Analysis geoelectrical resistivity and XRF geochemistry to characterize limestone distribution and quality in a carbonate–volcanic terrain of Cimanggu, Pandeglang, Banten, Indonesia

Limestone quality in carbonate and volcanic settings is strongly influenced by lithological variability, non carbonate sediment input, diagenetic modification, and proximity to igneous bodies. This study aims to evaluate subsurface limestone occurrence, lithological characteristics, and geochemical quality in the Cimanggu area, Pandeglang, Banten, Indonesia, through combined application of geoelectrical resistivity data and X-ray fluorescence (XRF) analysis.
Geoelectrical investigation was conducted using 15 measurement datasets, consisting of 11 vertical electrical sounding points with Schlumberger configuration and four lateral profiles with Wenner configuration. Resistivity data were processed using IP2Win and Progress software to generate one dimensional models and correlated two dimensional subsurface sections. XRF analysis was performed on ten representative rock samples to determine major oxide compositions, particularly CaO, SiO₂, MgO, Al₂O₃, and Fe₂O₃, as indicators of limestone purity and impurity contribution.
Results identify five principal subsurface units: soil cover, claystone, low grade limestone, high grade limestone, and andesitic to basaltic igneous rocks. High grade limestone is mainly concentrated in the central part of the study area, particularly around GL 2, GL 3, GL 5, and GL 9, where carbonate intervals reach approximately 40–50 m in thickness. This limestone is chemically characterized by CaO >52%, SiO₂ <2.5%, MgO <0.5%, Al₂O₃ <1.1%, and Fe₂O₃ <1%. In contrast, low grade limestone occurs mainly in the western sector and near intrusive zones, showing CaO <52% with elevated impurity oxides.