PALEOENVIRONMENT OF MALAWA FORMATION AND PALEOCLIMATE RECONSTRUCTION OF BARRU AREA, SOUTH SULAWESI BASED ON PALYNOLOGY PROXY

• Main Author: Zulfiah
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47287
• Institution: Institut Teknologi Bandung

mass extinctions and long-lasting impacts, namely Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum (ETM). The condition of vegetation in the maximum thermal events has been widely studied in mid and highlatitude regions, but the characteristics of vegetation at that time in the tropics, such as in Indonesia, are still unclear. Study area was conducted in Padanglampe traverse, Tanete Riaja area, Barru Regency, located in low latitude area, 040 30’ 25.26” LS dan 1190 41’ 43.43” BT. The study was carried out on sediment deposits from the Eocene Malawa Formation and is composed of relatively fine to medium-grained sediment and intercalated coal. Rock sampling were systematically carried out at any distance of 25 cm from the measurement of the stratigraphic cross-section. The previous study identified the depositional environment of Malawa Formation based on macrofossil, but the use of palynomorphs has not been carried out in detail and Paleogene climate study using palynomorphs is still rare in Indonesia. This study using palynology proxy as the main approach to know paleoenvironment and paleoclimate changes in the research area. Determination of depositional environment uses the Palynomorph Marine Index (PMI) and the palynomorph abundance zonation methods, while the paleoclimate analysis uses the Coexistence Approach-Nearest Living Relative (CoA-NLR) and Individual Approach (IA) methods. The results of biostratigraphic analysis of 36 samples found marker fossils that consists of Proxapertites operculatus, Palmaepollenites kutchensis, Florschuetzia trilobata, Retistephanocolpites williamsi, Cicatricosisporites eocenicus, Polygalacidites clarus, Spinizonocolpites echinatus, and Beaupreadites matsukae. Based on this analysis, Padanglampe traverse is in the Proxapertites operculatus Zone which is deposited in Middle Eocene - Late Eocene. PMI analysis result shows the transitional environment with the fluctuating changes from freshwater/terrestrial to the marine environment influenced by tidal, whereas the palynomorph abundance analysis shows the depositional environment of Padanglampe Traverse is deltaic system. Based on CoA-NRL analysis, the study area has a mean annual temperature (MAT) of 15.60 – 25.50C and the mean annual precipitation (MAP) of 175-2750 mm. The result of the MAT and MAP values plotted on the biomass diagram shows that the local climate is the tropical seasonal forest and the IA analysis shows that the paleoclimate of the study area is warm and wet climate. Globally, study area was still influenced by Eocene Thermal Maximum (ETM) in 10.5 – 6.5 m depth, but in 6.5 – 0 m depth occurs the cooling phase which is marked by the presence of Podocarpus sp. and Restionidites punctulosis. Based on the results of this study and previous studies in Java and Sulawesi, the climate that develops in low latitudes, such as Indonesia during the Eocene, is a tropical climate with warm and humid conditions.