Chapter 4 – Groundwater in the Murray Geological Basin - Assessment of Groundwater Resources in the Broken Hill Region

The Murray Geological Basin is a large but relatively shallow Cenozoic sedimentary basin, extending over 300,000 km of south-eastern Australia (Figure 4.1). Some 23,000 km of the Murray Geological Basin occurs within 150 km of Broken Hill (Figure 3.1), with the north-west margin of the basin adjacent to the fractured rock uplands where Broken Hill is located (Figure 4.2). Contours for the base of the Cenozoic sediment deposits within the basin show a dominant north-east trend, synonymous with the underlying infrabasins of the Tarrara, Menindee and Wentworth Troughs (Chapter 7). These are embayments to the main depositional centre for the Murray Geological Basin, the Renmark Trough, where over 600 metres of Cenozoic sediment has accumulated. The Renmark Trough is bounded to the west by the Hamley Fault, separating it from a smaller depression, called the Canegrass Lobe (Figure 4.2). Smaller north-east trending depressions also separate structural highs, such as the Redan Embayment between the Broken Hill Block and Scopes Range as well as the Bunnerungee Trough between the buried basement ridges of the Lake Victoria and Lake Wintlow Highs (Brodie, 1997). The Neckarboo Ridge, to the east of the Darling River, is a basement high that is traceable on the land surface by elevated dune fields, 10–20 km across.