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Application of Spectral Angle Mapper Classification to Discriminate Hydrothermal Alteration in Southwest Birjand, Iran, Using Advanced Spaceborne Thermal Emission and Reflection Radiometer Image Processing
Author(s) -
ABDI Maryam,
KARIMPOUR Mohammd H.
Publication year - 2012
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.2012.00748.x
Subject(s) - geology , geochemistry , hydrothermal circulation , mineralogy , alunite , mineral , ilmenite , advanced spaceborne thermal emission and reflection radiometer , remote sensing , materials science , digital elevation model , seismology , metallurgy
The purpose of this study is to evaluate the Spectral Angle Mapper (SAM) classification method for determining the optimum threshold (maximum spectral angle) to unveil the hydrothermal mineral assemblages related to mineral deposits. The study area indicates good potential for Cu‐Au porphyry, epithermal gold deposits and hydrothermal alteration well developed in arid and semiarid climates, which makes this region significant for Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image processing analysis. Given that achieving an acceptable mineral mapping requires knowing the alteration patterns, petrochemistry and petrogenesis of the igneous rocks while considering the effect of weathering, overprinting of supergene alteration, overprinting of hypogene alteration and host rock spectral mixing, SAM classification was implemented for argillic, sericitic, propylitic, alunitization, silicification and iron oxide zones of six previously known mineral deposits: Maherabad, a Cu‐Au porphyry system; Sheikhabad, an upper part of Cu‐Au porphyry system; Khoonik, an Intrusion related Au system; Barmazid, a low sulfidation epithermal system; Khopik, a Cu‐Au porphyry system; and Hanish, an epithermal Au system. Thus, the investigation showed that although the whole alteration zones are affected by mixing, it is also possible to produce a favorable hydrothermal mineral map by such complementary data as petrology, petrochemistry and alteration patterns.