The Holocene Development of the Larut Matang Mangrove Forest Area and Its Associated Coastal Sedimentary Succession

This study investigates the impact of Holocene sea level change on the development of the Larut Matang Mangrove Forest area and its associate coastal sedimentary succession. Boreholes data from five sites within this study area were analyzed to correlate the sedimentary sequences corresponding to the fluctuations in the sea levels. Three different sedimentary units were identified based on their lithology, fossil content and stratigraphic association; these units can be matched to the Simpang Formation (Pleistocene), Gula Formation (Holocene), and Beruas Formation (Holocene).
Interval I (Simpang Formation), a terrestrial deposits comprising of clay, sand and gravel, is interpreted to have been deposited by fluvial processes during the Pleistocene, possibly during the LGM (Last Glacial Maximum – 18,000 – 15,000 years ago). Interval II (Gula Formation) represents Holocene marine which mostly consists of clay, sand, gravel and some peat. This formation overlies the Simpang Formation, and it is interpreted as a transgression unit correlatable to the sea-level transgression and highstand from the sea-level curve estimated at 9,000 years ago. Interval III (Beruas Formation) is predominantly clay, silt and sand deposited by fluvial process interpreted to have been deposited due to the drop of sea level around 3,500 – 1,000 years ago.
Keywords – Larut Matang Mangrove Forest, Sea level changes, Holocene.