Parameters Controlling the Uranium Mineralization in the Ingall Sector, Tim Mersoï Basin (Northern Niger)

Abstract

This study focuses on highlighting and controlling of uranium mineralization in the Ingall area (Northern Niger). The study sector is an integral part of the Tim Mersoï basin located to the northern part of the Iullemenden syneclise. Located on the western edge of the Aïr Massif, this basin, known for its uranium mineralizations, has a sedimentary filling ranging from Devonian to Lower Cretaceous. All the sedimentary formations of this basin end in a bevel on the western edge of the Aïr Massif. To carry out this study, the radiometric airborne geophysics technique was first deployed to highlight surface uranium anomalies. These were then verified by ground radiometry technique. The mapping work then identified the major geological structures that controlled the emplacement and distribution of the mineralization. Drilling and logging techniques were used to determine the mineralization host formations, the Assaouas and Tchirezrine-2. The results of this work show two envelopes of surface uranium anomalies at the 100 cps to 200 cps cut-off in the centre of the study area. These anomalies have a vertical extension to a maximum depth of 240 m, where highest values are located. This uranium mineralization occurs as lenticular ore bodies in the Ingall sector. Tectonic structures (normal faults), palaeogeography and chemical elements (reducing elements) are the main factors controlling the concentration and distribution of this mineralization. This study shows that this area, underestimated for decades, is potentially rich in uranium mineralization.