b'AEGC 2023Short abstractsGeomechanical simulation to model creep deformationmodelling reveals the calcite and albite were dissolved, solution of salt formation. pH decreases from initially 8.5 to ~4.5 as CO 2added, while dawsonite mineral forming as a response to this dissolution.Princy Agrahari1 Partha Pratim Mandal2, Mustafa Sari3and Joel Sarout3Geometry of the North Australian Craton margins and 1 IIT (ISM) Dhanbadcorrelations with upper crustal structures.2 Qeye 3 CSIRO Fatemeh Amirpoorsaeed, Peter Betts, Robin Armit, Alexander Cruden and Anindita SamsuTo combat the increasing demand of renewable energy, development of effective systems for energy storage is needed.Monash UniversitySalt caverns serve as a feasible and efficient solution for hydrogen storage in the subsurface. Studying the microstructure andThe margins of the North Australian Craton (NAC) are major analysing the deformation behaviour of these formationslithospheric boundaries corresponding to zones of intense requires clear geological domain knowledge, suitable numericalfaulting in the upper crust. The sutures defining the edges of techniques, and adequate computational models to predict thethe eastern and southern margin of the NAC are characterised long-term response of the host formation and associated stressby fundamentally different geometries. The eastern margin is state. In this work, a 2D finite element simulator code was usedcharacterised by a west-dipping geometry that dips toward the to probe the deformation characteristics of samples from theinterior of the craton (inward), whereas the southern margin Frome Rocks salt formation, Canning Basin, Western Australia.dip to the south away from the craton interior (outward). The Two situations are considered: (i) creep under monotonic loading,causes of these different geometries are not well-understood and (ii) creep under cyclic loading with the aim to investigateand nor is their influence on later phases of deformation. the influence of non-linear primary creep and perturbationHere we used gravity, magnetic and seismic reflection data in stress magnitudes under in-situ conditions. Damage andto investigate the influence of the NAC margin geometry on creep constitutive laws like generalised Hookes Law, totalthe distribution and connectivity of structures in the upper potential energy principle, infinitesimal deformation theory etccrust. The geophysical data are used to interpret major crustal are utilised in the simulation engine assuming constant strainboundaries, including major sutures and shallow structures.triangle elements. With suitable boundary conditions, the modelThree major structures occur on the eastern margin of Mount Isa captures the creep deformation under monotonic loading whenInlier: the Gidyea Suture Zone, the Pilgrim Fault Zone, and the compared to experimental data. A good match of compressiveWestern Edge Fault. Each of these major structures dips towards axial deformation is observed between experimental andthe interior of the craton. Our interpretation reveals the presence of numerical results. Sensitivity of the parameters involved inshallow listric structures that sole out into regional decollements, the creep and damage constitutive laws are also thoroughlywhich are antithetic to the major crustal penetrating faults. We investigated. Finally, the impact of cyclic loading on the saltobserve two major sutures along the southern margin of the NAC, formation is analysed considering distribution of three principalArunta Inlier: the Willowra Ridge and the Warrumpi Suture. The stress components at sampling depth. Willowra Ridge represents the southernmost edge of the NAC. Seismic reflection data reveals that the structural style is very different to that of Mount Isa. Faults in the footwall of Willowra Experimental investigation and geochemicalRidge are more widely spaced and extend down to the Moho. interpretation of in-situ formed carbonated brine/ There is no obvious link between the geometry of this margin and sandstone interaction: Implication of CO 2geo- upper crustal structures. By comparing these two margins, we can sequestration. establish a relationship between the structural architecture and the geometry of the craton margin.Duraid Al-bayati 1,2, Ali Saeedi1, Matthew Myers 3 and Reza Rezaee11 Curtin UniversityIs a reinterpretation of the basin architecture for the 2 University of Kirkuk 3 CSIRO Perth Basin required? A case study of how reprocessed Geo-sequestration of carbon dioxide into undergroundgravity and magnetic data is providing critical new geological structure is widely accepted process to minimiseinsights.the current greenhouse gas emissions. Injected CO 2could be immobilised by the following tapping mechanisms; structuralHelen Anderson 1 Jane Cunneen2, Rainer Wackerle3, Peter Hoiles4 trapping, dissolution in the in-situ solution, trapped by theand Simon Crellin1capillary forces, and solidified by chemical reactions with1 Searcher the host rock. Both mineral and aqueous trapping lead to2 Basin Scope Consulting transforming CO 2into less mobile forms, effectively providing3 GeoIntrepidNamibia permanent sequestration. The latter forms an acidic environment4 Discover Geosciencein which some minerals would react, and the released cations may form new minerals. Chemical interactions may accompanyGovernment and industry publications on the architecture as a reactive in-situ solute come in contact with rock. The resultsof the Perth Basin typically include structural and tectonic showed a measurable reduction in the post-flood permeabilityboundaries derived prior to 2000 using regional data, (~5 mD) caused by the precipitation of some minerals anddespite more modern data being available. In 2021, Searcher blocking of pore throats. On the other hand a subtle increaseembarked on a project to merge and reprocess of all existing in sample porosity (~0.25%) were observed mainly due to claygravity and magnetic data in the northern Perth Basin, and carbonate minerals dissolution. Geochemical reactionincluding detailed ground gravity and 11 airborne gravity FEBRUARY 2023 PREVIEW 78'