REKONSTRUKSI PALEOKLIMAT DAN PALEOSEANOGRAFI PADA PLEISTOSEN AKHIR – HOLOSEN DI PERAIRAN BARAT SUMATRA

• Main Author: Wiguna, Alwi
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/50648
• Institution: Institut Teknologi Bandung

Paleoclimatic data is used to examine the hypothesis of climate changes causes. Paleoclimatic reconstruction could be determined by analyzing physical and chemical properties of sea sediment and biogenic substances such as foraminifera. The West Sumatra Waters are in the monsoon wind system and influenced by the Indian Ocean Dipole (IOD) climate phenomenon. The research location is in the West Sumatra Waters, which is located between Sumatra Island and Simeulue Island and geographically located at coordinates 03?42' 057’’ N and 095? 37' 005’’ E. The object of this research is a gravity core sediment with sample code EW17-05 which was previously taken by the LIPI Research Team through the Widya Nusantara Expedition in the West Sumatra Waters in 2017. The sample was taken at a depth of 1.176 m below sea level and has a length of 200 cm. This study aims to reconstruct and determine the paleoclimate and paleoceanography in the Late Pleistocene – Holocene in the Western Waters of Sumatra, and to find out its relationship with IOD. The analysis conducted in this study are grain size analysis, geochemical (X-Ray Fluorescence) analysis, and foraminifera analysis. Grain size analysis is performed to determine the statistical parameters of grain size. Geochemical analysis ia carried out to determine the chemical elements contained in the sample and be used as a proxy for sediment input and weathering intensity which is considered to represent the dominance of IOD. Foraminifera analysis is carried out to determine the species and abundance of foraminifera that is used for Modern Analogue Technique (MAT) analysis to determine Sea Surface Temperature and biozonation analysis by conducting constrained clustering. The age limit between Pleistocene and Holocene is marked by the First Appearance Datum (FAD) of Bolliella Adamsi at a depth of 144 cm from 1.176 m below sea level. Based on the results of paleoclimate and paleoceanography reconstructions, there are 7 climate periods and there are global climate phenomena such as Younger Dryas, Tropical Cooling, Mid Holocene Peak, and 4,2 K event. The climate phenomenon of IOD has a relationship with the dynamics of paleoclimate and paleoceanography in the West Sumatra Waters. Positive IOD dominates the cold climate which is characterized by the decreased rainfall and negative IOD dominates the warm climate which is characterized by the increased rainfall.