Taphonomy and palaeoenvironmental interpretation of a late holocene deposit from Black's Point Sinkhole, Venus Bay, S.A

The deposit from Black's Point Sinkhole, Venus Bay Conservation Park, SA, represents a continuous 3500 year palaeontological and geological record for the late Holocene. Taphonomic analysis established the sinkhole as a pitfall trap. Palaeoenvironmental settings were deduced by analysing sediments and fauna. Age was assessed using carbon dating. Evidence suggests that around 4000BP precipitation was greater than present and the environment was dominated by closed canopy forests with an understorey and nearby mud flats. During this period fauna including Isoodon obesulus and Bettongia penicillata accumulated. From approximately 4000BP to 1000BP the climate became warmer, drier and more variable. During this period sea level retreated, forests became more open and the understorey was greatly reduced. Species including Perameles bougainville, Pseudomys bolami, Sminthopsis dolichura, Sminthopsis hirtipes and Thylacinus cynocephalus appeared and/or became dominant. A carbon date associated with a T. cynocephalus tooth suggests an age of 3030+60BP making it the youngest mainland occurrence recorded. Around 1000BP precipitation increased and climate became slightly less variable, resulting in an increase in forest and understorey density. Macrotis lagotis appeared and I. obesulus returned while P. bougainville and many arid zone species retreated. These species changes can be associated with the increase in density of forest and understorey during the period of increased precipitation.