Figure 1 shows a stratigraphic section of an excavation site QML796, with undisturbed stratigraphy that represents ephemeral fluvial channel and overbank deposits in a small, restricted catchment on the Darling Downs, southeastern Queensland, Australia. During excavation, bivalve shells were collected as part of research into the implication for radiocarbon dating in cryptic meteoric diagenesis in freshwater bivalves.