Investigation of alterations and lineaments in Rashid-Abad mineral area (N Zanjan, NW Iran), Using integration of Remote Sensing and Aeromagnetic data

In this research, remote sensing and aeromagnetic data sets were integrated to investigate structural features and alteration zones of Rashid-Abad mining area. This area is located approximately 45 km north of Zanjan, in the Alborz (western)-Azerbijan zone, NW Iran. For this reason, two main lineaments with the E-W and NW-SE trends were detected using a sun-angle filter of OLI data and, analytic signal (AS) and first-order vertical derivative (FVD) techniques of aeromagnetic data. The other lineaments with other trends in the area are controlled by the same two major lineaments. In order to identify alterations, the methods of band ratio (BR) in ETM+ and OLI, false-color composite (FCC), relative absorption band depth (RBD), and spectral angle mapper (SAM) in ASTER image processing were used in the study area. The results showed the presence of iron oxide, argillic, phyllic, propylitic, and silicic alterations. Also, the area’s aeromagnetic response to different alteration regions was investigated by matching aeromagnetic anomalies with alteration zones. In addition, it was concluded that, iron oxide alterations with negative magnetic anomalies, phyllic alterations with moderate positive magnetic anomalies, and also argillic and silicic alterations with moderate to increasing positive magnetic anomalies were associated. Also, propylitic alterations did not show a significant relationship with magnetic values.