We collected 38 groundwater and two surface water samples in the semi-arid Lake Woods region of the Northern Territory to better understand the hydrogeochemistry of this system, which straddles the Wiso, Tennant Creek and Georgina geological regions. Lake Woods is presently a losing waterbody feeding the underlying groundwater system. The main aquifers comprise mainly carbonate (limestone and dolostone), siliciclastic (sandstone and siltstone) and evaporitic units. The water composition was determined in terms of bulk properties (pH, electrical conductivity, temperature, dissolved oxygen, redox potential), 40 major, minor and trace elements as well as six isotopes (δ18Owater, δ2Hwater, δ13CDIC, δ34SSO4=, δ18OSO4=, 87Sr/86Sr). The groundwater is recharged through infiltration in the catchment from monsoonal rainfall (annual average rainfall ~600 mm) and runoff. It evolves geochemically mainly through evapotranspiration and water–mineral interaction (dissolution of carbonates, silicates, and to a lesser extent sulfates). The two surface waters (one from the main creek feeding the lake, the other from the lake itself) are extraordinarily enriched in 18O and 2H isotopes (δ18O of +10.9 and +16.4 ‰ VSMOW, and δ2H of +41 and +93 ‰ VSMOW, respectively), which is interpreted to reflect evaporation during the dry season (annual average evaporation ~3000 mm) under low humidity conditions (annual average relative humidity ~40 %). This interpretation is supported by modelling results. The potassium (K) relative enrichment (K/Cl mass ratio over 50 times that of sea water) is similar to that observed in salt-lake systems worldwide that are prospective for potash resources. Potassium enrichment is believed to derive partly from dust during atmospheric transport/deposition, but mostly from weathering of K-silicates in the aquifer materials (and possibly underlying formations). Further studies of Australian salt-lake systems are required to reach evidence-based conclusions on their mineral potential for potash, lithium, boron and other low-temperature mineral system commodities such as uranium. <b>Citation:</b> P. de Caritat, E. N. Bastrakov, S. Jaireth, P. M. English, J. D. A. Clarke, T. P. Mernagh, A. S. Wygralak, H. E. Dulfer & J. Trafford (2019) Groundwater geochemistry, hydrogeology and potash mineral potential of the Lake Woods region, Northern Territory, Australia, <i>Australian Journal of Earth Sciences</i>, 66:3, 411-430, DOI: 10.1080/08120099.2018.1543208

Mineral deposits are the products of lithospheric-scale processes. Imaging the structure and composition of the lithosphere is therefore essential to better understand these systems, and to efficiently target mineral exploration. Seismic techniques have unique sensitivity to velocity variations in the lithosphere and mantle, and are therefore the primary means available for imaging these structures. Here, we present the first stage of Geoscience Australia's passive seismic imaging project (AusArray), developed in the Exploring for the Future program. This includes generation of compressional (P) and shear (S) body-wave tomographic imaging models. Our results, on a continental scale, are broadly consistent with a priori expectations for regional lithospheric structure and the results of previously published studies. However, we also demonstrate the ability to resolve detailed features of the Australian lithospheric mantle underneath the dense seismic deployments of AusArray. Contrasting P- and S-wave velocity trends within the Tennant Creek – Mount Isa region suggest that the lithospheric root may have undergone melt-related alteration. This complements other studies, which point towards high prospectivity for iron oxide–copper–gold mineralisation in the region. <b>Citation: </b>Haynes, M.W., Gorbatov, A., Hejrani, B., Hassan, R., Zhao, J., Zhang, F. and Reading, A.M., 2020. AusArray: imaging the lithospheric mantle using body-wave tomography. 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.

To meet the rising global demand for base metals – driven primarily by the transition to cleaner-energy sources – declining rates of discovery of new deposits need to be countered by advances in exploration undercover. Here, we report that 85% of the world’s sediment-hosted base metals, including all giant deposits (>10 Mt of metal), occur within 200 km of the edge of thick lithosphere, irrespective of the age of mineralisation. This implies long-term craton edge stability, forcing a reconsideration of basin dynamics and the sediment-hosted mineral system. We find that the thermochemical structure of thick lithosphere results in increased basin subsidence rates during rifting, coupled with low geothermal gradients, which ensure favourable metal solubility and precipitation. Sediments in such basins generally contain all necessary lithofacies of the mineral system. These considerations allow establishment of the first-ever national prospectus for sediment-hosted base metal discovery. Conservative estimates place the undiscovered resource of sediment-hosted base metals in Australia to be ~50–200 Mt of metal. Importantly, this work suggests that ~15% of Australia is prospective for giant sediment-hosted deposits; we suggest that exploration efforts should be focused in this area. <b>Citation:</b> Czarnota, K., Hoggard, M.J., Richards, F.D., Teh, M., Huston, D.L., Jaques, A.L. and Ghelichkhan, S., 2020. Minerals on the edge: sediment-hosted base metal endowment above steps in lithospheric thickness. 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.

