This web service provides access to satellite imagery products for the identification of potential groundwater dependent ecosystems (GDEs) in the South Nicholson - Georgina region.

Stratigraphic drill hole NDI Carrara 1 was drilled as a collaboration between Geoscience Australia (GA), the Northern Territory Geological Survey (NTGS) and the Mineral Exploration Cooperative Research Centre (MinEx CRC). It reached a total depth of 1751 m in late 2020 and is the first drill hole to intersect the undifferentiated Proterozoic rocks of the Carrara Sub-Basin. It intersected approximately 630 m of Cambrian Georgina Basin sedimentary rocks overlying the ~1100 m of Proterozoic carbonates, black shales and other siliciclastics of the Carrara Sub-Basin succession. The formational assignments of the Georgina Basin succession are preliminary and were assigned in the field. The units intersected comprise the Border Waterhole Formation (~531m to ~630m), which is overlain by the Currant Bush Limestone (~249m to ~531m), which in turn is overlain by the Camooweal Dolostone (0m to ~249m). Of these, only the lower 80% of the Currant Bush Limestone and the entire Border Waterhole Formation were cored. This report presents biostratigraphic results from macrofossil examination of NDI Carrara 1 core samples within the Georgina Basin section.

The Exploring for the Future Program facilitated the acquisition of major geoscience datasets in northern Australia, where rocks are mostly under cover and the basin evolution, mineral, energy and groundwater resource potential are, in places, poorly constrained. In an effort to support sustainable, regional economic development and build stronger communities in these frontier areas, integration of new and legacy data within a consistent platform could enhance the recognition of cross-disciplinary synergies in sub-surface resource investigations. Here we present a case study in the South-Nicholson Basin, located in a poorly exposed area between the prospective Mt Isa Province and the McArthur Basin. Both regions host major base metal deposits, contain units prospective for energy resources, and hold significant groundwater resources in the overlying Georgina Basin. In this study, we interpret a subset of new regional-scale data, which include ~1 900 km of deep seismic reflection data and 60 000 line kilometres of AusAEM1 airborne electromagnetic survey, supplemented with legacy information. This interpretation refines a semi-continental geological framework, as input to national coverage databases and informs decision-making for exploration and groundwater resource management. This study provides a 3D chronostratigraphic cover model down to the Paleoproterozoic basement. We mapped the depth to the base of intervals corresponding to geological eras, as well as deeper pre-Neoproterozoic superbasin boundaries to refine the cover model. The depth estimates, based on the compilation, interpretation and integration of geological and geophysical datasets, inform the basement architecture controls on evolution of the basin, with several key outcomes: 1) expanded mapped size of the South Nicholson Basin, potentially, increasing prospectivity for hydrocarbons and basin-hosted mineralisation, 2) improved stratigraphic unit correlations across the region, 3) identification of major crustal structures, some of which are associated with mineralisation and springs, and 4) improved basin architecture definition, supporting future investigation of groundwater resources.

NDI Carrara 1 is a deep stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-basin, a newly discovered Proterozoic depocentre in the South Nicholson region, based on interpretation from new seismic surveys (L210 in 2017 and L212 in 2019) acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1120 m of Proterozoic sedimentary rocks unconformably overlain by 630 m of Cambrian Georgina Basin carbonates. Continuous cores recovered from 283 m to a total depth of 1751 m. Geoscience Australia conducted an extensive post-drilling analytical program that generated over 30 datasets which the interested reader can find under the EFTF webpage (under the "Data and publications" drop down menu) at https://www.eftf.ga.gov.au/south-nicholson-national-drilling-initiative This record links to the Exploring for the Future 'borehole completion report' for NDI Carrara 1 and access to all on-site downhole geophysical datasets.

Following the publication of Geoscience Australia record 2014/09: Petroleum geology inventory of Australia's offshore frontier basins by Totterdell et. al, (2014), the onshore petroleum section embarked upon a similar project for onshore Australian basins. The purpose of this project is to provide a thorough basis for whole of basin information to advise the Australia Government and other stakeholders, such as the petroleum industry, regarding the exploration status and prospectivity of onshore Australian basins. Eight onshore Australian basins have been selected for this volume and these include: the McArthur, South Nicholson, Georgina, Amadeus, Warburton, Wiso, Galilee and Cooper basins. This record provides a comprehensive whole of basin inventory of the geology, petroleum systems, exploration status and data coverage for these eight onshore Australian basins. It draws on precompetitive work programs by Geoscience Australia as well as publicly available exploration results and geoscience literature. Furthermore, the record provides an assessment of issues and unanswered questions and recommends future work directions to meet these unknowns.

Small-angle neutron scattering (SANS) measurements were performed on 32 rock samples from the southern Georgina Basin, central Australia to assess nanopore anisotropy. Anisotropy can only be determined from oriented core material, hence the samples were cut perpendicular to bedding in cores selected from three wells that intersect the base of the hydrocarbon-bearing, organic-rich middle Cambrian Arthur Creek Formation; the latter is the source rock for both unconventional and conventional plays in the basin. The evolution of anisotropy of two-dimensional SANS intensity profiles with depth (for pore diameters ranging from 10 nm to 100 nm) was quantified and correlated with SANS intensity and total organic carbon (TOC) content. Our results confirm hydrocarbon generation at the base of the Arthur Creek Formation. The nanopore anisotropy in the basal Arthur Creek Formation at the well locations CKAD0001 (oil generation window) and MacIntyre 1 (late oil generation window) varies roughly according to normal compaction. When the Arthur Creek Formation is in the gas window, as sampled at Baldwin 1, there is a strong (negative) correlation between the average vertical-to-horizontal pore shape anisotropy and SANS intensity. The results indicate that unconventional gas production from organic-rich regions of over mature shale may be adversely affected by abnormal pore compaction.

