Salinity Stratification and its Effects on the Malay Basin Biofacies Assemblages

Salinity stratification usually occurs when tidal currents and waves are not strong enough to mix the water column (e.g. in wave-dominated estuary). Such situation can lead to an anoxic condition because bottom waters can become isolated from dissolved oxygen (source: www.ozcoasts.org.au). Stratified salinity is a feature of partially enclosed seas and paralic environment (Debenay et al., 2000). In a stratified water column, the exchange of water and nutrients between layers is restricted, therefore there can be quite different water quality between the stratified layers; which has direct effect on the biofacies assemblages and distribution. (Debenay and Guillou, 2002). This biofacies event provides a possible explanation that for much of the Miocene, the Malay Basin might have been an enclosed sea, with a limited marine connection at the south to let saline water in.