Sedimentological and palynological investigations of Great Songkhla Lakes, east coast of the Malay-Thai Peninsula, Southeast Asia, reveal sedimentary sequences rich in palynomorph assemblages dominated by pollen of mangroves and freshwater swamps. Compared with other regions in Southeast Asia the assemblages are of relatively low diversity. Geochronological data indicate that the Great Songkhla Lakes record one of the earliest mangrove environments in Southeast Asia (8420-8190 cal. yr BP), which are subsequently replaced by a freshwater swamp at 7880-7680 cal. yr BP owing to the decline of marine influence. Sea-level observations from Great Songkhla Lakes and other areas of the Malay-Thai Peninsula reveal an upward trend of Holocene relative sea level from a minimum of − 22 m at 9700-9250 cal. yr BP to a mid-Holocene high stand of 4850-4450 cal. yr BP, which equates to a rise of c. 5.5 mm/yr. The sea-level fall from the high stand is steady at c. − 1.1 mm/yr. Geophysical modelling shows that hydroisostasy contributes a significant spatial variation to the sea-level signal between some site locations (3-4 m during the mid-Holocene), indicating that it is not correct to construct a single relative sea-level history for the Malay-Thai Peninsula.

Although pollen evidence can remain at a crime scene for many years, some pollen species are more susceptible to decay than others. Mature pollen grains of 9 pollen species were placed in nylon gauze bags and buried in 3 types of tropical soil, leaf mold, swamp clay, and sandy soil, in June 2007. Degradation rates and effects of some environmental factors on pollen deterioration were then determined. Observations were made after 2, 4, and 6 months of burial, and the pollen classified into 3 types: identifiable, non-identifiable to species, and absent in the case of complete destruction. Results showed that pollen from different plant species had different rates of deterioration but in all cases pollen deteriorated more slowly in sandy soil. Soil Eh and pH, and infection by fungi seemed to have little influence on pollen preservation. However, pollen preservation of some pollen species was affected by time. It is apparent that complex destructive factors play different roles in different depositional settings. This allowed each area to yield a unique pollen composition. From a forensic point of view, this specific composition becomes part of the evidence that may link a suspect to the precise crime scene.

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