The Source Rock and Fluids Atlas delivery and publication services provide up-to-date information on petroleum (organic) geochemical and geological data from Geoscience Australia's Organic Geochemistry Database (ORGCHEM). The sample data provides the spatial distribution of petroleum source rocks and their derived fluids (natural gas and crude oil) from boreholes and field sites in onshore and offshore Australian basins. The services provide characterisation of source rocks through the visualisation of Pyrolysis, Organic Petrology (Maceral Groups, Maceral Reflectance) and Organoclast Maturity data. The services also provide molecular and isotopic characterisation of source rocks and petroleum through the visualisation of Bulk, Whole Oil GC, Gas, Compound-Specific Isotopic Analyses (CSIA) and Gas Chromatography-Mass Spectrometry (GCMS) data tables. Interpretation of these data enables the characterisation of petroleum source rocks and identification of their derived petroleum fluids that comprise two key elements of petroleum systems analysis. The composition of petroleum determines whether or not it can be an economic commodity and if other processes (e.g. CO2 removal and sequestration; cryogenic liquefaction of LNG) are required for development.

This report presents groundwater levels results from the Howard East groundwater project in the Northern Territory (NT), conducted as part of Exploring for the Future (EFTF), an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. The Howard East groundwater project is a collaborative study between Geoscience Australia and he Northern Territory Government’s Department of Environment and Natural Resources (DENR). It focuses on groundwater resources in the Howard East area, NT. This report describes a data release of groundwater levels and salinity information based on measurements collected in monitoring bores during the EFTF project. The full report includes: • A full description of how water levels in metres relative to Australian Height Datum (m AHD; where zero m AHD is an approximation of mean sea level) were calculated from manual dips and electronic data loggers for this project. • A series of tables in Appendix A containing sufficient information for each bore and datalogger file to reproduce the water levels reported in Appendix B and Appendix C. • A series of hydrographs in Appendix B showing how water levels (in m AHD) interpreted from manual dips and datalogger files varied during the EFTF project. • A series of electronic files in Appendix C that include - Data files from dataloggers in CSV file format that can be used with the information contained in this data release to regenerate the water levels shown on hydrographs in Appendix A. - Data files in CSV file format reporting the final water levels used to generate the hydrographs in Appendix B.

The Ordovician to Cretaceous Canning Basin of Western Australia is an underexplored prospective onshore petroleum basin with proven petroleum systems currently producing on a small-scale. The Canning Basin has recently become a site of interest for unconventional hydrocarbon exploration, with several formations within deeper basin depocentres being investigated for resources and estimates that suggest it may have the largest shale gas potential in Australia. Modern petroleum resource evaluation generally depends on an understanding of both local and regional stresses, which are a primary control over the formation and propagation of induced fractures. Presently, there are significant gaps in our understanding of these factors within the Canning Basin. This study characterises the regional stress regime of the onshore Canning Basin and presents detailed models of present-day stress within the subsurface. These allow for the identification of significant stress heterogeneities and natural barriers to fracture propagation. Wireline data interpretation reveals a variable present-day state of stress in the Canning Basin. An approximately NE-SW regional present-day maximum horizontal stress orientation is interpreted from observed wellbore failure in image logs, in broad agreement with both the Australian Stress Map and previously published earthquake focal mechanism data. One-dimensional mechanical earth models constructed for intervals from 15 Canning Basin petroleum wells highlight the relationship between lithology and stress. This study describes significant changes in stress within and between lithological units due to the existence of discrete mechanical units, forming numerous inter- and intra- formational stress boundaries likely to act as natural barriers to fracture propagation, particularly within units currently targeted for their unconventional resource potential. Broadly, a strike-slip faulting stress regime is interpreted through the basin, however, when analysed in detail there are three distinct stress zones identified.: 1) a transitional reverse- to strike-slip faulting stress regime in the top ~1 km of the basin, 2) a strike-slip faulting stress regime from ~1 km to ~3.0 km depth, and 3) a transitional strike-slip to normal faulting regime at depths greater than ~3.0 km. This study is a component of the Australian Government’s Exploring for the Future (EFTF) initiative, which is focused on gathering new data and information about the resource potential concealed beneath the surface across northern Australia. Appeared online in the Australian Journal of Earth Sciences 17 Feb 2021

