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  • 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.

  • This Carnarvon 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 Carnarvon Basin is a large sedimentary basin covering the western and north-western coast of Western Australia, stretching over 1,000 km from Geraldton to Karratha. It is predominantly offshore, with over 80% of the basin located in water depths of up to 4,500 m. The basin is elongated north to south and connects to the Perth Basin in the south and the offshore Canning Basin in the north-east. It is underlain by Precambrian crystalline basement rocks. The Carnarvon Basin consists of two distinct parts. The southern portion comprises onshore sub-basins with mainly Paleozoic sedimentary rocks extending up to 300 km inland, while the northern section consists of offshore sub-basins containing Mesozoic, Cenozoic, and Paleozoic sequences. The geological evolution of the Southern Carnarvon Basin was shaped by multiple extensional episodes related to the breakup of Gondwana and reactivation of Archean and Proterozoic structures. The collision between Australia and Eurasia in the Mid-Miocene caused significant fault reactivation and inversion. The onshore region experienced arid conditions, leading to the formation of calcrete, followed by alluvial and eolian deposition and continued calcareous deposition offshore. The Northern Carnarvon Basin contains up to 15,000 m of sedimentary infill, primarily composed of siliciclastic deltaic to marine sediments from the Triassic to Early Cretaceous and shelf carbonates from the Mid-Cretaceous to Cenozoic. The basin is a significant hydrocarbon province, with most of the resources found within Upper Triassic, Jurassic, and Lower Cretaceous sandstone reservoirs. The basin's development occurred during four successive periods of extension and thermal subsidence, resulting in the formation of various sub-basins and structural highs. Overall, the Carnarvon Basin is a geologically complex region with a rich sedimentary history and significant hydrocarbon resources. Exploration drilling has been ongoing since 1953, with numerous wells drilled to unlock its hydrocarbon potential.

  • This Southern Australian Fractured Rock Province 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. Crustal elements are crustal-scale geological regions primarily based on composite geophysical domains, each of which shows a distinctive pattern of magnetic and gravity anomalies. These elements generally relate to the basement, rather than the sedimentary basins. The South Australian Element comprises the Archean-Mesoproterozoic Gawler Craton and Paleo-Mesoproterozoic Curnamona Province, formed over billions of years through sedimentation, volcanism, magmatism, and metamorphism. The region experienced multiple continental-continent collisions, leading to the formation and breakup of supercontinents like Nuna and Rodinia, along with periods of extensional tectonism. Around 1,400 Ma, both the Gawler Craton and Curnamona Province were cratonised, and during the building of the Rodinia supercontinent (1,300-700 Ma), the present configuration of the region emerged. The area between the Gawler and Curnamona provinces contains Neoproterozoic to Holocene cover, including the Adelaide Superbasin, with the Barossa Complex as its basement, believed to be part of the Kimban Orogen. The breakup of Rodinia in the Neoproterozoic (830-600 Ma) resulted in mafic volcanism and extensional episodes, leading to the formation of the Adelaide Superbasin, characterized by marine rift and sag basins flanking the Gawler Craton and Curnamona Province. During the Mesozoic and Cenozoic, some tectonic structures were rejuvenated, while sedimentary cover obscured much of the now flatter terrain. Metamorphic facies in the region vary, with the Gawler and Curnamona provinces reaching granulite facies, while the Adelaide Superbasin achieved the amphibolite facies. The Gawler Craton contains rocks dating back to approximately 3,150 Ma, while the Curnamona Province contains rocks from 1,720 to 1,550 Ma. These ancient regions have undergone various deformation and metamorphic events but have remained relatively stable since around 1,450 Ma. The Adelaide Superbasin is a large sedimentary system formed during the Neoproterozoic to Cambrian, with distinct provinces. It started as an intracontinental rift system resulting from the breakup of Rodinia and transitioned into a passive margin basin in the southeast and a failed rift in the north. Later uplift and re-instigated rifting led to the deposition of thick Cambrian sediments overlying the Neoproterozoic rocks. Overlying basins include late Palaeozoic to Cenozoic formations, such as the Eromanga Basin and Lake Eyre Basin, which are not part of the assessment region but are adjacent to it.