<div>Groundwater dependent ecosystems (GDEs) rely on access to groundwater on a permanent or intermittent basis to meet some or all of their water requirements (Richardson et al., 2011). The <a href="https://explorer-aws.dea.ga.gov.au/products/ga_ls_tc_pc_cyear_3">Tasseled Cap percentile products</a> created by Digital Earth Australia (2023) were used to identify potential GDEs for the South Nicholson-Georgina basins study area. These percentile products provide statistical summaries (10th, 50th, 90th percentiles) of landscape brightness, greenness and wetness in imagery acquired between 1987 and present day. The 10th percentile greenness and wetness represent the lowest 10% of values for the time period evaluated, e.g. 10th percentile greenness represents the least green period. In arid regions, areas that are depicted as persistently green and/or wet at the 10th percentile have the greatest potential to be GDEs. For this reason, and due to accessibility of the data, the 10th percentile Tasseled Cap greenness (TCG) and Tasseled Cap wetness (TCW) products were used as the basis for the assessment of GDEs for the South Nicholson-Georgina region. The 50th percentile greenness was utilised to create the coefficient of variance (CV) dataset. This data release is an ESRI geodatabase, with layer files, including: - combined classified 10th percentile greenness and wetness dataset (useful to identify potential groundwater dependent vegetation/other GDEs and differentiate between vegetation types) - CV of 50th percentile greenness dataset (useful when used in conjunction with the combined product to help identify groundwater dependent vegetation) For more information and detail on these products, refer to associated <a href="https://dx.doi.org/10.26186/149377">report</a>. </div><div><br></div><div><strong>References</strong></div><div>Digital Earth Australia (2023).&nbsp;<em><a href="https://docs.dea.ga.gov.au/">Digital Earth Australia User Guide.</a></em></div><div>Richardson, S., E. Irvine, R. Froend, P. Boon, S. Barber, and B. Bonneville. 2011a.&nbsp;<em>Australian groundwater-dependent ecosystem toolbox part 1: Assessment framework.</em>&nbsp;Waterlines Report 69. Canberra, Australia: Waterlines.</div><div><br></div>

<div>This study investigates the feasibility of mapping potential groundwater dependent vegetation (GDV) at a regional scale using remote sensing data. Specifically, the Digital Earth Australia (DEA) Tasseled Cap Percentiles products, integrated with the coefficient of greenness and/or wetness, are applied in three case study regions in Australia to identify and characterise potential terrestrial and aquatic groundwater dependent ecosystems (GDE). The identified high potential GDE are consistent with existing GDE mapping, providing confidence in the methodology developed. The approach provides a consistent and rapid first-pass approach for identifying and assessing GDEs, especially in remote areas of Australia lacking detailed GDE and vegetation information.</div>

Small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) are used to directly detect the processes of hydrocarbon generation in the 10 nm to 10 μm size pores in carbonate and siliciclastic rocks which contain no land-plant material suitable for conventional maturity determination by vitrinite reflectance. The method takes advantage of the pore-size-specific variation of neutron scattering contrast between the solid rock matrix and pore-space content with depth, which is caused by thermal maturation of organic matter through the oil and gas generation windows. SANS and USANS measurements were performed on bedding plane-orientated core slices, extracted from a series of 10 to 12 depth intervals for three wells, CKAD0001, MacIntyre 1 and Baldwin 1 in the southern Georgina Basin, central Australia. The depth intervals, intersecting the organic-rich basal ‘hot’ shales of the middle Cambrian Arthur Creek Formation, were selected based on Rock-Eval pyrolysis data. SANS and USANS results indicate that oil generation has occurred in the past in nano-sized pores in rocks that are now at depths of around 538.4 m in CKAD0001 and 799.3 m in MacIntyre 1. Furthermore, in the CKAD0001 well, the oil-wet pores extend into the larger pore-size range (at least up to 10 μm) due to the efficient expulsion of oil. At around 880 m in Baldwin 1, the influence of pyrobitumen reverts pore space from gas wet to oil wet. These hydrocarbons have remained in situ since the Devonian when the Neoproterozoic to Paleozoic section was exhumed in the Alice Springs Orogeny and subsequently eroded, preserving only remnants of the once extensive basin sediments.

<div>This data package is a key output from the integrated, basin-scale hydrogeological assessment of South Nicholson-Georgina as part of Geoscience Australia’s National Groundwater Systems project in the Exploring for the Future program.&nbsp;This comprehensive desktop study has integrated numerous geoscience and hydrogeological datasets to develop a new whole-of-basin conceptualisation of groundwater flow systems and recharge and discharge processes within the regional unconfined aquifers of the Georgina Basin.</div><div><br></div><div>This data release includes an ESRI geodatabase and ESRI shapefiles with associated layer files:</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Georgina Basin watertable trend surface</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Georgina Basin reduced standing water level (RSWL) contours</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Regional scale groundwater divides</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Groundwater flow paths</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Bores with aquifer attribution and water level information where available</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Hydrochemistry data for bores and springs, and aquifer attribution (where available)</div><div>-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Basin boundary extents</div><div><br></div><div>For more information and detail on these products, refer to associated report, Dixon-Jain et al. (2024).</div><div><br></div><div>Dixon-Jain, P., Bishop, C., Lester, J., Orlov, C., McPherson, A., Pho, G., Flower, C., Kilgour, P., Lawson, S., Vizy, J., Lewis, S. 2024. Hydrogeology and groundwater systems of the South Nicholson and Georgina basins, Northern Territory and Queensland. Record 2024/37. Geoscience Australia, Canberra. https://dx.doi.org/10.26186/149730</div>