The Exploring for the Future program is an initiative by the Australian Government dedicated to boosting investment in resource exploration in Australia. As part of the Exploring for the Future program, this study aims to improve our understanding of the petroleum resource potential of northern Australia. This data release presents new field emission scanning electron microscopy (FE-SEM) of broad ion beam- polished samples (BIB-SEM) to visualise mineral and organic matter (OM) porosity on 15 Proterozoic aged shales. Samples were selected from the Velkerri and Barney Creek formations in the McArthur Basin and the Mullera Formation, Riversleigh Siltstone, Lawn Hill and Termite Range formations in the South Nicholson region. Qualitative maceral analysis of the 15 samples are described in addition to bitumen reflectance measurements. These samples were analysed at the Montanuniversität Leoben, Austria in June 2020. The results of this study can be used to improve our understanding of porosity, microstructures, seal capacity and hydrocarbon prospectivity of Proterozoic aged sedimentary basins in northern Australia.

The Source Rock and Fluids Atlas delivery and publication services provide up-to-date information on petroleum (organic) geochemical and geological data from Geoscience Australia's Organic Geochemistry Database (ORGCHEM). The sample data provides the spatial distribution of petroleum source rocks and their derived fluids (natural gas and crude oil) from boreholes and field sites in onshore and offshore Australian basins. The services provide characterisation of source rocks through the visualisation of Pyrolysis, Organic Petrology (Maceral Groups, Maceral Reflectance) and Organoclast Maturity data. The services also provide molecular and isotopic characterisation of source rocks and petroleum through the visualisation of Bulk, Whole Oil GC, Gas, Compound-Specific Isotopic Analyses (CSIA) and Gas Chromatography-Mass Spectrometry (GCMS) data tables. Interpretation of these data enables the characterisation of petroleum source rocks and identification of their derived petroleum fluids that comprise two key elements of petroleum systems analysis. The composition of petroleum determines whether or not it can be an economic commodity and if other processes (e.g. CO2 removal and sequestration; cryogenic liquefaction of LNG) are required for development.

This report presents key results from the Ti Tree Basin project completed as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. The Ti Tree Basin is one of four Northern Territory water management areas in the Southern Stuart Corridor (SSC) area, part of Geoscience Australia’s Exploring for the Future project. The Ti Tree Basin is approximately 150–200 kilometres north of Alice Springs. The intracratonic basin is infilled Cenozoic alluvial and lacustrine sediments. Since the 1960s the basin has been the focus of many government investigations and policies into its groundwater potential. Most have concentrated on the relatively shallow Cenozoic aquifers less than 100 metres below surface. Wischusen et al. (2012) identified the potential of the deeper aquifers (at depths of greater than 100 m) to expand the potential water resources of the Ti Tree Basin. This report uses three sets of AEM data, two acquired by Geoscience Australia and one from historic mineral exploration, to map the depth to basement in the Ti Tree Basin. We confirm the prediction of Wischusen et al. (2012) that there is significant potential for a much thicker Cenozoic succession in the Basin and show that up to 500 m of sediments are present in fault bounded structures. We demonstrate that these sediments occur in two successions, one of probably Eocene age within narrow, fault-bounded troughs and the other of probable Miocene to Pliocene age occurring across a wider area. The two successions are separated by a low angle unconformity. We interpret the lower succession as forming during strike-slip opening of the basin, and the upper succession as being deposited by passive basin infill. The faults forming the deep basin show are mostly congruent with basement structures previously interpreted from aeromagnetic data. Most of the lower succession has not been fully penetrated by earlier drilling. The interpreted AEM data shows that the deep Ti Tree Basin may contain extensive sandy aquifer units whose potential are completely unexplored. We recommend further investigations, including further stratigraphic drilling, mapping of the uniformity surface, and installation of monitoring bores, to more fully explore the potential of the deep Ti Tree Basin.

