The distribution and petrography characteristics of material eruption in the south of Rawa Danau, Banten Province

Abstract

Banten is an area that has geological uniqueness, particularly in Rawa Danau on the North side. The research area is a young volcanic complex surrounded by several mountains such as Mount Aseupan, Parakasak, and Karang in Serang district in Banten province. The Rawa Danau consists of swamp and lake, which is located inside an estimated Pliocene-Pleistocene caldera as the result of the ancient volcanic eruption. Based on the previous study the lithology of the lake was fine-grained fluvial sediment and swamp deposit with volcanic material. The aim of this study is to reconstruct the behaviour of the eruption in the research area and to know the area affected by the eruption using petrography analysis. The research area is dominated by pyroclastic such as breccia, tuff, and andesite in the form of lava flow and basalt that originate from M. Parakasak, M. Aseupan, and M. Karang. The mineral contents of the igneous rocks are plagioclase, pyroxene, and opaque with the microlith plagioclase as the groundmass. The degree of plagioclase extinction angle was used to differentiate between andesite rock and basalt rock. Andesite rock has more acidic plagioclase than basalt rock. The texture of andesite rock is trachytic implied that the geometry is a lava flow. The basalt rock has porphyritic texture and becomes the part of the caldera wall of Mount Parakasak.