Aeromagnetic features in the northwest Lut block: related toCenozoic tectonism

The study area is located in northwest part of Lut block. The area is separated into two different blocks by the Nayband right-lateral fault: the relatively high Tabas block to the west and the low Lut block to the east which have different geology. An insufficient road system makes the area inaccessible and few field investigation has performed in this region. In this study we used aeromagnetic data to identify underground geological structures which may not be exposed to the surface. The airo-magnetic data used for this study come from investigations performed by Geological Survey of Iran (GSI) during 1974 to 1978, with a line space of 7.5 km. For data analysis, first we drew magnetic lineaments and determined magnetic lineament trends. Some of these lineaments are coincide with the geological faults and others are interpreted as linear features or buried faults. In the next step, qualitative interpretation employing several filters has been performed to the data to obtain information about geological subsurface structures. Wavelength filtering of the magnetic field used to enhance geological structures at different depth levels. The high-pass filtering highlighted shallower sources and small structures. On the other hand, low-pass magnetic filtering was used to highlight structures that represent upper crustal variations. Different wavelength cut-off filters were used to isolate the short, the long and the intermediate wavelength patterns. Qualitative interpretation maps demonstrate a clear difference in magnetic anomaly patterns in the west part of the Nayband fault compare to the east part. Maps reveal very low magnetic anomalies in the western part which is due to the low magnetic sedimentary units of Tabas block. On the contrary, rock unites of eastern part (Cenozoic volcanic units of Lut bock) display magnetic highs.Employing horizontal gradient of pseudo gravity anomalies. We delineated exact boundaries for deep and shallow sources and could determine an approximate location for each magnetic source.Finally, a 2D forward modelling was prepared to obtain a geological model for the observed aeromagnetic data. This model suggests low magnetic sedimentary units in the western part of Nayband and fractures, magma uplifting and creation of high magnetic igneous intrusions, in the eastern part of this rightlateral fault.