The Potential of Sukadana Basalt Province as a New Geothermal Resources in The Back Arc of Sumatra

Abstract

Geothermal resources are currently obtained from areas within volcanic arcs, such as the Pertamina Ulu Belu and Supreme Energy Rajabasa Geothermal Fields. However, this understanding may change in the future, as the Quaternary Sukadana Basalt Province (SBP), located in the back arc, is believed to have potential as a future geothermal energy resource. This research aims to explore the various factors that contribute to the high heat flow in the SBP region and generate a new perspective on geothermal energy particularly in the Lampung province. The methods used integrate previous research findings, such as heat flow data, regional tectonics, and geological structures, with new petrography-whole rock geochemistry. The whole rock geochemistry was determined using X-Ray Fluorescence (XRF), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The SBP was formed by the Paleogene northwest-southeast striking fault and influenced by the Quaternary northeast-southwest striking fault, which may serve as conduits for hydrothermal fluid in addition to their vesicular structures. Geochemical analysis suggests the presence of both mantle plume and subduction-related processes. The magmatism linked to subduction-plume tectonic mechanisms and the thinning of the crust due to pull-apart motion caused by the movement of two large faults (Sumatra Fault Zone and Bangka Shear) can increase regional heat flow to 100±10 mW/m2. As a result, the SBP has significant potential as a source of geothermal energy for electricity generation in the future.