and southern sequences, with the south being continental and the north featuring marine deposits. During the Permian, faulting and clastic sedimentation dominated, with marine transgressions in the north and continental rocks in the south. The Triassic saw a similar pattern, with the southern succession being continental and the northern succession showing marine deposits. The Kockatea Shale became a primary hydrocarbon source. The Jurassic period witnessed marine incursions in the central basin, while the Late Jurassic experienced sea level regression and deposition of the Yarragadee Formation. The Cretaceous saw the formation of the Early Cretaceous Parmelia Group due to heavy tectonic activity. The southern basin had a marine transgression leading to the Warnbro Group's deposition with valuable groundwater resources. Post-Cretaceous, Cenozoic deposits covered the basin with varying thicknesses. Overall, the Perth Basin's geological history reveals a diverse sedimentary record with economic and resource significance.