PALYNOFACIES SIGNALS OF NEUTRAL AND ACID HYPERSALINE LAKE CORES SOUTH OF NORSEMAN, WESTERN AUSTRALIA

The Yilgarn Craton in Western Australia hosts hundreds of shallow ephemeral hypersaline lakes, majority of which have acid to neutral pH values. A palynofacies study of three cores from two acid lakes (Prado Lake PL1-09 and PL2-09 and Twin Lake West TLW-1) and one core from neutral Gastropod Lake (GLE1-09) south of Norseman revealed an abundance of dispersed organic matter in the sediments. Statistical analyses of these organic components indicate subtle differences in their distribution within each lake and between the lakes. Although abundant organic components, which are mainly phytoclasts (comminuted, structured) and amorphous organic matter, are the most statistically important, minor components such as salt-tolerant algae (Dunaliella?) and opaques also played a role in grouping palynofacies assemblages. The apparent absence of algae in the most recent sediments in Gastropod Lake may be related to predation by the gastropod Coxiella, suggesting that the lake has become more neutral with time. Palynofacies assemblages also appear to reflect heavy influence from nearby vegetation in addition to some reworking.