Chemical signatures of palaeotsunamis: A forgotten proxy?

A range of diagnostic criteria are required to help identify palaeotsunami deposits. Although chemical signatures have long been used as indicators of palaeosalinity in sedimentary sequences, their use in the studies of palaeotsunami deposits is rarely applied and is yet to be widely recognised. The chemical composition of interstitial water in coastal ponds and sedimentary sequences in coastal marshes and lagoons has been used successfully as an indicator of tsunami inundation. Chemical signatures can also provide clues about the landward limit of runup of a tsunami, beyond the area of sediment deposition. Like most palaeotsunami proxies however, the preservation of chemical signatures varies with environmental conditions.