PALEOCLIMATE AND PALEOCEANOGRAPHY ANALYSIS IN PLEISTOCENE – HOLOCENE IN WEST SUMATRA WATERS

• Main Author: Puspita Ningrum, Anindyta
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/43711
• Institution: Institut Teknologi Bandung

The earth has been experiencing various climate changes and the changes almost always occur in each earth's period so paleoclimatology has an important role to understand the past earth's climate. In addition, the paleoclimate information can also be used as a reference to predict the future earth's climates because each climate variation shows a repetition pattern in each specific time span. In this study, paleoclimate and paleoceanography analyses were conducted using sediment drill core ST 06 at EW 17-06 station which is geographically located at coordinates 03?18'339'' Northern Latitude and 095?20'932 '' Eastern Longitude. The sample was taken in West Sumatra Waters from -1.144 meters below sea level by geology team from LIPI in 2017 on Widya Nusantara Expedition. West Sumatra Waters are the areas which are influenced by local climatological phenomena, namely IOD (Indian Ocean Dipole). This study aims to reconstruct and understand influence of IOD at the study area. Paleoclimate and paleoceanography analyses were performed using 210 samples of grain size analysis, 210 samples of X-Ray Fluorescence (XRF) analysis, 52 samples of Loss on Ignition (LOI) analysis and 27 samples of foraminifera collection. Grain size analysis was performed to determine the statistical parameters grain size such as mean, median, sorting, skewness and kurtosis. XRF analysis was carried out to determine the content of chemical elements as a proxy for sediment input and weathering which is considered to represent the dominance of IOD+ and IOD- in the study area. LOI analysis was carried out to determine the carbonate and organic carbon content in the sample which can show the temperature and relative humidity. Foraminifera collection analysis was carried out quantitatively to determine the distribution of foraminifera and ecological characteristic of the study area. The age limit between the Pleistocene and the Holocene is on a depth of 162 cm from 1.144 meters below sea level, marked by the First Appearance Datum (FAD) from Bolliela adamsi species. The reconstruction of Paleoclimate and paleo-oceanography in the study area resulted in 6 Holocene climate periods, known as HTC (Holocene Tropical Climate), that is HTC 6, HTC 5, HTC 4, HTC 3, HTC 2 and HTC 1. In addition, several global climate events were also recorded, such as Younger Dryas, 8.5 ka Event, Medival Warm Period and Little Ice Age. The phenomena of Regional climate in West Sumatra territorial Waters such as IOD contribute to fluctuations in climatic conditions and sea water in the study area. The cold climate is dominated by the intensity of IOD+ which is characterized by the decreased rainfall while the warm climate is dominated by the intensity of IOD- which is characterized by the increased rainfall.