  • Geoscience Australia has undertaken a regional seismic mapping study that extends into the frontier deep-water region of the offshore Otway Basin. This work builds on seismic mapping and petroleum systems modelling published in the 2021 Otway Basin Regional Study. Seismic interpretation spans over 18 000 line-km of new and reprocessed data collected in the 2020 Otway Basin seismic program and over 40 000 line-km of legacy 2D seismic data. Fault mapping has resulted in refinement and reinterpretation of regional structural elements, particularly in the deep-water areas. Structure surfaces and isochron maps highlight Shipwreck (Turonian–Santonian) and Sherbrook (Campanian–Maastrichtian) supersequence depocentres across the deep-water part of the basin. These observations will inform the characterisation of petroleum systems within the Upper Cretaceous succession, especially in the underexplored deep-water region. Presented at the 2022 Australian Petroleum Production & Exploration Association (APPEA)

  • 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. Of these, the Blacktip gas field has been in production since 2009, while additional identified gas resources are under consideration for development. The sedimentary succession extends across the Permian–Triassic stratigraphic boundary, and shows a change in lithofacies changes from the carbonate dominated Dombey Formation to the siliciclastic dominated Tern and Penguin formations. The timing, duration, distribution and depositional environments of these formations in the Petrel Sub-basin and Londonderry High is the focus of this study. The sedimentary succession extending from the Dombey to the Penguin formations is interpreted to represent marginal marine facies which accumulated during a long-lasting marine transgression that extended over previous coastal and alluvial plain sediments of the Cape Hay Formation. The overlying Mairmull Formation represents the transition fully to marine deposition in the Early Triassic. Regional scale well correlations and an assessment of available biostratigraphic data suggest marginal marine deposition systems were initiated outboard before the End Permian Extinction event, subsequently migrated inboard at about the Permian–Triassic stratigraphic boundary, and continued to be deposited through the faunal and floral recovery phase as Triassic species became established. The depositional history of the basin is translated to a chronostratigraphic framework which has implications for predicting the character and distribution of petroleum system elements in the Petrel Sub-basin and Londonderry High. Appeared in The APPEA Journal 61(2) 699-706, 2 July 2021

  • This Surat 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 Surat Basin is a sedimentary basin with approximately 2500 m of clastic fluvial, estuarine, coastal plain, and shallow marine sedimentary rocks, including sandstone, siltstone, mudstone, and coal. Deposition occurred over six cycles from the Early Jurassic to the Cretaceous, influenced by eustatic sea-level changes. Each cycle lasted 10 to 20 million years, ending around the mid-Cretaceous. Bounded by the Auburn Arch to the northeast and the New England Orogen to the southeast, it connects to the Clarence-Moreton Basin through the Kumbarilla Ridge. The Central Fold Belt forms its southern edge, while Cenozoic uplift caused erosion in the north. The basin's architecture is influenced by pre-existing faults and folds in the underlying Bowen Basin and the nature of the basement rocks from underlying orogenic complexes. Notable features include the north-trending Mimosa Syncline and Boomi Trough, overlying the deeper Taroom Trough of the Bowen Basin and extending southwards. The Surat Basin overlies older Permian to Triassic sedimentary basins like the Bowen and Gunnedah Basins, unconformably resting on various older basement rock terranes, such as the Lachlan Orogen, New England Orogen, and Thomson Orogen. Several Palaeozoic basement highs mark its boundaries, including the Eulo-Nebine Ridge in the west and the Kumbarilla Ridge in the east. Paleogene to Neogene sediments, like those from the Glendower Formation, cover parts of the Surat Basin. Remnant pediments and Cenozoic palaeovalleys incised into the basin have added complexity to its geological history and may influence aquifer connections. Overall, the Surat Basin's geological history is characterized by millions of years of sedimentation, tectonic activity, and erosion, contributing to its geological diversity and economic significance as a source of natural resources, including coal and natural gas.

  • 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.

  • This Officer 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 Officer Basin is one of Australia's largest intra-cratonic sedimentary basins, spanning approximately 525,000 square kilometres. It contains a thick sedimentary sequence, ranging up to 10,000 m in depth, composed of rocks from the Neoproterozoic to Late Devonian periods. The basin features diverse depositional environments, including marine and non-marine siliclastic and carbonate units, evaporites, and minor volcanic deposits. The Neoproterozoic succession exhibits a range of depositional settings, including pro-delta to shelf, fluvial to shallow marine, lagoonal, glacial, and aeolian systems. The Cambrian to Ordovician sequence reveals evidence of fluvial, shallow marine, aeolian, sabkha to playa, and lacustrine settings. Volcanic rocks occur sporadically within the sequence, like the Cambrian Table Hill Volcanics in WA and the Neoproterozoic Cadlareena Volcanics in SA. The Officer Basin is considered a remnant of the larger Centralian Superbasin that formed during the Neoproterozoic, covering a vast region in central Australia. The Centralian Superbasin formed as a sag basin during the Tonian, accumulating fluvial, marine, and evaporitic sediments, followed by Neoproterozoic glacial deposits. The long-lasting Petermann Orogeny affected the earlier depositional systems, with extensive uplift along the northern margin of the basin leading to deposition of widespread fluvial and marine siliciclastic and carbonate sediments spanning the terminal Proterozoic to Late Cambrian. The Delamerian Orogeny renewed deposition and reactivated existing structures, and promoted extensive basaltic volcanism in the central and western regions of the basin. Later events are a poorly understood stage, though probably involved continued deposition until the Alice Springs Orogeny uplifted the region, terminating sedimentation in the Late Ordovician or Silurian. A suspected Late Devonian extensional event provided space for fluvial siliciclastic sediment deposition in the north-east. Today, the Officer Basin features four distinct structural zones: a marginal overthrust zone along the northern margin, a zone with rupturing by salt diapirs across the main depositional centre, a central thrusted zone, and a broad gently dipping shelf zone that shallows to the south.