<div>Geological maps are powerful models for visualizing the complex distribution of rock types through space and time. However, the descriptive information that forms the basis for a preferred map interpretation is typically stored in geological map databases as unstructured text data that are difficult to use in practice. Herein we apply natural language processing (NLP) to geoscientific text data from Canada, the U.S., and Australia to address that knowledge gap. First, rock descriptions, geological ages, lithostratigraphic and lithodemic information, and other long-form text data are translated to numerical vectors, i.e., a word embedding, using a geoscience language model. Network analysis of word associations, nearest neighbors, and principal component analysis are then used to extract meaningful semantic relationships between rock types. We further demonstrate using simple Naive Bayes classifiers and the area under receiver operating characteristics plots (AUC) how word vectors can be used to: (1) predict the locations of “pegmatitic” (AUC = 0.962) and “alkalic” (AUC = 0.938) rocks; (2) predict mineral potential for Mississippi-Valley-type (AUC = 0.868) and clastic-dominated (AUC = 0.809) Zn-Pb deposits; and (3) search geoscientific text data for analogues of the giant Mount Isa clastic-dominated Zn-Pb deposit using the cosine similarities between word vectors. This form of semantic search is a promising NLP approach for assessing mineral potential with limited training data. Overall, the results highlight how geoscience language models and NLP can be used to extract new knowledge from unstructured text data and reduce the mineral exploration search space for critical raw materials.</div><div><br></div><div><strong>Citation: </strong>Lawley, C. J. M., Gadd, M. G., Parsa, M., Lederer, G. W., Graham, G. E., and Ford, A., 2023, Applications of Natural Language Processing to Geoscience Text Data and Prospectivity Modeling: Natural Resources Research. https://doi.org/10.1007/s11053-023-10216-1</div>

<p>This record presents new zircon and titanite U–Pb geochronological data, obtained via Sensitive High Resolution Ion Microprobe (SHRIMP) for twelve samples of plutonic and volcanic rocks from the Lachlan Orogen and the New England Orogen, and two samples of hydrothermal quartz veins from the Cobar region. Many of these new ages improve existing constraints on the timing of mineralisation in New South Wales, as part of an ongoing Geochronology Project (Metals in Time), conducted by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) under a National Collaborative Framework (NCF) agreement. The results herein (summarised in Table 1.1 and Table 1.2) correspond to zircon and titanite U–Pb SHRIMP analysis undertaken on GSNSW mineral systems projects for the reporting period July 2016–June 2017. Lachlan Orogen <p>The Lachlan Orogen samples reported herein are sourced from operating mines, active prospects, or regions with historical workings. The new dates constrain timing of mineralisation by dating the units which host or crosscut mineralisation, thereby improving understanding of the mineralising systems, and provide stronger constraints for mineralisation models. <p>In the eastern Lachlan Orogen, the new dates of 403.9 ± 2.6 Ma for the Whipstick Monzogranite south of Bega, and 413.3 ± 1.8 Ma for the Banshea Granite north of Goulburn both provide maximum age constraints for the mineralisation they host (Whipstick gold prospect and Ruby Creek silver prospect, respectively). At the Paupong prospect south of Jindabyne, gold mineralisation is cut by a dyke with a magmatic crystallisation age of 430.9 ± 2.1 Ma, establishing a minimum age for the system. <p>The 431.1 ± 1.8 Ma unnamed andesite and the 428.4 ± 1.9 Ma unnamed felsic dyke at the Dobroyde prospect 10 km north of Junee are just barely distinguishable in age, in the order that is supported by field relationships. The andesite is the same age as the c. 432 Ma Junawarra Volcanics but has different geochemical composition, and is younger than the c. 437 Ma Gidginbung Volcanics. The two unnamed units pre-date mineralisation, and are consistent with Pb-dating indicating a Tabberaberran age for mineralisation at the Dobroyde gold deposit. <p>Similarly, the 430.5 ± 3.4 Ma leucogranite from Hickory Hill prospect (north of Albury) clarifies that this unit originally logged as Jindera Granite (since dated at 403.4 ± 2.6 Ma) is instead affiliated with the nearby Mount Royal Granite, which has implications for the extent of mineralisation hosted within this unit. <p>Cobar Basin <p>Titanite ages of 382.5 ± 2.6 Ma and 383.4 ± 2.9 Ma from hydrothermal quartz veins that crosscut and postdate the main phase of mineralisation at the Hera mine in the Cobar region constrain the minimum age for mineralisation. These ages are indistinguishable from a muscovite age of 381.9 ± 2.2 Ma interpreted to be related to late- or post-Tabberaberan deformation event, and these results indicate that mineralisation occurred at or prior to this deformation event. <p>New England Orogen <p>The new ages from granites of the New England Orogen presented in this record aid in classification of these plutons into various Suites and Supersuites, and these new or confirmed relationships are described in detail in Bryant (2017). Many of these plutons host mineralisation, so the new ages also provide maximum age constraints in the timing of that mineralisation. <p>The 256.1 ± 1.3 Ma age of the Deepwater Syenogranite 40 km north of Glen Innes indicates that it is coeval with the 256.4 ± 1.6 Ma (Black, 2006) Arranmor Ignimbrite Member (Emmaville Volcanics) that it intrudes, demonstrating that both intrusive and extrusive magmatism was occurring in the Deepwater region at the same time. The 252.0 ± 1.2 Ma age for the Black Snake Creek Granite northeast of Tenterfield is consistent with its intrusive relationship with the Dundee Rhyodacite (254.34 ± 0.34 Ma; Brownlow et al., 2010). Similarly, the 251.2 ± 1.3 Ma age for the Malara Quartz Monzodiorite southeast of Tenterfield is consistent with field relationships that demonstrate that it intrudes the Drake Volcanics (265.3 ± 1.4 Ma–264.4 ± 2.5 Ma, Cross and Blevin, 2010; Waltenberg et al., 2016). <p>The 246.7 ± 1.5 Ma Cullens Creek Granite north of Drake was dated in an attempt to provide a stronger age constraint on mineral deposits that also cut the Rivertree and Koreelan Creek plutons (249.1 ± 1.3 Ma and 246.3 ± 1.4 Ma respectively, Chisholm et al., 2014a). However, the new age is indistinguishable from the Koreelan Creek Granodiorite, and timing of mineralisation is not further constrained, but the new age demonstrates a temporal association between the Cullens Creek and Koreelan Creek plutons. <p>The 239.1 ± 1.2 Ma age for the Mann River Leucogranite west of Grafton is indistinguishable in age from plutons in the Dandahra Suite and supports its inclusion in this grouping. The new age also constrains the timing of the distal part of the Dalmorton Gold Field, and implies that the gold vein system postdates the Hunter-Bowen orogeny. <p>The 232.7 ± 1.0 Ma Botumburra Range Monzogranite east of Armidale is younger than most southern New England granites, but this age is very consistent with the Coastal Granite Association (CGA), and the new age, along with the previously noted petrographic similarities (Leitch and McDougall, 1979) supports incorporation of the Botumburra Range Monzogranite into the Carrai Supersuite of the CGA (Bryant, 2017).

