ANALISIS PERUBAHAN SUHU PERMUKAAN LAUT DAN IDENTIFIKASI UPWELLINGBERDASARKAN FORAMINIFERA PLANKTONIK SEJAK AKHIR LAST GLACIAL MAXIMUMDI WILAYAH PERAIRAN PULAU SIMEULUE, ACEH

Analysis of climate change and oceanography in Simeulue waters, Aceh since the Late Pleistocene-Holocene were researched because this study area located in the tropical Indian Ocean which plays a role in the dynamics of the global climate change. The study area is on the eastern Indian Ocean which is affected by the variability of the atmosphere and oceans throughout the year. This study aims to determine changes in sea surface temperature (SST) andtoidentify upwelling using foraminifera proxy. A marine sediment core EW17-08 along 217 cm (94° 46’ 43” longitude and 2° 29’ 47” latitude) was retrieved fromthe western side of Simeulue Island, Aceh, waterdepth of 2.811 m. Based on AMS radiocarbon dating, the age of sediment core EW17-08 is 21.300 BP (Late Pleistocene). Based on SST analysis using Modern Analogue Technique (MAT) method, the averageSST in the Late Pleistocene and during Holocene was 27.78oC and 28.15oC, respectively. Based on SST and tropical-subtropical foraminifera, there are 4 (four) periods of climate variation since ~21,300 BP. The difference of SST in the Late Pleistocene-Holocene in the study area is not very significant, but there have been several abrupt decreased of SST which may be related to climate change events on earth that occurred since the Last Glacial Maximum (LGM) such asdeglaciation, Oldest Dryas, Bølling Interstadial, Older Dryas, Allerød Interstadial, Younger Dryas, Preboreal-Boreal, 8.2k event, Holocene Thermal Maximum, 4.2k event, Subboreal, and Little Ice Age. The intensity of upwelling in the study area showed an increase in the Late Pleistocene at a depth of 100-160 cm based on abundance of Globigerina bulloidesand the others. The upwelling intensity is estimated to be influenced by the increasing intensity of the southeast monsoon.