Shallow Precambrian crystalline basement underlies the greater part of the BARTON 1:250 000 map area. Thicker Neoproterozoic, Cambrian and Carboniferous Permian sediments occur in the northwest, with the southern margin bounded by the Karari...
Shallow Precambrian crystalline basement underlies the greater part of the BARTON 1:250 000 map area. Thicker Neoproterozoic, Cambrian and Carboniferous Permian sediments occur in the northwest, with the southern margin bounded by the Karari Fault Zone. Marine, estuarine, fluvial and lacustrine Tertiary and aeolian Quaternary sediments form an extensive but thin cover on very poorly exposed crystalline basement. Thin Jurassic and Cretaceous Bight Basin sediments are also inferred near Ifould Lake in the southwest. Aeromagnetic and gravity data have been used to subdivide the crystalline basement because the restricted outcrop has inhibited surface mapping. Archaean Mulgathing Complex which has a characteristic, subdued aeromagnetic signature underlies northern BARTON. These rocks include granulite facies para- and orthogneisses with distinctive northerly-trending isoclinal folds. Economic targets include gold within complex brittle fractures, and nickel sulphides in cumulus ultramafics. Palaeoproterozoic granitic to ultramafic intrusive bodies have a higher magnetic susceptibility than the Mulgathing Complex. These are interpreted to have intruded Mulgathing Complex during development of large-scale fault and shear zones. Regional northeasterly trending structures are clearly discordant to older basement. The age of the Fowler Suture Zone (southern BARTON) is currently constrained between 1730 and 1540 Ma, post emplacement of Hiltaba Suite granites and younger than traditionally accepted for the Kimban Orogeny in the eastern Gawler Craton. Anomalous base metals and platinoids occur in cumulus intermediate to mafic and ultramafic intrusives inferred to be contemporaneous with development of the Fowler Suture Zone. The extent of possible gold-bearing deformed Hiltaba Suite (approximately 1600 Ma) is uncertain. Officer Basin sediments have potential for hydrocarbons, potassium salts (in localised, restricted sub-basins) and base metals, particularly where the basin onlaps regional basement highs, i.e. along the Nawa Ridge in the northwestern corner of BARTON. Overlying Carboniferous Permian sediments are not coal- bearing. Late Eocene to Early Oligocene coastal dunes on the margin of the Eucla Basin (in particular sands of the Ooldea, Barton and Paling Ranges) are prospective for heavy mineral deposits. Potential exists for heavy minerals, transported in fluvial channels, to have been reworked and concentrated in high-energy beach environments along fossil strand lines. The fluvial palaeochannels also have potential for roll-front style uranium mineralisation and contain thin, uneconomic lignite seams.
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