<div>The Exploring for the Future (EFTF) program is an Australian government initiative aimed at stimulating investment in resource exploration and development. It operates multiple interconnected projects, such as the Australia’s Resources Framework (ARF), a continental-scale endeavor to enhance understanding of Australia's geology and resource potential. A module of ARF, the Geochemistry for Basin Prospectivity (G4BP), studies Australian basins with prospective base metal mineral systems. </div><div><br></div><div>The current report focuses on the Neoproterozoic segment of the Stuart Shelf region in South Australia, a part of the Adelaide Rift Complex. This research is conducted collaboratively with the Geological Survey of South Australia, examining sediment-hosted copper potential in the rift complex.</div><div><br></div><div>The Adelaide Rift Complex is a geological formation that underwent extensive sedimentation from the Neoproterozoic to early Cambrian, particularly within the rift zone. Stuart Shelf sediments overlay Mesoproterozoic magmatic and Paleoproterozoic metasediment layers. The complex hosts multiple copper deposits, which are usually associated with movement of basinal brines that leach metals from lower basinal layers or rift-related volcanic rocks.</div><div><br></div><div>To improve understanding of the geology of the Stuart Shelf and related copper mineralisation, two primary objectives were set: </div><div><br></div><div>1. Geochemical fingerprinting and baseline data collection: This involves compilation and reanalysis of existing data, along with new data collection aimed at providing comprehensive geochemical data for stratigraphic units within the Stuart Shelf.</div><div><br></div><div>2. Identification of mineral system components: Utilising data from the first objective, this phase aims to identify potential metal and fluid sources and potential sites of metal deposition. </div><div>In conjunction with these efforts, a GA-GSSA geochemical sampling project is underway, tying geochemistry to lithostratigraphic units and facies. The newly acquired geochemical data will be integrated into the overall GSSA-CSIRO project to contribute to a more comprehensive understanding of the sediment-hosted stratabound mineral system.</div><div><br></div>

