Uranium deposit reflection from radon-thoron in Melawi Basin, West Kalimantan

• Main Authors: Indrastomo, Frederikus Dian, Sukadana, I. Gde, Adimedha, Tyto Baskara, Cakrabuana, Wira, Fauzi, Rachman, Syaeful, Heri, Ciputra, Roni Cahya, Rachael, Yoshi
• Format: Conference Proceeding
• Language: English
• Subjects: Alluvial deposits; Alluvium; Geological mapping; Geological surveys; Physical properties; Radon; Sandstone; Sedimentary rocks; Soils; Thorium; Uranium
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0192880

Tebidah Formation is a 20,000 km wide and 1,000 m thick sedimentary rock in Melawi Basin. The formation in the Ella Hilir area shows the possibility of becoming a uranium deposit host rock based on the environment and physical properties. Geological mapping and radiometric surveys were carried out in the area to identify the uranium contents on the surface. Radon-thoron gas measurement in soil was carried out to find the reflection of uranium content in the subsurface. The geology of the research area is composed of sandstone, claystone, sandy-conglomerate, and alluvium units. Radiometric surveys show the presence of uranium and thorium anomalous zones to the north and slightly south of the area. Measurement of soil radon gas ranges from 11.52 – 47650.63 Bq/m3. Radon anomalies area is determined by concentration 7875.45 – 47650.63 Bq/m3 or 50.13 – 303 CPM and a radon-thoron ratio of 1.24 to 358.27. Radon strong anomaly distribution showed several anomalous zones trending northwest-southeast, which correlated with normal fault structures and sag pond morphology. The reflection of uranium deposit potential zones is in areas with high radon content and strong anomaly classification. A further study of the potential zones should be proposed to characterize subsurface lithologies.