Mamuju is an area of high natural radiation in Indonesia with high natural radiation levels (average 613 nSv h⁻¹). Mamuju is anomalous due to its high average ²³⁸U and ²³²Th concentrations of 22,882 and 33,549 Bq kg⁻¹, respectively, in laterite and rock. High natural radionuclide concentrations of ²³⁸U, ²³²Th, and ⁴⁰K have also been reported in soil samples from several locations in Mamuju, including Botteng, Northern Botteng, Takandeang, Ahu, and Taan. High radiation levels are related to radioactive mineral occurrences in the Adang volcanic complex, comprised of phonolitoid and foiditoid lithologies. According to the International Atomic Energy Agency (IAEA), uranium deposits can be classified into several types, among them a volcanic-related deposits, which include three sub-types: stratabound, structure-bound, and volcano-sedimentary deposits. This study aims to characterize volcanic rock deposit sub-types in the Mamuju area based on uranium radioisotope measurements. The uranium isotopes were measured using a tandem quadrupole inductively coupled plasma mass spectrometer combined with chemical separation by extraction chromatography using UTEVA resin. The analytical results for the ²³⁴U/²³⁸U ratios are used to determine the formation characteristics of minerals in each deposit sub-type based on mineral formation age, post-formation processes, and disturbances that affected the formation processes. Based on geochronological calculations using ²³⁴U/²³⁸U mineralization age, the deposits in the Mamuju area are 0.914–1.11 million years old and are classified as recent mineralization. These data have important implications for tracing uranium source rocks in the Mamuju area and may explain the anomalously high radiation levels in the Mamuju area.

The Mamuju region in West Sulawesi, Indonesia, is a High Background Natural Radiation Area (HBNRA) characterized by a significant enrichment of high field strength elements (HFSEs) and rare earth elements (REEs) within its lateritic deposits. This study investigates the geochemical behavior, mineralogical distribution, and enrichment processes of HFSEs and REEs in lateritic profiles of drill cores and surface samples derived from alkaline volcanic rocks. The mineralogy and geochemical content of HFSEs and REEs in the alkaline bedrocks indicate its potential to become a source of lateritic enrichment. An intense lateritic weathering process leads to the residual accumulation of HFSEs and REEs, particularly in B-horizon soils, where clay minerals and Fe–Al oxides are crucial in element precipitation. Moreover, groundwater redox conditions are a key factor for uranium precipitation in the lateritic profile. The findings provide insight into the potential of lateritic weathering as a natural mechanism for HFSE and REE concentration, contributing to the broader understanding of critical metal resources in Indonesia. These insights have implications for sustainable resource exploration and environmental management in areas with high natural radiation exposure.

Radiometric mapping could play a prominent role in locating the host rock or alteration that leads to gold mineralization. Nevertheless, in low-sulfidation epithermal gold deposits, the radiometric signatures have to be priorly characterized due to their geometry. It is comprised of a small ore vein system within the large alteration zones. The Pongkor gold mine is a low-sulfidation epithermal deposit and was selected for this purpose. The method started with the surface identification of radiometric signatures on altered and unaltered rocks near Pongkor using portable spectrometers. They are followed by the characterization of the underground mining front, which is comprised of different types of veins and host rocks. The results show that the altered rocks were characterized by a high K% and a low eTh/K ratio. Vice versa, the mineralized veins show low radioelement concentrations. Following the characterization of the geometry of alteration zones and mineralized veins, a study of the relationship between radioelements detected by radiometric mapping and gold pathfinder elements was conducted. Gold pathfinders of Mn, Fe, Zn, As, and Pb were selected for correlation studies with the radioelement. The pathfinders and radioelements were more significantly correlated in veins compared to the host rock. Based on this study, radiometric mapping has the potential and benefit of being applied in the exploration of low-sulfidation epithermal gold deposits. An alteration zone could be delineated by K or eTh/K as an anomaly indicator, and the vein bodies could also be delineated using low K or eTh as an anomaly indicator.

Research of the depositional environment using geological mapping, petrography, gamma-ray (GR) log, palynology, and foraminifera fossils of the Bojongmanik Formation has led to the formation of several different conclusions about the transition to the marine environment, which are attractive to revisit. The expected results of this research are to determine the paleoenvironment of the Bojongmanik and Serpong Formations based on elemental geochemistry, the development of paleoenvironment proxies based on portable X-ray fluorescence (pXRF) in fluvial to transitional environments studies, and the contribution of paleoenvironment analysis to GR-log facies interpretation. The research methodology starts with GR-log facies analysis, Pearson’s correlation, paleoenvironment analysis based on elemental affinity and elemental ratio, and comparing the paleoenvironment with GR-log-based facies. The paleoenvironment analysis based on elemental geochemistry resulted in the Bojongmanik Formation in the research area deposited at the tidal point bar, lagoon, and shoreface, while the Serpong Formation was deposited at the fluvial point bar and floodplain. Compared to previous research, the Bojongmanik Formation in the research area could be stratigraphically related to the upper Bojongmanik Formation. Proxies based on elemental geochemical affinities of carbonate-associated, carbonate-productivity, terrigenous-associated elements, and redox-sensitive trace elements show contrast changes between facies. Proxies based on the specific ratio show a detailed paleoenvironment for paleoclimate (Sr/Cu), paleosalinity (Sr/Ba), paleoredox (Cu/Zn), paleo-hydrodynamics and water depth (Zr/Rb and Fe/Mn), sediment provenance (Cr/Zr), and siliciclastic-dominated (Zr + Rb)/Sr. Adding a geochemistry element-based paleoenvironment analysis benefits from a more specific justification for GR-log facies interpretation.