<div>The footprint of a mineral system is potentially detectable at a range of scales and lithospheric depths, reflecting the size and distribution of its components. Magnetotellurics is one of a few techniques that can provide multiscale datasets to understand mineral systems. The Australian Lithospheric Architecture Magnetotelluric Project (AusLAMP) is a collaborative national survey that acquires long-period magnetotelluric data on a half-degree grid spacing (about 55 km) across Australia. This project aims to map the electrical conductivity/resistivity structure in the crust and mantle beneath the Australian continent. We have used AusLAMP as a first-order reconnaissance survey to resolve large-scale lithospheric architecture for mapping areas of mineral potential in Australia. AusLAMP results show a remarkable connection between conductive anomalies and giant mineral deposits in known highly endowed mineral provinces. Similar conductive features are mapped in greenfield areas where mineralisation has not been previously recognised. In these areas we can then undertake higher-resolution infill magnetotelluric surveys to refine the geometry of major structures, and to investigate if deep conductive structures are connected to the near surface by crustal-scale fluid-flow pathways.</div><div> We summarise the results from a 3D resistivity model derived from AusLAMP data in Northern Australia. This model reveals a broad conductivity anomaly in the lower crust and upper mantle that extends beneath an undercover exploration frontier between the producing Tennant Creek region and the prospective Murphy Province. This anomaly potentially represents a fertile source region for mineral systems. A subsequent higher-resolution infill magnetotelluric survey revealed two prominent conductors within the crust whose combined responses produced the lithospheric-scale conductivity anomaly mapped in the AusLAMP model. Integration of the conductivity structure with deep seismic reflection data revealed a favourable crustal architecture linking the lower, fertile source regions with potential depositional sites in the upper crust. Integration with other geophysical and geochronological datasets suggests high prospectivity for major mineral deposits in the vicinity of major faults.</div><div> This study demonstrates that the integration of geophysical data from multiscale surveys is an effective approach to scale reduction during mineral exploration in covered terranes.</div> This Abstract was submitted to and presented at the 6th International Archean Symposium Target 2023, 28 July (https://6ias.org/target2023/)

<div>Maps showing the potential for carbonatite-related rare earth element (REE) mineral systems in Australia. Each of the mineral potential maps is a synthesis of three or four component layers. Model 1 integrates three components: sources of metals, energy drivers, and lithospheric architecture. Model 2 integrates four components: sources of metals, energy drivers, lithospheric architecture, and ore deposition. Both models use a hybrid data-driven and knowledge driven methodology to produce the final mineral potential map for the mineral system. An uncertainty map is provided in conjunction with the mineral potential map for Model 2 that represents the availability of data coverage over Australia for the selected combination of input maps. Uncertainty values range between 0 and 1, with higher uncertainty values being located in areas where more input maps are missing data or have unknown values. An assessment criteria table is provided and contains information on the map creation.</div>

<div>As part of the Delamerian Margins NSW National Drilling Initiative campaign, seventeen stratigraphic boreholes were drilled between Broken Hill and Wentworth, in Western NSW. These holes were designed to test stratigraphic, structural, and mineral systems questions in the New South Wales portion of the Delamerian Margin. Drilling was conducted between March and June 2023 and was undertaken by Geoscience Australia in collaboration with MinEx CRC. This report outlines basic borehole targeting rationale, borehole metadata, and analyses performed immediately following drilling to accompany data available through the Geoscience Australia portal.</div><div><br></div><div>Geoscience Australia’s Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government.</div>

<div>Australian sediment-hosted mineral systems are important sources of base metals and critical minerals that are vital to delivering Australia’s low-carbon economy. In Australia, sediment-hosted resources account for ~82% and ~86% of the total zinc (Zn) and lead (Pb) resources respectively. Given their significance to the Australian economy, four national-scale mineral potential models for sediment-hosted Zn-Pb mineral systems have been developed: clastic-dominated siliciclastic carbonate, clastic-dominated siliciclastic mafic, Mississippi Valley-type and Irish-type. In addition to the potential for Zn-Pb mineralisation, the uncertainty related to data availability has been examined. The mineral potential models were created using a mineral systems-based approach where mappable criteria have been used to assess the prospectivity of each system. Each model has been derived from a large volume of precompetitive geoscience data. The clastic-dominated siliciclastic carbonate mineral potential model predicts 92% of known deposits and occurrences within 15.5% of the area, the clastic-dominated siliciclastic mafic mineral potential model predicts 85% of deposits and occurrences within 27% of the area, and the Mississippi Valley-type mineral potential model predicts 66% of known deposits and occurrences within 31% of the area. Each model successfully predict the location of major sediment-hosted Zn-Pb deposits while highlighting new areas of elevated prospectivity in under-explored regions of Australia, reducing the exploration search space by up to 85% for sediment-hosted Zn-Pb mineral systems.</div>