  • This Sydney 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 Sydney Basin, part of the Sydney–Gunnedah–Bowen basin system, consists of rocks dating from the Late Carboniferous to Middle Triassic periods. The basin's formation began with extensional rifting during the Late Carboniferous and Early Permian, leading to the creation of north-oriented half-grabens along Australia's eastern coast. A period of thermal relaxation in the mid Permian caused subsidence in the Bowen–Gunnedah–Sydney basin system, followed by thrusting of the New England Orogen from the Late Permian through the Triassic, forming a foreland basin. Deposition in the basin occurred in shallow marine, alluvial, and deltaic environments, resulting in a stratigraphic succession with syn-depositional folds and faults, mostly trending north to north-east. The Lapstone Monocline and Kurrajong Fault separate the Blue Mountains in the west from the Cumberland Plain in the central part of the basin. The Sydney Basin contains widespread coal deposits classified into geographic coalfield areas, including the Southern, Central, Western, Newcastle, and Hunter coalfields. These coalfields are primarily hosted within late Permian strata consisting of interbedded sandstone, coal, siltstone, and claystone units. The coal-bearing formations are grouped based on sub-basins, namely the Illawarra, Tomago, Newcastle, and Wittingham coal measures, underlain by volcanic and marine sedimentary rocks. Deposition within the basin ceased during the Triassic, and post-depositional igneous intrusions (commonly of Jurassic age) formed sills and laccoliths in various parts of the basin. The maximum burial depths for the basin's strata occurred during the early Cretaceous, reaching around 2,000 to 3,000 metres. Subsequent tectonic activity associated with the Tasman Rift extension in the Late Cretaceous and compressional events associated with the convergence between Australia and Indonesia in the Neogene led to uplift and erosion across the basin. These processes have allowed modern depositional environments to create small overlying sedimentary basins within major river valleys and estuaries, along the coast and offshore, and in several topographic depressions such as the Penrith, Fairfield and Botany basins in the area of the Cumberland Plain.

  • This South Nicholson 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. This South Nicholson 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 South Nicholson Basin is a Mesoproterozoic sedimentary basin spanning Queensland and the Northern Territory and is bordered by neighbouring provinces and basins. The basin unconformably overlies the Lawn Hill Platform of the Mount Isa Province to the east, is bound by the Warramunga and Davenport provinces to the south-west, the Murphy Province to the north and the McArthur Basin to the north-west. It extends southwards under younger cover sequences. Rock units in the basin are correlated with the Roper Group in the McArthur Basin, forming the 'Roper Superbasin.' The underlying Mount Isa Province contains potential shale gas resources. The basin mainly consists of sandstone- and siltstone-bearing units, including the South Nicholson Group, with a prevailing east to east-northeast structural grain. Mild deformation includes shallowly plunging fold axes and numerous faults along a north-west to south-east shortening direction. Major geological events affecting the South Nicholson Basin region include the formation of the Murphy Province's metamorphic and igneous rocks around 1850 million years ago (Ma). The Mount Isa Province experienced deposition in the Leichhardt Superbasin (1800 to 1750 Ma) and Calvert Superbasin (1725 to 1690 Ma). The Isa Superbasin, with extensional growth faulting in the Carrara Sub-basin (~1640 Ma), deposited sediments from approximately 1670 to 1590 Ma. Subsequently, the South Nicholson Group was deposited around 1500 to 1430 Ma, followed by the Georgina Basin's sedimentation. The basin shows potential for sandstone-type uranium, base metals, iron ore, and petroleum resources, while unconventional shale and tight gas resources remain largely unexplored. The Constance Sandstone holds promise as a petroleum reservoir, and the Mullera Formation and Crow Formation serve as potential seals.