This report presents key results from the Ti Tree Basin project completed as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. Hydrogeological data acquisition and interpretation in the Ti Tree Basin, Northern Territory, was undertaken by Geoscience Australia as part of the EFTF Program. Located ~150 km north of Alice Springs, the Cenozoic basin hosts regionally significant groundwater resources, relied upon by communities, irrigators and pastoralists. Although the basin has been extensively studied over several decades, critical information gaps still remain, particularly for the deep groundwater system (>80 m depth). Work combining new geophysical and hydrochemical data with pre-existing datasets has revealed a more complex basin hydrogeology. Mapping based on airborne electromagnetics (AEM) has identified complex structural controls on the distribution of the deep basin sequence, with consequences for aquifer compartmentalisation, regional groundwater flow and aquifer connectivity. The mapping also shows where the basin sediments are much thicker than previously drilled. The hydrochemical assessment highlighted the complexity in groundwater recharge mechanisms, showing that the rainfall threshold for effective recharge and the role of evaporation are not consistent across the floodout zones in the basin. The EFTF products provide guidance for future hydrogeological investigations. In particular, there is evidence from historic drilling for potentially useful groundwater resources in the underexplored deep basin sequence. The EFTF program has expanded the knowledge base and datasets for the Ti Tree Basin. Collectively, these are valuable assets not just for basin groundwater management but also for the broader understanding of groundwater resources and processes in central Australia.

