IDENTIFICATION OF THE CHARACTERISTICS SEDIMENTOLOGY, GEOCHEMICAL AND FORAMINIFERA OF PALEOTSUNAMI DEPOSIT IN TABANAN, BALI
Subduction zone in Indonesia can be a major reason for underwater earthquake that can cause tsunami. Tsunami imprints can be learned by sedimentological and geomorphological aspect. Bali island is one of the region which located in front of subduction zone between Eurasian plate and Indo-Australian...
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| Format: | Final Project |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/40114 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Subduction zone in Indonesia can be a major reason for underwater earthquake that can cause tsunami. Tsunami imprints can be learned by sedimentological and geomorphological aspect. Bali island is one of the region which located in front of subduction zone between Eurasian plate and Indo-Australian plate. Coastal environment in South Bali region could be the potential location to preserve tsunami deposit. The research is using sample L-02 that was carried out by taking 170 cm depth sediment sample in the field. Identification and characterization of paleotsunami deposit is based on laboratory analysis which is include grain size analysis, XRF analysis, LoI analysis and foraminifera analysis.
The result of this research indicates one layer of paleotsunami deposit on interval depth at 148 cm -170 cm and has total thickness of 22 cm. Based on grain size analysis, the sample has grain size range within fine sand – very fine sand, poorly sorted - very poorly sorted, very fine skewed, kurtosis’s type platykurtic - very leptokurtic and bimodal frequency distribution curves. XRF analysis shows that paleotsunami layer has the highest value of Ca, K and Sr; lowest value of Fe, Mn, V and Ti compared to another layer (non candidate layer). LoI analysis shows a decrease pattern of organic material matter and increase pattern of carbonate material percentage in this layer. Both of the results indicates that the source of deposit is came from marine sediment. The abundance of foraminifera in this layer is dominated by benthic foraminifera which lived in inner neritic - outer neritic environment. Benthic foraminifera that has been found is Rotalia beccarii Linnaeus, Cibicidina walli, Robulus sp. and Pyrgo subsphaerica.
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