عنوان مقاله [English]
Aeromagnetic data provide useful information for delineating magnetic basement, structural patterns, tectonics, and thermal status of the survey area. The current study presents the results of airborne magnetic studies in Basiran area (South Khorasan province) 100 km southwest of Birjand, that is well-known for its great mineral potential such as gold, copper, iron, manganese and silver. Appearance of Ghale-Zari, Bishe and the other active mines in the area indicate the promising mine potential of the region. Basiran area in the classification of the structural zones of Iran is located in the Lut Block. The Lut Block stretched over 900 km in the north-south direction and nearly 200 km in the east-west direction and bounded by the Nayband and Nehbandan faults. The lithology of the Lut Block is mainly lavas and pyroclastic rocks, as well as sub-volcanic rocks of Eocene-Oligocene ages eras. Volcanic rocks display a scattered pattern since they formed during the subduction to post-collisional stages between the Arabian and Asian plates. In 2005, a high-resolution airborne magnetic data collection (with flight line distances of 250 meters) was carried out in Basiran area of approximately 1500 km2 by the Geological Survey of Iran (GSI). The purpose of this survey is the study of the patterns of magnetic fields and their relationship with geological structures, especially iron bodies and to create a suitable exploration database for further investigations. The collected raw aeromagnetic data set are processed by applying Diurnal Variation correction and IGRF removal using Geosoft Oassis Montaj software. Processing of airborne data need applying other technical corrections such as lag compensation, topography and leveling in order to prepare the residual magnetic intensity data or TMA map (Total Magnetic Anomaly Map). In order to have a qualitative interpretation, we need to prepare all relevant maps to follow the anomaly variations. Then geophysical and mathematical filters are sequentially applied that routinely are the reduction-to-the pole (RTP) and upward continuation. The RTP map removes the latitude dependence of the magnetic fields and upward continuation maps bring and show the effect of the magnetic sources at depth. Based on the other studies results, in literature review, there are at least five main sources of anomalies in the Basiran area, which may be related to several magnetic and geological structures at depth. These sources are clearly at 300 m, 500 m and 1000 meters upward continuation maps. As the main results, this paper emphasizes on the key role of the aeromagnetic study to understand the relation between magnetic anomalies and the subsurface structures. Basiran area is a high potential area for mineral exploration that includes copper, gold, iron, and manganese that is made it valuable for many researchers that are active in mining exploration.