This Maryborough-Nambour Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus.
The Maryborough Basin is a half-graben intracratonic sag basin mainly filled with Early Cretaceous rocks, overlain by up to 100 m of Cenozoic sediments. It adjoins the older Nambour Basin to the south, comprising Triassic to Jurassic rocks. The boundary between the basins has shifted due to changes in sedimentary unit classifications, with the Cretaceous units now restricted to the Maryborough Basin and Jurassic and older units assigned to the Nambour Basin.
Both basins are bounded to the west and unconformably overlies older Permian and Triassic rocks in the Gympie Province and Wandilla Province of the New England Orogen. In the south of the Nambour Basin, it partly overlaps with the Triassic Ipswich Basin.
The Nambour Basin in the south is primarily composed of the Nambour Formation, with interbedded conglomerate, sandstone, siltstone, shale, and minor coal. Overlying this is the Landsborough Sandstone, a unit with continental, fluviatile sediments and a thickness of up to 450 m. In the north, the Duckinwilla Group contains the Myrtle Creek Sandstone and the Tiaro Coal Measures, which were formerly considered part of the Maryborough Basin but are now associated with the northern Nambour Basin.
In contrast, the Maryborough Basin consists of three main Cretaceous units and an upper Cenozoic unit. The Grahams Creek Formation is the deepest, featuring terrestrial volcanic rocks, volcaniclastic sedimentary rocks, and minor pyroclastic rocks. The overlying Maryborough Formation was deposited in a continental environment with subsequent marine incursion and includes mudstone, siltstone, minor sandstone, limestone, conglomerate, and tuff. The upper Cretaceous unit is the Burrum Coal Measures, comprising interbedded sedimentary rocks deposited in fluvial to deltaic environments. The uppermost unit, the Eocene to Miocene Elliott Formation, includes sandstone, siltstone, conglomerate, and shale deposited in fluvial to deltaic environments.
Cenozoic sediments overlying the Elliott Formation consist of Quaternary alluvium, coastal deposits, and sand islands like Fraser Island, influenced by eustatic sea level variations. Volcanic deposits and freshwater sediments also occur in some areas. Adjacent basins, such as the Clarence-Moreton Basin and Capricorn Basin, have stratigraphic correlations with the Maryborough Basin. The Oxley Basin lies to the south, overlying the Ipswich Basin.
In summary, the Maryborough Basin and the older Nambour Basin exhibit distinct geological characteristics, with varying rock formations, ages, and sedimentary features, contributing to the diverse landscape of the region.
