The middle to lower Jurassic sequence in Australia's Surat Basin has been identified as a potential reservoir system for geological CO2 storage. The sequence comprises three major formations with distinctly different mineral compositions, and generally low salinity formation water (TDS<3000 mg/L). Differing geochemical responses between the formations are expected during geological CO2 storage. However, given the prevailing use of saline reservoirs in CCS projects elsewhere, limited data are available on CO2-water-rock dynamics during CO2 storage in such low-salinity formations. Here, a combined batch experiment and numerical modelling approach is used to characterise reaction pathways and to identify geochemical tracers of CO2 migration in the low-salinity Jurassic sandstone units. Reservoir system mineralogy was characterized for 66 core samples from stratigraphic well GSQ Chinchilla 4, and six representative samples were reacted with synthetic formation water and high-purity CO2 for up to 27 days at a range of pressures. Low formation water salinity, temperature, and mineralization yield high solubility trapping capacity (1.18 mol/L at 45°C, 100 bar), while the paucity of divalent cations in groundwater and the silicate reservoir matrix results in very low mineral trapping capacity under storage conditions. Formation water alkalinity buffers pH at elevated CO2 pressures and exerts control on mineral dissolution rates. Non-radiogenic, regional groundwater-like 87Sr/86Sr values (0.7048-0.7066) indicate carbonate and authigenic clay dissolution as the primary reaction pathways regulating solution composition, with limited dissolution of the clastic matrix during the incubations. Several geochemical tracers are mobilised in concentrations greater than found in regional groundwater, most notably cobalt, concentrations of which are significantly elevated regardless of CO2 pressure or sample mineralogy.

The Upper Burdekin Chloride Mass Balance Recharge web service depicts the recharge rates have been estimated at borehole locations in the Nulla and McBride basalt provinces. Using rainfall rates, rainfall chemistry and groundwater chemistry, the recharge rates have been estimated through the Chloride Mass Balance approach.

This grid dataset is an estimation of the relative surface potential for recharge within the Nulla Basalt Province. This process combined numerous factors together as to highlight the areas likely to have higher potential for recharge to occur. Soil permeability and surface geology are the primary inputs. Vegetation and slope were excluded from consideration, as these were considered to add too much complexity. Furthermore, this model does not include rainfall intensity – although this is known to vary spatially through average rainfall grids, this model is a depiction of the ground ability for recharge to occur should a significant rainfall event occur in each location. The relative surface potential recharge presented is estimated through a combination of soil and geological factors, weighting regions that are considered likely to have greater potential for recharge (e.g. younger basalts, vent-proximal facies, and highly permeable soils). Near-surface permeability of soil layers has been considered as a quantified input to the ability for water to infiltrate soil strata. It was hypothesised that locations proximal to volcanic vents would be preferential recharge sites, due to deeply penetrative columnar jointing. This suggestion is based on observations in South Iceland, where fully-penetrating columnar joint sets are more prevalent in proximal facies compared to distal facies in South Iceland (Bergh & Sigvaldson 1991). To incorporate this concept, preferential recharge sites are assumed to be within the polygons of vent-proximal facies as derived from detailed geological mapping datasets. Remaining geology has been categorised to provide higher potential recharge through younger lava flows. As such, a ranking between geological units has been used to provide the variation in potential recharge estimates. <b>Reference</b> Bergh, S. G., & Sigvaldason, G. E. (1991). Pleistocene mass-flow deposits of basaltic hyaloclastite on a shallow submarine shelf, South Iceland. Bulletin of Volcanology, 53(8), 597-611. doi:10.1007/bf00493688

In 2017, Queensland Fire and Emergency Services (QFES) completed the State Natural Hazard Risk Assessment which evaluated the risks presented to Queensland by seven in-scope natural hazards. This publication can be found at www.disaster.qld.gov.au. The risks presented by tsunami were not evaluated as part of this assessment as there were State and Commonwealth projects underway at the time that would better inform the understanding of the hazard. These have since been completed and now underpin this guide. Following the release of the State Natural Hazard Risk Assessment and through consultation with stakeholders at all levels of Queensland’s Disaster Management Arrangements, the need for consistent information regarding Queensland’s risk from tsunami impact and inundation was identified. Accordingly, this Tsunami Guide for Queensland was developed, with support from Geoscience Australia and the Department of Environment and Science’s Coastal Impacts Unit (CIU), through a consultative process which also helped contextualise the findings of Geoscience Australia’s Probabilistic Tsunami Hazard Assessment 2018 (PTHA18) for Queensland.

