Towards a Geochronology for Long-term Landscape Evolution, Northwestern New South Wales

Abstract

The study area extends from west of the Great Divide to the Broken Hill and Tibooburra regions of far western New South Wales, encompassing several important mining districts that not only include the famous Broken Hill lodes (Pb-Zn-Ag), but also Parkes (Cu-Au), Peak Hill (Au), Cobar (Cu-Au-Zn) and White Cliffs (opal). The area is generally semi-arid to arid undulating to flat terrain covered by sparse vegetation. ¶ During the Cretaceous, an extensive sea retreated across vast plains, with rivers draining from the south and east. After the uplift of the Great Divide associated with opening of the Tasman Sea in the Late Cretaceous, drainage swung to the west, cutting across the Darling River Lineament. The Murray-Darling Basin depression developed as a depocentre during the Paleogene. Climates also underwent dramatic change during the Cenozoic, from warm-humid to cooler, more seasonal climates, to the arid conditions prevalent today. Up until now, there has been very little temporal constraint on the development of this landscape over this time period. This study seeks to address the timing of various weathering and landscape evolution events in northwestern New South Wales. ¶ ...