Once all the surfaces are generated, the creation of each stratigraphic unit included in the 3D volumetric model commenced. Each model layer is constrained by its formation top surface and the top of the underlying unit. Even though the main structures were constrained using seismic surfaces, a more detailed structural fault-block modelling was not carried out during this study. Some cross sections were constructed intersecting faults nearly perpendicular to where the largest fault displacement was observed in the seismic surfaces in each regional fault. From these cross sections a comparison of aquifers/aquitards was made on both

sides of the faults, calculating the percentage of permeable units interfacing either permeable or impermeable units on the opposite side of the faults. This is a simple approach to assess the hydraulic character of faults. The 3D geological model of the Galilee PF-562271 molecular weight Basin and the central part of the Eromanga Basin was developed to assess the overall aquifer/aquitard geometry and the importance of structural features within CX-5461 mw the study area. A series of 23 cross sections was produced, and four of these (CS 04, CS 19, CS 20 and CS 23) are selected to highlight some key results of the model (Fig. 4), notably the thickness of the various formations, and their stratigraphic and geometric relationships relative to each other, particularly

where they are adjacent to faults. Cross Section 04 (Fig. 4a) shows the displacement of the Eromanga Basin units along the Hulton-Rand Structure and the abutment of the Galilee Basin against the same structure. Cross Section 19 (Fig. 4b)

shows a similar scenario to Cross Section 04 for the Tara Structure instead of the Hulton-Rand Structure, but also highlights the displacement Methocarbamol of the Eromanga Basin units through the Dariven Fault and displacement along the Cork Fault. However, the displacement along the Cork Fault could not be properly constrained as explained in Section 4.1.2. Cross Section 20 (Fig. 4c) shows an area where regional faults are not identified but where the Galilee Basin was continuous. Lastly, Cross Section 23 (Fig. 4d) shows an area, where the Galilee Basin is nearly absent and the Stormhill Fault and Westland Structure are identified. Additionally two newly defined faults (Thomson River and Lochern faults) are identified, which are likely to play a relevant role on groundwater movement. Due to the sparseness of wells, the identification of structures and their influence on geometric relationships between the stratigraphic units is based primarily on the seismic surfaces. Although structures can be easily recognised in these seismic surfaces (Fig. 5), it is difficult to determine the timing of movement for particular faults. However, through the assessment of vertical fault displacement of different units within the stratigraphic sequence, the understanding on the timing of regional fault movement can be refined (Fig. 5).