This Otway 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 Otway Basin is an elongated sedimentary basin located on the south-east continental margin of Australia. Covering approximately 150,000 square kilometres and stretching about 500 km from South Australia's Cape Jaffa to Victoria's Port Phillip Bay and Tasmania's north-west, most of the basin is offshore, with a smaller portion onshore. Geological studies of the Otway Basin have primarily focused on its hydrocarbon prospectivity, examining thick Cretaceous aged rocks both onshore and offshore. However, the shallower onshore sedimentary units are more relevant from a groundwater perspective. The basin's formation began with rifting between the Australian and Antarctic plates during the Late Jurassic, leading to regional subsidence and the development of the elongated sedimentary basin. Following the Cretaceous plate breakup, a passive margin basin formed, which subsequently underwent basin inversion, reverse faulting, and folding, interspersed with extensional periods and normal faulting. This complex evolution, combined with sea level variations and volcanic activity, resulted in numerous sedimentary cycles. The sedimentary succession in the basin comprises non-marine sediments and volcanic rocks from the Jurassic and early Cretaceous, with a period of tectonic compression interrupting sedimentation during the mid-Cretaceous. The late Cretaceous and Cenozoic sedimentary and volcanic rocks form the primary groundwater-bearing aquifers of the basin, with various sedimentary environments developing in the Neogene and Quaternary. The basin's structural geology is intricate, with numerous basement highs, sub-basins, troughs, and embayments. Fault systems are prevalent, separating tectonic blocks and potentially influencing groundwater flow, offering conduits for inter-aquifer connectivity. Overall, the Otway Basin's geological history has shaped its hydrocarbon potential and groundwater resources, making it an essential area for ongoing research and exploration in Australia's geological landscape.

This North-east 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. In fractured rock aquifers, groundwater is stored in the fractures, joints, bedding planes and cavities of the rock mass. About 40 per cent of groundwater in Australia is stored in fractured rock aquifers, and much of this may be available for irrigation, town water supplies, stock watering and domestic use. Approximately 33% of all bores in Australia are in fractured systems, representing about 10 per cent of total extraction. Groundwater yield is extremely variable, and dependent on the distribution of major fractures. However, rates of groundwater movement in fractured rock systems are difficult to quantify. Characterising groundwater flow in fractured rock aquifers is difficult with existing techniques, and groundwater flow direction can be related more to the orientation of fractures than to the hydraulic head distribution. Recharge in fractured rock aquifers is usually local and intermediate. The Queensland fractured rock is taken to be that part of the northern elements of the Eastern Fracture Rock provinces that extends from the southern part of the Laura Basin, south to the state boundary with New South Wales, and inland as far as the Bundock and Galilee Basins. It comprises the Mossman, Thomson and New England Orogens, and related Provinces. These include: i) The Mossman Orogen, including the Hodgkinson Province, and the Broken River Province; ii) The Thomson Orogen, comprising Neoprotozoic – Early Paleozoic Provinces, including the Anakie Province, Barnard Province, Charters Tower Province, Greenvale Province, and Iron Range Province; and iii) The New England Orogen, including the Gympie Province, Connors-Auburn Province, Yarrol Province, Wandilla Province, Woolomin Province, Calliope Province, Marlborough Province, and Silverwood Province

Discussion of the uses made of the Australian Stratigraphic units database (ASUD), the sources of data to update it, and issues with maintaining quality. The importance of correct and consistent terminology, and the value of good reviews and editing are highlighted with examples.

