Géoinformatique et géostatistique : un aperçu

Using of Local Singularity Analysis for Determining of Radioactive Zones based on Airborne Geophysical Data, NW Iran

Seyed Afshin Majidi, Maryam Sadat Majidi, Saeid Soltani Mohammadi, Ehsan Ashuri, Soheila Sadat Majidi

The Khoja syncline is located about the middle of the SarabTabriz-Salmas basin in NW of Iran and regarded as one of the most promising areas to explore for radioactive elements. The main purpose of this study is to utilize the fractal and multifractal geometry measurements, including the Local Singularity Analysis for data interpretation and delineation of radioactive anomalous zones as a mineral exploration tool in the sedimentary rock units of the Khoja syncline. To delineate uranium concentrations detected areas (high radioactivity zones) 5934 points of uranium gamma-ray spectrometry airborne geophysics were collected and saved as data. According to Local Singularity Analysis, uranium accumulation in the Khoja syncline follows a multiracial model in shape. Highly elevated radioactivity is detected inside the NW of the syncline in the limestone lithological unit. Based on the direct correlation between uranium high value and Ca, Mg, P, Sr, as and V, the limestone unit concentrated metals as a geochemical trap. The mineralization zone reflecting secondary uranium mineralization in this part of syncline with ≈ 74 to 800 ppm uranium consisted of 380 to 3500 counts per second radioactivity. The calculation function of the concerning mass and grade resolution, Local Singularity Analysis method yielded relatively efficient results referring to strong and weak uranium concentration as high radioactive zones.