Remote sensing detection of altered zones associated with Cu-Mo mineralization in North of Zahedan, SE Iran using Landsat-8 data

Authors : Rahele Moradi, Mohammad Boomeri

Pages : 275-294

View : 9 | Download : 4

Publication Date : 2017-12-03

Article Type : Research

Abstract :Hydrothermal alteration zones have highlighted role in prospecting mineral deposits. In this study and at the first stage, we used image processing techniques on the Landsat-8 image which covered the Lar area located in southeastern part of Iran. We applied the color composite, band ratio, Crosta and LS-Fit methods, high-pass directional filtering, and photolineament factor methods. The color composite and band ratio methods clearly showed the hydrothermal altered areas of clay minerals and iron oxides that are in compliance with the maximum amount of fractures. Both LS-Fit and Crosta methods enabled us to represent and acknowledge the altered hydroxyl and iron-oxide minerals in the study region. Finally, the high-pass directional filtering and photolineament factor methods were administered to map the geological structures and to determine the intense influences of hydrothermal fluids location. In the second stage, based on field observation, we managed to determine hydrothermal alterations as silicic, potassic, argillic, propylitic and phyllic without any normal zonation of porphyry deposits. Altered and mineralized area has an oval shape, with a NW-SE strike, mainly concentrated in the southwest of the Lar igneous complex. Mineralization often occurs in syenitic to monzonitic intrusions and in association with silicic veins and veinlets. Consequently, the results of image processing techniques showed high efficiency for mapping hydrothermal altered areas especially iron-oxide minerals which are alteration products of hydrothermal sulfides. These methods enabled us to identify the first Cu-Mo porphyry system in southeastern part of Iran before costly-detailed ground investigations.
Keywords : hidrotermal bozunmanın haritalanması, Landsat-8, Crosta yöntemi, LS-Fit yöntemi, Lar Cu-Mo porfiri sistemi, fotoçizgisellik faktörü