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 Eromanga 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 Eromanga Basin, part of the Great Artesian Basin (GAB) in Australia, is an extensive Mesozoic sedimentary basin filled with a mix of non-marine and marine rocks. The GAB covers about 22% of the Australian land surface, including areas in Queensland, New South Wales, South Australia, and the Northern Territory. The Eromanga Basin is the largest among the basins that form the GAB. Spanning over 1,250,000 square kilometres in central and eastern Australia, the Eromanga Basin contains rocks ranging from Jurassic to Cretaceous in age. The sedimentary deposits consist of three main basin successions: Early Jurassic to Early Cretaceous fluvial and lacustrine, Early to mid-Cretaceous marine, and Late Cretaceous fluvial-lacustrine successions. The basin's stratigraphic architecture results from a complex interplay between subsidence-controlled accommodation, sediment supply rates, and changing sediment provenance. These controls were influenced by various factors, such as intra-plate stress fields, eustatic sea-level fluctuations, and dynamic mantle-driven topography during the breakup of the Gondwana supercontinent. During the Jurassic and Early Cretaceous, regional uplift of the Australian continent led to an influx of fluvial sand-rich sediments in the western Eromanga Basin. Subsequent rapid subsidence and global high sea levels during the Early Cretaceous allowed marine sediments to spread across much of Australia, including the Eromanga Basin. The basin later returned to non-marine sedimentation during the Late Cretaceous with deposition of the Winton Formation, followed by closure due to an east-directed Late Cretaceous compressional event. This rapid deposition of the Late Cretaceous Winton Formation played a crucial role in generating and expelling hydrocarbons from various source intervals. The movement of the Australian continent significantly impacted the basin, causing most tectonic activity to occur on the southern side of a prominent keel near Innamincka in the southern half of the GAB. Additionally, variations in the mechanical properties of the sub-lithospheric mantle affected stress distribution, leading to changes in surface elevation and the expression of discharge from aquifers, potentially influencing the location and pattern of spring sites within the South Australian part of the GAB.

The advent of Chemical Abrasion-Isotope Dilution Thermal Ionisation Mass Spectrometry (CA-IDTIMS) has revolutionised U-Pb dating of zircon, and the enhanced precision of eruption ages determined on volcanic layers within basin successions permits an improved calibration of biostratigraphic schemes to the numerical timescale. The Guadalupian and Lopingian (Permian) successions in the Sydney, Gunnedah, Bowen and Canning basins are mostly non-marine and include numerous airfall tuff units, many of which contain zircon. The eastern Australian palynostratigraphic scheme provides the basis for much of the local correlation, but the present calibration of this scheme against the numerical timescale depends on a correlation to Western Australia, using rare ammonoids and conodonts in that succession to link to the standard global marine biostratigraphic scheme. High-precision U¿Pb zircon dating of tuff layers via CA-IDTIMS allows this tenuous correlation to be circumvented¿the resulting direct calibration of the palynostratigraphy to the numerical timescale highlights significant inaccuracies in the previous indirect correlation. The new data show: the top of the Praecolpatites sinuosus (APP3.2) Zone lies in the early Roadian, not the middle Kungurian; the top of the Microbaculispora villosa (APP3.3) Zone lies in the middle Roadian, not the early Roadian; the top of the Dulhuntyispora granulata (APP4.1) Zone lies in the Wordian, not in the latest Roadian; the top of the Didecitriletes ericianus (APP4.2) Zone lies in the first half of the Wuchiapingian, not the latest Wordian; the Dulhuntyispora dulhuntyi (APP4.3) Zone is exceptionally short and lies within the Wuchiapingian, not the early Capitanian; and the top of the Dulhuntyispora parvithola (APP5) Zone lies at or near the Permo-Triassic boundary, not in the latest Wuchiapingian.

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 Gunnedah 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 Gunnedah Basin is an intracratonic, sedimentary basin in northern NSW. It forms the middle section of the greater Sydney-Gunnedah-Bowen Basin system and mainly consists of Permian and Triassic sedimentary rocks resting on Late Carboniferous to Early Permian volcanics. The Gunnedah Basin is overlain by the Surat Basin and the younger alluvial sediments associated with modern and ancient river systems. The Gunnedah Basin is not considered a single well-connected aquifer, rather a series of porous rock aquifers separated by several non-porous or poorly conductive layers. The Lachlan Fold Belt forms what is thought to be an effective basement although little information is known of its hydrogeological properties. All units of the Gunnedah Basin are of low permeability and significantly lower hydraulic conductivity than the overlying alluvial aquifers. Most of the groundwater resources in the area are extracted from either the overlying Surat Basin or younger alluvial aquifers. There is relatively little groundwater sourced from the aquifers of the Gunnedah Basin, except in areas where the overlying aquifers do not occur. The most viable groundwater source in the Gunnedah Basin are the more porous aquifers of the Triassic sequence.

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.

Discusses requirements of a stratigraphic unit definition and why geoscientists should write more of them, where to research background information, where to get advice, and what standards apply.