Identification characteristics of volcanic deposits in Cimarga, Southeast Banten

Volcanic eruption(s) in the past occurred around rawa danau volcanic complex is marked by the presence of a caldera and widespread volcanic deposits in the Banten Province as Tuff Banten. This study aims to determine the possible mechanism of the eruption based on volcanic deposits. Moreover, this study will also present the prolonged research process to understand the dynamics of volcanic deposits in Banten. Field study and sampling of volcanic deposits were completed followed by thorough petrographic analysis. There are three outcrops all with different characteristics. There are 6 layers in outcrop 1. Out of six layers, layer 1 (P1) until layer 5 (P5) appear similar, consisting of pumice rich (as fragment) and lapilli layer, while layer 6 (P6) consists of massive ash. In outcrop 2, there are 5 layers, which show cross and parallel laminations in each layer. Outcrop 3 contains 3 layers with the top and bottom layers consisting of lithic and pumice lapilli that are medium in size. Based on grain size from each outcrop, grain size from outcrop 1 until outcrop 2 progress into finer grains. From these characteristics outcrops 1 indicated flow deposits, outcrop 2 indicated surge deposits, and outcrop 3 indicated flow deposits. Therefore the facies from all three outcrops lean towards medial to distal with outcrop 3 as a distal facies.