HOLOCENE SEA LEVELS AND PALAEOENVIRONMENTS OF THE MALAY-THAI PENINSULA, SOUTHEAST ASIA

We reveal through sedimentological and palaeontological investigations of Great Songkhla Lakes, east coast of the Malay-Thai Peninsula, Southeast Asia, a sedimentary sequences consisting of very rich palynomorph assemblages that are dominated by pollen of mangroves and freshwater swamps, but compared to other regions in Southeast Asia are of relatively low diversity. Chronological data indicates that the Great Songkhla Lakes have one of the earliest recorded mangrove environments in Southeast Asia (8420 to 8190 cal yrs BP) that are subsequently replaced by a freshwater swamp at 7880 to 7680 cal yrs BP due 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 yrs BP to a mid-Holocene high stand of 4850 - 4450 cal yrs BP, which equates to a rise of c. 5.5 mmyr-1. The sea-level fall from the high stand is steady at c. -1.1 mmyr-1. Geophysical modelling shows that hydro-isostasy 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.