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.

Geoscience Australia, in collaboration with state government agencies, has been collecting magnetotelluric (MT) data as part of the Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) for several years. This program aims to map the electrical resistivity of the rock layers, at depths from ten kilometres to hundreds of kilometres, across the entire continent. AusLAMP sites are each about 55 km apart from each other. Locations are chosen in consultation with landholders and other stakeholders to minimise impacts and avoid disturbance.MT data is collected using sensors that record naturally occurring variations of the Earth’s magnetic and electric fields. The equipment does not produce or transmit and signals. After four to six weeks the equipment is retrieved and the site restored to its original condition.

The focus of this project is to use data from space gravity missions to track changes in total water storage in northern Australia and to investigate the viability of this approach for monitoring Australia’s water resources. The specific objective of the project is to “develop time series of changes in total water storage across northern Australia to provide insights into changes in water resources.” Data from the Gravity Recovery and Climate Experiment (GRACE) mission was analysed for the period January 2003 to August 2016 and monthly estimates of changes (relative to a mean gravity field value in 2008) were developed. The analysis was done using the ANU GRACE software, which has been developed specifically to enable estimates to be tailored to the pattern and shape of Australian drainage basins. Estimates in irregularly shaped regions of approximately 90,000 km2 have been provided, along with visualisation tools to enable time series of total water storage changes to be made. This package contains: 1) Final report provided to Geoscience Australia by ANU 2) GRACE total water storage change dataset The dataset includes the original data provided by ANU as well as images/video derived from the data to help with visualisation. a) ANU_iter2_australia.nc: the total water storage changes estimate from GRACE satellite gravity mission measurements b) BOM-final.nc, GLDAS-CLSM-final.nc, GLDAS-NOAH-final-nc: the canopy, snow and soil water storage changes estimate from hydrological models c) mascons_stage5_V004_australia: the mascon file describing the geometry of the mascon grid over australia d) plot_ewh_time_series.py, plot_soil_moisture_time_series.py and plot_gw_time_series.py: python scripts allowing to plot time series of total water storage, canopy, snow or soil water storage and groundwater storage for any latitude, longitude in Australia e) map_mascons_australia.py and map_ewh_australia.py: python scripts to create maps of the mascon geometry and ewh anomaly f) monthly images of the total water storage and videos depicting changes for each month over the years (2003-2016) and video with all months stitched together. Geoscience Australia commissioned the work as part of the 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.

New multidisciplinary data collected as part of the Exploring for the Future (EFTF) Program has changed our understanding of the basement geology of the East Tennant region in the Northern Territory, and its potential to host mineralisation. To ensure this understanding is accurately reflected in geological maps, we undertake a multidisciplinary interpretation of the basement geology in East Tennant. For the purposes of this product, basement comprises polydeformed and variably metamorphosed rocks of the pre-1800 Ma Warramunga Province, which are exposed in outcrop around Tennant Creek, to the west. In the East Tennant region, these rocks are entirely covered by younger flat-lying strata of the Georgina Basin, and locally covered by the Kalkarindji Suite, and South Nicholson Basin (Ahmad 2000). The data from this solid geology map are designed to be included in mineral potential models and future updates to Geoscience Australia’s chronostratigraphic solid geology maps. This interpretation comprises a Geographic Information System (GIS) dataset containing basement geology polygons, faults and contacts. Geological units are consistent with the Australian Stratigraphic Units Database and faults utilise existing conventions followed by Geoscience Australia’s chronostratigraphic solid geology products (Stewart et al. 2020). To aid in understanding the data, we have added a three-stage fault hierarchy. Basement geology was interpreted at 1:100000 scale (but is intended for display at 1:250000 scale) using geophysical imagery, namely total magnetic intensity and vertical derivatives of these data, and gravity. The interpretation makes use of numerous new datasets collected as part of the EFTF program. These include a new 2-km spaced gravity grid over most of East Tennant, drill-core lithology from new boreholes drilled as part of the MinEx CRC National Drilling Initiative, airborne electromagnetic data collected under the AusAEM program, new active seismic data, and geochronology from legacy boreholes. These data are available to view and download from the Geoscience Australia portal (https://portal.ga.gov.au). We interpret that basement in the East Tennant region does represent the eastern continuation of the Warramunga Province. There is no obvious geophysical or geological boundary between Tennant Creek and East Tennant. However, the East Tennant region mostly lacks stratigraphy equivalent to the Ooradidgee Group, which overlies and postdates mineralisation in turbiditic rocks of the Warramunga Formation at Tennant Creek. Instead, East Tennant is underlain by a widespread succession of clastic metapelitic rocks that bear many lithological and geochronological similarities to the Warramunga Formation (Cross et al. 2020). Other important outcomes of this work include the documentation of significant regional faults and shear zones and abundant intrusive rocks at East Tennant. Geophysical and geochronological data suggest that this deformation and magmatism is the eastern continuation of ~1850 Ma tectonism preserved at Tennant Creek (e.g. Cross et al. 2020). NOTE: Specialised (GIS) software is required to view this data. References: Ahmad M, 2000. Geological map of the Northern Territory. 1:2 500 000 scale. Northern Territory Geological Survey, Darwin. Cross AJ, Clark AD, Schofield A and Kositcin N, 2020. New SHRIMP U-Pb zircon and monazite geochronology of the East Tennant region: a possible undercover extension of the Warramunga Province, Tennant Creek. In: Czarnota K, Roach I, Abbott S, Haynes M, Kositcin N, Ray A and Slatter E (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4. Stewart AJ, Liu SF, Bonnardot M-A, Highet LM, Woods M, Brown C, Czarnota K and Connors K, 2020. Seamless chronostratigraphic solid geology of the North Australian Craton. In: Czarnota K, Roach I, Abbott S, Haynes M, Kositcin N, Ray A and Slatter E (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