This report presents key results of the Ti Tree Basin study completed as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. As part of EFTF, Geoscience Australia undertook an assessment of available and new hydrochemical data collected in the Ti Tree Basin, Northern Territory. The basin is one of the four water control districts within the Southern Stuart Corridor Project area. Communities, irrigation farms and pastoral stations in the basin rely on groundwater, and extensive groundwater sampling and hydrochemical investigations have been undertaken over the past 50 years. An opportunity was recognised to collate and interpret the existing data, supplemented by new EFTF data, not only to add value to the understanding of groundwater processes in the basin itself but also to provide a useful knowledge base for other groundwater resources in the region that are poorly understood. This study largely relied on the available groundwater analysis data from the Northern Territory Department of Environment and Natural Resources database, supplemented by publicly available analyses from other sampling campaigns, including the EFTF, totaling 1913 groundwater samples across the district. The key findings of the study are: • The hydrochemistry data, particularly on salinity (total dissolved solids (TDS)), ion ratios (e.g. HCO3/Cl, Cl/(Cl+HCO3), Cl/(Cl+HCO3+SO4), Na/Cl) and radiocarbon (14C) could be used to map the three major recharge areas for the basin—the floodout of the Woodforde River to the west, the floodout of Allungra Creek in the basin centre, and the eastern basin margin. This is consistent with the current accepted interpretation that recharge is dominated by episodic run-on and infiltration in drainage floodout areas, driven by intense rainfall events that generate runoff in upland basement headwaters and ephemeral flows in basin creeks. There are no hydrochemical indicators of recharge in the vicinity of the channelised reaches of the basin creeks (i.e. both Woodforde River and Allungra Creek), located upstream of the floodouts. • From a groundwater resource perspective, the Allungra Creek floodout has broadly the best combination of low-salinity groundwater (median TDS = 740 mg/L) and bore yield statistics (median = 10 L/s). The Woodforde River floodout also has areas with high-yielding bores (>10 L/s) of fresh groundwater (<1000 mg/L), with the borehole distribution suggesting that the fresh groundwater resource is significantly more extensive to the west of the river than that previously mapped. The eastern basin margin generally has low-salinity groundwater (median TDS = 775 mg/L) but lower bore yields (median = 4.4 L/s). • There are differences in the recharge characteristics of the three floodout areas, due to differences in drainage catchments and floodout hydrogeology. The Woodforde River floodout has the most depleted stable isotopes, interpreted to be due to a higher rainfall/runoff threshold for recharge (>150 mm/month). It also has the largest isotopic range and the best δ18O-δ2H linear regression, suggesting the most influence of evaporation, such as a longer period of surface water ponding. In comparison, the stable isotope signature for Allungra Creek groundwaters suggests a lower rainfall/runoff threshold for recharge (>100 mm/month) and low evaporative influence, hence relatively rapid infiltration. This is also inferred to be the case for the low-salinity eastern basin margin groundwaters. For both Woodforde River and Allungra Creek, modern recharge is indicated by groundwaters with high radiocarbon activity (14C percent modern carbon (pMC) >70). For the eastern basin margin, radiocarbon activity is low to moderate (14C pMC 20–50). This is interpreted to reflect a longer travel time in the unsaturated zone. • In the floodout areas, the dominant hydrogeochemical process relating to the fresh groundwater is water–rock interactions. Groundwater tends to be the least evolved Ca(Mg)-HCO3 or transitional Na(K)-HCO3 water type, according to Chadha plots. Zones of prevalence of carbonate-gypsum dissolution or Na-silicate weathering could be mapped using indicators such as cation chloride ratio. Ion exchange is also a likely process in these fresh groundwaters, as inferred from chloro-alkaline indices. • Groundwater salinity is higher away from the floodout areas. This increased salinity is due to evapotranspirative concentration in addition to water–rock interactions, as inferred from ion ratios, including Cl/Br. Stable isotopes indicate that transpiration of groundwater by vegetation accessing the watertable, rather than direct evaporation, is the dominant process in these areas. This process is particularly evident in the Wilora Palaeochannel, the northern extension of the basin, which generally has the highest groundwater salinities (median TDS = 1575 mg/L), the lowest bore yields (median = 1.9 L/s) and the greatest prevalence of shallow watertables (<15 m). With higher salinities, groundwaters tend to be the evolved Ca(Mg)-Cl(SO4) and Na(K)-Cl(SO4) water types and potentially influenced by reverse ion exchange processes. • Mountain-front recharge has previously been proposed as an additional recharge mechanism, notably near the southern basin margin. Although sampling is limited in this area, hydrochemical indicators such as low HCO3/Cl, high Na/Cl and evolved Na(K)-Cl(SO4) water type suggests that active recharge is not significant. The watertable is deep along the southern basin margin (>50 m), so groundwater chemistry can be strongly influenced by processes during downward infiltration through a thick unsaturated zone. • Limited sampling of deeper bores (>80 m), potentially in the Hale Formation, generally have the characteristics of being more saline and lower yielding compared to bores in the shallow groundwater resource (particularly from 40 m to 80 m). However, there are deep bores with good yields of fresh groundwater; of 57 bores in the basin with interval depths exceeding 80 m, eight (14%) have the combination of yield >5 L/s and salinity <1000 mg/L. The deeper groundwaters are typically Ca(Mg)-Cl(SO4) and Na(K)-Cl(SO4) water types, with the latter, more evolved, water type dominating at depths >120 m. There are very few stable isotope analyses for the deeper groundwaters, but these are within the isotopic range for the shallow groundwaters in the same area, suggesting similarity in recharge processes and a degree of aquifer connectivity. Likewise, there are very few radiocarbon analyses for deeper groundwaters (depth >60 m), but these consistently show low 14C activity (pMC <40). The higher salinities, evolved water types and low 14C activity reflect longer residence times in the deeper groundwater system. The study highlighted that floodout recharge, involving episodic flow of basin creeks from headwater catchments, is the most dominant mechanism, rather than direct infiltration from large rainfall events. The study also identified that recharge characteristics, particularly the rainfall threshold for effective recharge and the role of evaporation, are not consistent across the floodout zones in the basin. This likely reflects differences in upland catchment size and geology, as well as floodout landform and hydrogeology. The study also highlighted the importance of groundwater-dependent vegetation in the basin, with dominance of transpiration of groundwater rather than direct evaporation. The groundwater hydrochemistry datasets and interpretation maps can support informed water management decisions within the basin. For example, improved understanding of the spatial and temporal distribution of recharge is not only needed for defining groundwater extraction limits but also used in strategies such as managed aquifer recharge. The EFTF work adds to the knowledge base and datasets that have developed over decades for the Ti Tree Basin, which are also valuable assets for broader understanding of groundwater resources in central Australia.

