Diamantina River ring feature

22°09′S 141°54′E / 22.15°S 141.9°E / -22.15; 141.9 The Diamantina River ring feature is a geomorphic feature that consists of a conspicuous near-360° circular drainage pattern that forms the headwaters of the Diamantina River. It is centred near the Woodstock Station west of Winton, Channel Country, Central West Queensland. This geomorphic feature coincides with a potassium–thorium–uranium radiometric signature that is associated with exposed clay-rich sedimentary rocks of the Cretaceous Winton Formation, high-uranium elevated Cenozoic duricrust surfaces, and high-thorium elevated sediment eroded from the Cenozoic weathering profile. The Diamantina River ring feature is one of several circular crustal structures of diverse origin that have been mapped within Australia. These circular crustal structures include geologic structures such as tectonic domes, circular granite intrusions, volcanic calderas and ring structures, salt domes, impact structures and morphological drainage rings of unknown origin.^[1]

Beneath the Diamantina River ring feature, two seismic reflection sections exhibit a circa 100 kilometres (62 mi)-wide zone of anomalously moderately reflective to weakly reflective crust underlying flat–lying, undisturbed sedimentary strata. These sedimentary strata consist of the superimposed sedimentary basin fills of Jurassic–Cretaceous Eromanga and Permian–Triassic Galilee basins. The anomalous crust overlies a well-defined circa 39 to 45 kilometres (24 to 28 mi)-deep Mohorovičić discontinuity. This region of seismically non-reflective to weakly reflective crust separates crust of different seismic reflection character on either side. As discussed below, the nature of the seismic non-reflective crust is unknown.^[1][2][3]