Waite Creek Thrust Nappe—Western Ngalia Basin, Central Australia
A.T. Wells, F.J. Moss, 1983. "Waite Creek Thrust Nappe—Western Ngalia Basin, Central Australia", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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The seismic variable area cross section and interpretation presented (facing page) illustrate a typical profile of the thrusted northern margin of the Ngalia basin in central Australia. The seismic section is oriented approximately north to south, and is located at Waite Creek in the western part of the basin.
Apart from illustrating overthrust tectonics that are so characteristic of central Australian late Proterozoic to late Paleozoic intracratonic basins, the seismic record is unusual in showing a remarkably clear profile of the thrust fault.
The Ngalia basin underlies an area of 16,000 sq km (6,178 sq mi) between South lat. 22 to 23° and East long. 129 to 133°45'in the southern part of the Northern Territory, central Australia (Figure 1).
For the purposes of discussion and easy reference, the basin may be divided into three arbitrary zones which will be referred to in the text. They are a western zone, a central zone between East long. 131°25'and 132°, and an eastern zone.
The Ngalia basin is a structural feature comprising a wedge of predominantly arenaceous, late Proterozoic and Paleozoic sediments in an intracratonic downwarp in lower and middle Proterozoic igneous and metamorphic basement rocks, of the Arunta Block; in meridional cross section the basin structure is essentially a faulted asymmetrical syncline with the thickest sediments preserved toward the basins thrusted northern margin. The maximum known thicknesses of the sediments are: late Proterozoic 3,200 m (10,500 ft); Cambrian, 800 m (2,625 ft); Ordovician, 300 m (984 ft); Devono-Carboniferous, 3,100 m (10,171 ft). The thickest preserved sedimentary succession is 4,700 m (15,420 ft) in the northern part of the central basin zone. The sedimentary sequence is shown in Table 1.