Textural and microfossil analyses plus radiocarbon dating from the tidal marsh Cha-am and Kui Buri Swale in Thailand

The primary diagnostic for recognizing prehistoric typhoon-deposited sand layers in the geologic record are sharp upper and lower contacts between coarser-grained transported sand layers and finer-grained in-situ sediments. In this first paleotempestology study in Thailand, cores from two low-energy settings on the Gulf of Thailand coast - a coastal marsh near Cha-am and beach ridge plain swales near Kui Buri - reveal geologic evidence of up to 19 typhoon strikes within the last 8000 years.

The sand layers have sharp upper and lower contacts with enclosing finer sediments. Some sand layers also contain other evidence of a sudden powerful landward-directed surge of ocean water, including gravel-sized clasts, offshore foraminifera, abundant shell fragments, plant debris and mud rip-up clasts. Sand layers record eleven typhoon strikes at Cha-am, ranging in age from AD 1952 to 7575 cal. yr.