The hyperspectral HyLoggerTM instrument for collecting high resolution spectra data of drill core and drilling chips is a widely used and powerful in mineral and energy exploration, including sediment hosted mineralisation and hydrocarbons. It enables mapping of hydrothermal, diagenetic, and weathering assemblages, clarification of stratigraphy, and determination of primary mineralogy. This report presents key results of hyperspectral data from the HyLogger-3TM instrument collected from drilling in the Southern Stuart Corridor (SSC) project area in the Northern Territory conducted as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. The results show that HyLogger plots are in most cases in the most effective means of identification of stratigraphic contacts. HyLogger plots are also especially effective and determining the depth and mineralogy of weathering and distinguishing provenance in shallow transported material such as palaeovalley fill and alluvium. Geological observations are however still crucial, especially in determining texture, which cannot be determined by the HyLogger scans or from photographs of chips and core, and in cases where contamination obscures or confuses the spectral signals. Weathering in the SSC can be determined by the appearance of dickite and poorly crystalline kaolinite. This allows a better determination of base of weathering than visual means: generally based of the presence of oxidised iron phases such as goethite and haematite (which are not definitive where the rocks already contained these prior to weathering), or where oxidised iron deposition has not occurred. This aids in depth of weathering mapping from regional AEM data. The ability of the HyLogger to discriminate between swelling (montmorillonite) and non-swelling (kaolinite, dickite) clays is potentially significant in the prediction of aquifer properties and the validation of borehole MR methods. The detection of zones of potential dolomitisation and dedolomisation through mineralogy (presence of dolomite and possible secondary calcite and magnesite, respectively) in carbonate units has the potential to similarly predict properties in carbonate units, through the potential increase in porosity/permeability of the first and decreased porosity/permeability of the second.

This report presents key results of groundwater barometric response function development and interpretation from the Upper Burdekin Groundwater Project in North Queensland, conducted as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. The Upper Burdekin Groundwater Project is a collaborative study between Geoscience Australia and the Queensland Government. It focuses on basalt groundwater resources in two geographically separate areas: the Nulla Basalt Province (NBP) in the south and the McBride Basalt Province (MBP) in the north. The NBP and MBP basalt aquifers are heterogeneous, fractured, vesicular systems. This report assesses how water levels in monitoring bores in the NBP and MBP respond to barometric pressure changes to evaluate the degree of formation confinement. The main process used to evaluate water level response to barometric pressure in this study is based on barometric efficiency (BE). The BE of a formation is calculated by dividing the change in monitoring bore water level by the causative barometric pressure change. Both parameters are expressed in the same units, so BE will typically be some fraction between zero and one. BE is not necessarily constant over time; the way BE changes following a theoretical step change in barometric pressure can be described using a barometric response function (BRF). BRFs were calculated in the time domain and plotted as BE against time lag for interpretation. The BRF shape was used to assess the degree of formation confinement. Although there is some uncertainty due to monitoring bore construction issues (including long effective screens) and potentially air or gas trapped in the saturated zone, all BRFs in the current project are interpreted to indicate unconfined conditions. This finding is supported by the identification of recharge at many monitoring bores through hydrograph analysis in other EFTF project components. We conclude that formations are likely to be unconfined at many project monitoring bores assessed in this study.