Pooncarie Explanatory Notes (1996)

Abstract

The area lies within the eastern part of the Murray Basin. Most of that area consists of fluvial and marine Tertiary sedimentary units deposited in an intracratonic setting. Sediment thickness varies from 80m to 150m overlying basement highs and from 280m to 320m within basement troughs. Outcropping basement rocks occur in two parts of the area: Manfred Range and 'Springhill' property. The buried pre-Tertiary surface consists of a series of elongated ridges and valleys. The major palaeo-physiographic features, some of which are structural, have been identified. There are two aquifier-bearing depositionl sequences within the Tertiary succession. At least four forms of capping silcrete are present. They formed on outcropping Plio-Pleistocene clay-cemented quartz arenites, primarily the Parilla Sand, probably around 0.7 Ma to 0.4 Ma ago. Nearby Pliocence-hosted heavy mineral sands deposits are potential sources of titania for the silcretes. The extensive, flat, semi-arid Pooncarie map area is areally dominated by interacting Quaternary morphostratigraphic units of aeolian, lacustrine and fluvial depositional systems that are now largely inactive. Pliocene marine Loxton Sands - hosted heavy mineral sand deposits were formed as beach placers in topographic embayments. These deposits are presently considered sub-economic. Other mineral deposits, albeit also of limited economic potential, include gypsum and oolitic iron deposits, and lignite. A bentonite deposit, however, at Arumpo has considerable potential.

Reference

Cameron R.G. (Facer R.A. ed.) 1996. Geology of Pooncarie 1:250 000 map. Geological Survey of New South Wales, Sydney, xii + 108 pp.