<p>The South West McArthur, Barkly Gravity Survey P201901 is a gravity survey jointly funded under Geoscience Australia’s (GA) Exploring for the Future program and the Northern Territory Geological Survey's (NTGS) Resourcing the Territory 2018-2022 Initiative. Atlas Geophysics was commissioned by GA to conduct the survey, supporting both GA's and NTGS's programs. The survey supports GA's Exploring for the Future program, and NTGS's unlocking the resource potential of the Barkly Tablelands. <p>The survey infills existing 4km gravity coverage to 2km coverage. This is the second part of a larger gravity survey, the first being the East Tennant Gravity Survey P201901, NT, 2019 (eCat number 132968). Together the two surveys can be called the Tennant Creek Mount Isa (TISA) Gravity Surveys, P201901. <p>The data package consist of 3,303 gravity stations as a point located dataset and grids of the newly acquired gravity data

This report presents key results from hydrogeological investigations in the Tennant Creek region, 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 EFTF Southern Stuart Corridor (SSC) Project area is located in the Northern Territory and extends in a north–south corridor from Tennant Creek to Alice Springs, encompassing four water control districts and a number of remote communities. Water allocation planning and agricultural expansion in the SSC is limited by a paucity of data and information regarding the volume and extent of groundwater resources and groundwater systems more generally. Geoscience Australia, in partnership with the Northern Territory Department of Environment and Natural Resources and Power and Water Corporation, undertook an extensive program of hydrogeological investigations in the SSC Project area between 2017 and 2019. Data acquisition included; helicopter airborne electromagnetic (AEM) and magnetic data; water bore drilling; ground-based and downhole geophysical data for mapping water content and defining geological formations; hydrochemistry for characterising groundwater systems; and landscape assessment to identify potential managed aquifer recharge (MAR) targets. This report focuses on the Tennant Creek region—part of the Barkly region of the Northern Territory. Investigations in this region utilised existing geological and geophysical data and information, which were applied in the interpretation and integration of AEM and ground-based geophysical data, as well as existing and newly acquired groundwater hydrochemical and isotope data. The AEM and borehole lithological data reveal the highly weathered (decomposed) nature of the geology, which is reflected in the hydrochemistry. These data offer revised parameters, such as lower bulk electrical conductivity values and increased potential aquifer volumes, for improved modelling of local groundwater systems. In many instances the groundwater is shown to be young and of relatively good quality (salinity generally <1000 mg/L total dissolved solids), with evidence that parts of the system are rapidly recharged by large rainfall events. The exception to this is in the Wiso Basin to the west of Tennant Creek. Here lower quality groundwater occurs extensively in the upper 100 m below ground level, but this may sit above potentially potable groundwater and that possibility should be investigated further. Faults are demonstrated to have significantly influenced the occurrence and distribution of weathered rocks and of groundwater, with implications for groundwater storage and movement. Previously unrecognised faults in the existing borefield areas should be investigated for their potential role in compartmentalising groundwater. Additionally a previously unrecognised sub-basin proximal to Tennant Creek may have potential as a groundwater resource or a target for MAR. This study has improved understanding of the quantity and character of existing groundwater resources in the region and identified a managed aquifer recharge target and potential new groundwater resources. The outcomes of the study support informed water management decisions and improved water security for communities; providing a basis for future economic investment and protection of environmental and cultural values in the Tennant Creek and broader Barkly region. Data and information related to the project are summarised in the conclusions of this report and are accessible via the EFTF portal (https://portal.ga.gov.au/).