Interpretation of the Thomson Orogen and its context within the Tasmanides of eastern Australia is hampered by vast areas of deep sedimentary cover which also mask potential relationships between central and eastern Australia. Within covered areas, basement drill cores offer the only direct geological information. This study presents new detrital zircon isotopic data for these drill cores and poorly understood outcropping units to provide new age and provenance information on the Thomson Orogen. Two distinct detrital zircon signatures are revealed. One is dominated by Grenvillian-aged (1300900 Ma) zircons with a significant peak at ~1180 Ma and lesser peak at ~1070 Ma. These age peaks, along with Lu-Hf isotopic compositions (median Hf(t) = +1.5), dominantly mantle-like 18O values (median = 5.53) and model ages of ~1.89 Ga, support a Musgrave Province (central Australia) source. The dominance of Grenvillian-aged material additionally points to deposition during the Petermann Orogney (570530 Ma) when the Musgrave Province was uplifted shedding abundant material to the Centralian Superbasin. Comparable age spectra suggest that parts of the Thomson Orogen were connected to the Centralian Superbasin during this period. We use the term `Syn-Petermann to describe this signature which is observed in two drill cores adjacent to the North Australian Craton and scattered units in the outcropping Thomson Orogen. The second signature marks a significant provenance shift and is remarkably consistent throughout the Thomson Orogen. Age spectra exhibit dominant peaks at 600560 Ma, lesser 1300900 Ma populations and maximum depositional ages of ~496 Ma. This pattern is termed the `Pacific Gondwana detrital zircon signature and is recognised throughout eastern Australia, Antarctica and central Australia. LuHf isotope data for Thomson Orogen rocks with this signature is highly variable with Hf(t) values between -49 and +10 and dominantly supracrustal 18O values suggesting input from different and more diverse source regions.

This GA Record is one of a series of 4 reports completed by the GA Groundwater Group under the National Collaboration Framework Project Agreement with the Office of Water Science (Dept of the Environment). The report was originally submitted to OWS as a GA Professional Opinion, and was subsequently reviewed by Queensland government. The Laura Basin in north Queensland is a priority coal-bearing sedimentary basin that is not currently slated for Bioregional Assessment.

This GA Record report is one of a series of 4 reports undertaken by the GA Groundwater Group under the National Collaboration Framework Project Agreement with the Office of Water Science (in the Department of the Environment). The report was originally submitted to the OWS in July 2013, and subsequently reviewed by Queensland government. The Maryborough Basin in Queensland is a priority coal-bearing sedimentary basin that is not currently slated for Bioregional Assessment.

From June 23rd to November 4th 2016 Geotech Ltd. carried out a helicopter-borne geophysical survey over part of East Isa in Queensland (figure 1). Operations were based at Cloncurry, Queensland. The traverse lines were flown in an east to west (N 90° E azimuth) direction with 2km and 2.5km traverse line spacings, with three Tie lines flown perpendicular to the traverse lines. During the survey the helicopter was maintained at a mean altitude of 76 metres above the ground with an average survey speed of 90 km/hour. This allowed for an actual average EM Transmitter-receiver loop terrain clearance of 38 metres and a magnetic sensor clearance of 68 metres. The principal geophysical sensors included a versatile time domain electromagnetic (VTEMTMPlus) full receiver-waveform system, and a caesium magnetometer. Ancillary equipment included a GPS navigation system, laser and radar altimeters, and inclinometer. A total of 15697 line-kilometres of geophysical data were acquired during the survey. The electromagnetic system is a Geotech Time Domain EM (VTEMplus) with full receiver-waveform streamed data recording at 192 kHz. The "full waveform VTEM system" uses the streamed half-cycle recording of transmitter current and receiver voltage waveforms to obtain a complete system response calibration throughout the entire survey flight. The VTEM transmitter loop and Z-component receiver coils are in a concentric-coplanar configuration and their axes are nominally vertical. An X-component receiver coil is also installed in the centre of the transmitter loop, with its axis nominally horizontal and in the flight line direction. The receiver coils measure the dB/dt response, and a B-Field response is calculated during the data processing. In-field data quality assurance and preliminary processing were carried out on a daily basis during the acquisition phase. Preliminary and final data processing, including generation of final digital data products were undertaken from the office of Geotech Ltd. in Aurora, Ontario. A set of Conductivity Depth Images (CDI) were generated using EM Flow version 3.3, developed by Encom Technologies Pty Ltd. A total of forty-five (45) dB/dt Z component channels, starting from channel 4 (21 µsec) to channel 48 (10667 µsec), were used for the CDI calculation. An averaged waveform at the receiver was used for the calculation since it was consistent for the majority of the flights with minor deviation from the average. Digital data includes all electromagnetic and magnetic data, conductivity imaging products, mulitplots plus ancillary data including the waveform.

