M.J Mohammadzadeh; A Nasseri; S Ansari
Abstract
Sahebdivan area is located at 20.km of Meshkinshahr in Ardebil province. The study area is comprises of volcanic rocks and intrusive masses consisting of quartz monzonite and granite along with several vast epithermal alterations. The main objective of this paper is to recognize the present ...
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Sahebdivan area is located at 20.km of Meshkinshahr in Ardebil province. The study area is comprises of volcanic rocks and intrusive masses consisting of quartz monzonite and granite along with several vast epithermal alterations. The main objective of this paper is to recognize the present alteration zones indicating metal promising areas using geophysical methods such as induced polarization (IP) surveying and resistivity (RS) in order to assess the presence of minerals and delineate the subsurface masses at depth. Therefore, IP/resistivity survey was carried out based on rectangular array in the area and their corresponding maps were prepared. Accordingly, their promising anomalous zones for mineralization were initially detected. Furthermore, a new IP survey was attempted based on a dipole-dipole electrode array for detailed potential mapping.
Considering IP/RS pseudo-sections, the position, depth, intensity and extent of mineralization was defined. Correlating the anomalous zones obtained from geophysical results with Lithology and alteration zones in the area indicate Cu mineralization along E-W trend in Sahebdivan which is associated with increase in chargeability and reduction in resistivity. Furthermore topographic corrections were attempted resulting in anomalous halos enhancement. Discriminating the important alteration zones in the area were carried out based on chargeability variations where higher chargeability indicate phyllic alteration with pyrite and in contrast the Potassic alteration with low chargeability that coincide with igneous intrusive.
It can be deduced from this study that the porphyry micro quartz monzonite - micro quartz diorite generator fluids was recognized as source of mineralization along with surrounding andesite–dacite andesite as source of the anomalous zones in Sahebdivan area. Summing all the evidences from field studies and their compliance with geophysical results, Lithology, alterations and ultimately considering the susceptible mineralization zones, the optimal drilling points was proposed with priority of SABH-1 according to the Potassic zone in terms of potential copper mineralization.
S Ansari; F Yaminifard; M Tatar
Abstract
In this study, 23 focal mechanisms were calculated by moment tensor inversion of small regionalـlocal earthquakes in the Western Alborz and surrounding areas using wave-form inversion method. Calculated reverse-fault focal mechanisms around the Khazar and Alborz Faults in the Central Alborz, considering ...
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In this study, 23 focal mechanisms were calculated by moment tensor inversion of small regionalـlocal earthquakes in the Western Alborz and surrounding areas using wave-form inversion method. Calculated reverse-fault focal mechanisms around the Khazar and Alborz Faults in the Central Alborz, considering southward-dipping nodal plane as the fault plane, are consistent with relatively low-angle thrusts. It also implies dominant compressionsl regime in the north of the Central Alborz. Focal mechanisms in 1990 Rudbar-Tarom Earthquake region show a combination of strike-slip mechanisms and a complex fault system in the middle of the Western Alborz. A major region of dominant strike-slip mechanisms is observed in the Talesh area, located in the west of the SouthCaspianBasin, and around the Masuleh, Sangavar and Bozqush faults. The only calculated focal mechanism close to the southern margin of the Western Alborz, considering the western part of the North Tehran fault as the fault nodal plane, implies leftـlateral motion in this area. In the south of the western AlborzMountains approaching the Central Iran, two calculated mechanisms indicate dominant reverse movement, similar to the 2002 Changoreh-Avaj Earthquake. Five focal solutions close to the Kushk-e Nosrat and Soltanieh Faults, considering these faults as the fault nodal planes, are consistent with right-lateral motion along them. Depth of the earthquakes in the studied region is in the range of 2 and 20 km, indicating the brittle upper crust in the region.