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.

Geoscience Australia and its predecessors have analysed hydrochemistry of water sampled from boreholes (both pore water and groundwater), surface features, and rainwater. Sampling was undertaken during drilling or monitoring projects, and this dataset represents a significant subset of stored analyses. Water chemistry including isotopic data is essential to better understand groundwater origins, ages and dynamics, processes such as recharge and inter-aquifer connectivity and for informing conceptual and numerical groundwater models. This GA dataset underpins a nationally consistent data delivery tool and web-based mapping to visualise, analyse and download groundwater chemistry and environmental isotope data. This dataset is a spatially-enabled groundwater hydrochemistry database based on hydrochemistry data from projects completed in Geoscience Australia. The database includes information on physical-chemical parameters (EC, pH, redox potential, dissolved oxygen), major and minor ions, trace elements, nutrients, pesticides, isotopes and organic chemicals. Basic calculations for piper plots colours are derived from Peeters, 2013 - A Background Color Scheme for Piper Plots to Spatially Visualize Hydrochemical Patterns - Groundwater, Volume 52(1) <https://doi.org/10.1111/gwat.12118>. Upon loading the data to the database, all hydrochemistry data are assessed for reliability using Quality Assurance/Quality Control procedures and all datasets were standardised. This data is made accessible with open geospatial consortium (OGC) web services and is discoverable via the Geoscience Australia Portal (<a href="https://portal.ga.gov.au/">https://portal.ga.gov.au/</a>). This dataset is published with the permission of the CEO, Geoscience Australia.

Salinity of groundwater directly affects its suitability for different uses, including human consumption, stock water, agricultural use, and mineral or energy extraction. Traditionally, direct measurements of groundwater salinity at monitoring bores that intersect an aquifer have been used to map the spatial distribution of groundwater salinity. However, drilling is a logistically and economically challenging task, and we are usually left with a sparse set of measurements from which to infer groundwater salinity over large spatial extents. Airborne electromagnetic (AEM) sounding provides a solution to this problem. This is because AEM can be flown rapidly and cost-effectively over large swathes of land, and high subsurface bulk conductivities inferred from the AEM are well correlated with groundwater salinity in porous aquifers. We present here a methodology and case study from the Keep River Plains in the Northern Territory that provides information for land and watershed managers about the confidence with which salinity can be mapped over large areas using AEM. Extensive pore fluid sampling of the saturated zone, which lies beneath the watertable, enables this workflow to be used effectively. The results provided by our method can feed into decision making while accounting for uncertainty, enabling remote communities to manage their land and water resources effectively. <b>Citation:</b> Symington, N.,Ray, A., Harris-Pascal, C., Tan, K.P., Ley-Cooper, A.Y., and Brodie, R.C., 2020. Groundwater salinity estimation using borehole and AEM data: a framework for uncertainty analysis. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

SHRIMP U-Pb zircon and monazite geochronology of magmatic, metamorphic and sedimentary rocks sampled from an undercover region informally referred to as ‘East Tennant’, located approximately 200 km east of Tennant Creek, has redefined our knowledge of the geology of this region. These results establish strong temporal links with rocks in the Au-Cu-Bi mineralised Tennant Creek region (Warramunga Province) and the Paleoproterozoic Murphy Province, approximately 270 km to the northeast. Detrital zircon U-Pb analyses of two metasedimentary samples show maximum depositional ages of ca. 1875 Ma and detrital zircon age spectra similar to Warramunga Formation metasedimentary rocks in the Warramunga Province. Additionally, three extrusive rocks and an intermediate intrusive rock have magmatic crystallisation ages of 1858–1849 Ma, synchronous with magmatism in the Warramunga Province associated with the 1860–1845 Ma Tennant Event. Monazite U-Pb analyses of two samples of metapelites from the East Tennant region and Murphy Province record metamorphism at ca. 1845 Ma, which is also synchronous with magmatism associated with the Tennant Event. These new results suggest that the undercover East Tennant region could represent an extension of the Warramunga Province and therefore be prospective for Au-Cu-Bi mineralisation. <b>Citation:</b> Cross, A.J., Clark, A.D., Schofield, A. and Kositcin, N., 2020. New SHRIMP U-Pb zircon and monazite geochronology of the East Tennant region: a possible undercover extension of the Warramunga Province, Tennant Creek. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.