Petrogenesis Of Sadakeling - Karaha Volcanic Complex, Tasikmalaya, West Java, Indonesia: Argoland Contamination Azrie Ezziat Putera Muhammad (a*), Mirzam Abdurrachman (a), Mochammad Nugraha Kartadinata (b), Wilfridus FS Banggur (c)
a) Program Studi Teknik Geologi, Fakultas Ilmu dan Teknologi Kebumian, Institut Teknologi Bandung (ITB), Jl. Ganesha No.10, Bandung, Jawa Barat, Indonesia.
*azriezziat20[at]gmail.com
b) Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG), Jalan Diponegoro 57, bandung 40122, Indonesia.
c) Pusat Penelitian Bencana Geologi, Jalan Sangkuriang, Bandung 40135, Indonesia
Abstract
The Sadakeling - Karaha Volcano Complex is part of a Tertiary Magmatic Arc in West Java enclosed with several active volcanoes. Based on the tectonics, this area can be a continuous fragment of the Australian Continent Argoland, which controls the magmatism process. This study aims to determine the magma series, tectonic setting, and the continuity of Argoland contamination using petrogenesis study. The type of data for this study uses nine primary data from geochemical content (major, minor, and trace elements) using XRF analysis. The geochemical studies reveal that the Sadakeling Karaha Volcanic Complex points to the insignificant content in total alkali (3,59 - 4,85 wt.%), yet with positive correlations with increasing SiO2 content (52,48 - 61,8 wt.%). The value range can be categorized into basaltic-andesite with sub-alkaline magma series characteristics, and magma alkalinity was identified as a medium-K series group. Other than that, there is a slight enrichment in FeO compounds, but the trend shifts towards alkaline, representing the tholeiitic magma series. Based on a triangular and bivariate diagram from trace and minor elements, Sadakeling-Karaha Volcanic Complex is categorized as Volcanic Arc Basalt. Due to the strong influence of continental crust from major elements and the bivariate diagram between Zr and Zr/Y, supported by the spider-diagram pattern, this area belongs to the active continental margin. The detailed explanation about the magma source allegedly originates from the contamination between the Sundaland crust in the north and Gondwana in the south. The part of Gondwana or Argoland presence influences is strengthened with an identical Trace element content (Sr and Nd) with the SE Australian Granite.
