MULTIPROXY ANALYSIS OF PALEOCLIMATIC CONDITIONS AND PALEOCEANOGRAPHY IN THE LATE PLEISTOCENE–HOLOCENE IN NORTH PAPUA WATERS, PACIFIC OCEAN

• Main Author: Damanik, Adrianus
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/40424
• Institution: Institut Teknologi Bandung

Paleoclimate analyses and paleoceanography in North Papua Waters was chosen in the Nusa Manggala Expedition 2018 because it is located in a strategic position. The North Papua Waters is one of the entrances for the ITF (Indonesian Through Flow) and also affected by ENSO (El Niño Southern Oscillation). This study aims to reconstruct and understand the influence of ITF and ENSO, as well as to find the relationship between ITF and ENSO in the Late Pleistocene-Holocene. The analyses was carried out using a 246 cm core gravity sample. The sample, with code OS-07, were taken from a 4327 m depth in the North Papua Waters, Pacific Ocean, with coordinates 01?15'161 N and 132? 23'831 E. Paleoclimate and paleo-oceanography analyses were performed using multiproxy: 2 radiocarbon dating, 246 grainsize and XRF (X-Ray Flurescence) analysis, and 47 LOI (loss on ignition) and 47 foraminifera analysis. Dating analysis was carried out with 14C radiocarbon dating on three foraminifera species, Neoglobquadrina spp., Globorotalia spp., Pulleniatina spp., at the bottom and the center of the sample. The grainsize analysis was carried out to find the statistical parameters such as mean, median, sorting, skewness, kurtosis, and the percentage of grain size >63 microns, for sediment input anlysis. XRF analysis was also carried out to determine the content of chemical elements to understand the weathering proccess and also rainfall. These are considered to represent the dominance of La Niña and El Niño. Loss on ignition analysis was carried out to determine the carbonate and carbon contents in the samples which can be used to interpret the temperature and relative humidity. Analysis of the foraminifera distribution was carried out quantitatively to determine the distribution of foraminifera and the ecological character of the study area. Result of the constrained cluster analysis, 17 cluster, showed fluctuations in climate conditions and oceanography of the study area.Sea surface temperature was obtained with the MAT (Modern Analogue Techinque) method. The results of paleoclimate and paleo-oceanographic reconstructions showed differences in temperature, climatic conditions, ENSO dominance, and ITF intensity, between the Pleistocene and the Holocene. The temperature analysis indicates that compared to the Holocene temperature, there were 1.33oC and 0.82oC cooler conditions in February and August during the Pleistocene, which was also drier compared to the warm and humid Holocene. In the Pleistocene La Niña and El Niño frequencies were seen to be relatively similar, whereas in the Holocene there was an increase in ENSO intensity / El Niño dominance. The ITF intensity was higher in the Pleistocene compared to the Holocene. Paleoclimate and paleoceanographic reconstruct 10 periods of climate, namely Period 1, consisting of clusters 1A-1C (> 17.602BP; end of Last Glacial Maximum / LGM), Period 2, consisting of cluster 1D (17.602-16,229 BP; Oldest Dryas), Period 3, consisting of 1E-1G clusters (16,229-13,509 BP; Bølling Interstadial), Period 4, consisting of 1H clusters (13,509–11,980 BP; Older Dryas), Period 5, consisting of cluster 1I (11,980 - 10,960 BP; Allerød Interstadial then Younger Dryas), Period 6, consisting of clusters 2, 3, and 4A (10,960 - 7,902 BP; Preboreal-Boreal), Period 7, consisting of clusters 4A and 4B (7,902–4,333 BP; 8.2K and Tropical Cooling ), Period 8, consists of cluster 5 (4,333-3,824 BP; Holocene Thermal Maximum / HTM), Period 9, consisting of cluster 6A (3,824-765 BP; Subboreal then Medieval Warm / MW), Period 10, consisting of cluster 6B (765 BP; Little Ice Age / LIA). The results of paleoclimatology and paleo-oceanographic analyses show that the ITF intensity is related to the intensity of ENSO. Both affect climate dynamics and oceanography in the study area. In Pleistocene, ITF flows tend to be higher indicating the frequencies of El Niño and La Niña are almost the similar, and in the Holocene, with lower ITF intensity, are associated with increased intensity of ENSO.