STUDY OF NANNOFOSSIL IN QUARTERNARY PERIOD AT NORTH OCEAN OF PAPUA AND ITS RELATION WITH PALEOCLIMATE

• Main Author: Krismonadi, Patrio
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/48537
• Institution: Institut Teknologi Bandung

-Nannofossils are a specific component of the ocean. The distribution of this organisms can represent the ecological conditions this organisms live. The study was conducted in the north ocean of Papua on the West Caroline Plate, an area in the open sea, free from underwater fan sedimentation so it is suitable for biogenic sediment research. Research on biogenic sediments especially nanofossils on the West Caroline Plate has been conducted by the International Ocean Drilling Program (IODP) site 1490 in 2016 which shows a good level of preservation so that the data used in the study are reliable. However, research carried out specifically for nannofossil proxies regarding the abundance of taxa when the Holocene has not conducted yet. Meanwhile, this study aims to determine the characteristics of OS-07 gravity core sediments and the abundance of nanofossils in samples as well as their relationship with paleoclimates. This research is part of the 2018 LIPI Nusa Manggala Expedition using the Baruna Jaya VIII Research Ship. Samples were taken using a gravity core located in the northern waters of Papua at a depth of 4327 meters below sea level with a core length of 246 cm. The methods that used in this research were nannofossil analysis at 8 cm interval (8 - 72 cm, 96 - 240 cm) to determine the pattern of nannofossil’s abundance, and detailed at 4 cm interval {0-8 cm (to identify of Little Ice Age Period), 72-96 cm ( to identify Holocene and Plistocene boundary)}, and grain size and X-ray fluorescence anylisis conducted at 1 cm interval (246 pieces), the two analysis conducted to determine sedimentological characteristics and chemical content of the elements. Based on nanofossil analysis, it was found that Emiliania huxleyii and Pseudoemiliania lacunosa species are index fossils for Holocene and Pleistocene boundary , with support data from dendogram constrained clustering results, and absolute age dating. In addition, we get a record of past climate which is divided into 10 depths. Grainsize analysis can characterize core OS 07 samples which are divided into 11 facies based on the mean, sorting, skewness, kurtosis, and sand mixture, which is generally coarsening downward. Based on the results of the XRF analysis obtained characterization of the correlating elements namely Fe, Rb, Sr, and Ca. From these three analyzes a deposition mechanism was obtained at each of the Holocene and Plistocene periods. In addition, the relationship between grain size and abundance of nanofossils is obtained, when the grain is finer, the more abundant nanofossils are obtained. While between the elements contained and nanofossils conduct a relationship that the pattern of sediment input and weathering intensity is directly proportional to the abundance of fossil rework and inversely proportional to the abundance of nanofossils.