Application of Spectral Angel Mapper classification to discriminate hydrothermal alteration in SW Birjand, Iran by using ASTER image processing

Abstract

The intention of this study is evaluating the Spectral Angel Mapper (SAM)<br><br>classification method to select optimum threshold (Maximum spectral angel) to disclose the<br><br>hydrothermal mineral assemblages related to mineral deposits. The study area indicates good<br><br>potential for Cu-Au porphyry and epithermal gold deposits and hydrothermal alteration was<br><br>well developed in arid and semi-arid climate which significant it to evaluate ASTER image<br><br>processing analysis. To achieve an acceptable mineral mapping needs to know<br><br>petrochemistry and petrogenesis of igneous rocks, alteration patterns and consider the effect<br><br>of weathering, overprinting of supergene alteration, overprinting of hypogene alteration and<br><br>host rock spectral mixing.<br><br>SAM classification was implemented for argillic, sericitic, propylitic, alunitization,<br><br>silicification and iron oxide zones of six previously known mineral deposits, Maherabad, a<br><br>Cu-Au porphyry system, Sheikhabad, an upper part of Cu-Au porphyry system, Khoonik, an<br><br>Intrusion related Au system, Barmazid, a low sulfidation epithermal system, Khopik, a Cu-<br><br>Au porphyry system, Hanich, an epithermal Au system.<br><br>The investigation define that all of alteration zones are affected by mixing but it is<br><br>possible by complementary data such as petrology, petrochemistry and alteration patterns<br><br>produce an acceptable hydrothermal mineral map.