Study of Eruption Mechanism Pyroclastic Deposit of Banten Tuff (Qpvb) in Pancanegara and its surrounding Using Grainsize Distribution and Componentry Analysis

Abstract

Banten Tuff (Qpvb) is pyroclastic deposit that is very significant in western Java Island. The importance of this deposit is caused by spreading and covering most of Banten region. In the middle of Banten Tuff, there is a caldera that has rectangular shape and the large area 13.7 km x 6.5 km. The research in this area has not studied yet that explain the characteristics of pyroclastics deposit in detail, therefore it’s hard to tell how the eruption process and mechanism that happened based on the deposit. This study become solution of a puzzle about process, mechanism, history, and episode of eruption. The research methods are using qualitative and quantitative analysis such as grain-size distribution and componentry. The study has succeed obtaining more than ten outcrops that described in detail. Description of outcrops resulted tephra-stratigraphy correlation in four facies unit. These four facies categorized into three eruption phases. Eruption phases are arranged into a story which is useful for determining historical and episode eruption in Pancanegara and its surrounding.