Integrated Radiometric Mapping using Field Based and Remote Sensing Techniques for Uranium and Thorium Exploration at Mamuju Region, West Sulawesi, Indonesia

Mamuju Region in West Sulawesi, Indonesia is a “green”
field area of uranium/thorium in Indonesia. High
radiometric concentrations were located in Adang Volcanic
Rocks. This formation is grouped as basaltic to
intermediate rock and composed by lava, pyroclastic rocks,
and tuff. Regional field radiometric mapping, including
radiation dose rates, potassium, uranium, and thorium
contents of soil and rock was conducted to identify the
existence of radioactive minerals and prospect zones. Some
radiometric anomalies are detected and probably related to
hydrothermal alteration, leaching, and precipitation
processes. Uranium anomaly (97,261 ppm) located in
Mamuju River upstream, Botteng, Takandeang and Ahu
area. The anomaly related to uranium leaching and
precipitation processes in leucite basalt lava. Thorium
anomaly (369,461 ppm) located in Pangasaan, Takandeang,
Ahu, and Taan area. To expand this radiometric mapping,
we characterized the reflectance of Landsat-8 imagery
based on field measurement data. Based on circular
structures identification, uranium/thorium anomaly are
related to the existence of volcano vents on Adang
Volcanic. Based on band rationing, high uranium contents
distributed in the area with less ferromagnesian mineral,
while thorium did not affected. These field based and
remote sensing characterization results could be used as
preliminary parameters to identify wide and detail
prospects.