The Tertiary stratigraphic palynology of the Murray Basin in New South Wales. 1. The Hay-Balranald-Wakool districts

The Hay, Balranald and Wakool districts are situated on entirely non-marine sediments, to the east of the limit of marine transgression of the Murray Basin.This palynological study of ten selected bores relates the sediments to the geological time scale by correlating the assemblages with the spore-pollen zones described for the Gippsland Basin.In this part of New South Wales, the deepest and oldest sediments, below 305m, are middle Eocene in age.Late Eocene assemblages are found below about 274m.Oligocene -early Miocene sediments form thick sections between approximate levels of 120m and 270m, and are encountered in every bore.Carbonaceous clays and lignites are common and the climate during deposition of these sediments must have been very humid, with lakes and swamps a feature of the landscape.Middle Miocene and younger assemblages have been recovered from only four of the bores examined.During deposition of the upper 100m, it appears that conditions were not favourable for pollen preservation.About the middle Miocene, the deposition of carbonaceous clays and lignites ceased and the rainfall must have decreased, although the continuance of the grey colour of the clays indicates that it was uniformly distributed through the year.with no marked dry season.