This report presents key results of groundwater level interpretations 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. This report interprets groundwater levels measured in both provinces by Geoscience Australia and the Queensland Government to provide recommendations for resource management. The NBP and MBP basalt aquifers are heterogeneous, fractured, vesicular systems. Several lava flows are mapped at surface in both provinces, and the degree of hydraulic connectivity between these flows is unclear. Although there was some uncertainty due to monitoring well construction issues, barometric efficiency analyses from supporting project documents suggest that the basalts of the NBP and MBP were unconfined where monitored during the EFTF project. That finding generally matches observations presented here. Longer term groundwater hydrographs suggest that groundwater levels have been declining in the NBP and MBP following major flooding in 2010-2011 related to one of the strongest La Niña events on record. Groundwater levels are yet to decline to pre-flood elevations in places. Importantly, these longer term hydrographs set the project in context: the EFTF monitoring period is only a small fraction of a much longer-functioning, dynamic groundwater system. Nulla Basalt Province The NBP is elongated east-west, and is situated entirely within the Burdekin River catchment. Volcanic vents in the west identify that area as the main extrusive centre. Regionally, groundwater migrates through the basalts of the NBP from the western high ground towards the Burdekin River in the east. Although lava flows of the NBP reach the Burdekin River, direct groundwater discharge in this area has not yet been proven. However, groundwater does discharge to various springs and surface watercourses in the NBP that are known tributaries of the Burdekin River. Despite the presence of many registered extraction bores, no clear signs of pumping were observed in groundwater hydrographs from the NBP during the EFTF monitoring period. Water levels in many bores responded to major rainfall events, ranging from a simple change in declining hydrograph slope to a water level increase of ~6.8 m in the central west. While some responses could have been induced by loading, electrical conductivity loggers and the extent of water level rise showed that many were clearly caused by recharge. At nested monitoring locations, groundwater levels remained commensurate with downward flow potentials throughout the EFTF monitoring period. McBride Basalt Province The MBP is approximately circular in plan, with volcanic vents present in a north-northeast trending band through the province centre. Lava flows extend away from the high ground of the province centre towards lower ground near the edges. In part due to its geometry, the MBP is situated within four river catchments; only surface water landing in the east flows into the Burdekin River. Regionally, groundwater migrates through the basalts of the MBP from the central high ground radially towards the edges. Direct groundwater discharge from the MBP basalts into the Burdekin River has been shown in this project. Similarly to the NBP, groundwater is also known to discharge to numerous springs and surface watercourses in the MBP. Water levels in many bores responded to major rainfall events. Responses ranged from a change in declining hydrograph slope to a water level increase of ~6.8 m in the southeast. While some responses could have been induced by loading, the extent of water level rise showed that others were clearly caused by recharge. No nested monitoring locations were installed for the EFTF project, so vertical head gradients are currently unknown. Although there are numerous registered extraction bores in the MBP, groundwater level response to pumping was only definitively identified in the east in bore RN12010016. However, several registered bores with high estimated yields have been installed in the northeast since EFTF fieldwork completion. It is possible that these higher yielding extraction bores may induce visible drawdown in monitoring bores in the future. Their high estimated yields may be associated with lava tubes; features not reported in the literature reviewed for this project for the NBP, but identified at surface and potentially in several Queensland Government bores drilled in the MBP. Conclusions and recommendations The Upper Burdekin Groundwater Project has provided abundant information on various aspects of the hydrogeology of the Nulla and McBride basalt provinces. General groundwater flow processes are understood at a regional scale for the EFTF monitoring period, but more detailed investigations and longer term monitoring are required to fully evaluate local conditions. One of the main observations of this study are the long term groundwater level declines in both the NBP and MBP following the 2010-2011 La Niña-associated floods. Groundwater levels are yet to reduce to pre-flood elevations in places, showing that the EFTF monitoring period represents only a small fraction of a much longer-functioning, dynamic groundwater system. It is unclear what, if any, contribution groundwater extraction has made to regional water level declines. Numerous correlations were assessed between groundwater hydrograph characteristics and potentially influencing factors, but the results were mostly inconclusive. There is uncertainty in hydraulic connectivity across lava flow boundaries and between intra-lava flow aquifers. Although interesting groundwater processes were identified at many bores, at the current bore spacing it is not generally possible to interpolate between locations with any certainty. Knowledge gaps and suggestions for further investigation are recorded in Section 5 of the report. The gaps identified should assist planning of future work to inform: - Further characterisation of groundwater resources. - Protection of groundwater dependent ecosystems. - Appropriate groundwater resource management.

The Upper Burdekin Chloride Mass Balance Recharge web service depicts the recharge rates have been estimated at borehole locations in the Nulla and McBride basalt provinces. Using rainfall rates, rainfall chemistry and groundwater chemistry, the recharge rates have been estimated through the Chloride Mass Balance approach.