Discrimination of Different Erosion Levels of Porphyry Cu Deposits using ASTER Image Processing in Eastern Iran: a Case Study in the Maherabad, Shadan, and Chah Shaljami Areas
Abstract:The Lut block, eastern Iran, is one of the most extensive Cenozoic magmatic rocks, that show suitable targets for porphyry Cu‐Au and high‐sulfidation epithermal Au related to porphyry Cu‐Au mineralization. In this study, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) was used to identify different erosion levels of three porphyry Cu deposits, including Maherabad, Shadan, and Chah Shalj ami, located in the Lut block volcanic‐plutonic belt. Alteration minerals, including kaolinite, dickit… Show more
“…The subvolcanic intrusive rocks are divided into five compositional groups, the relative ages of which has been established based on crosscutting relations and alteration type. From oldest to youngest, these groups are (a) hornblende quartz monzonite, (b) biotite-hornblende quartz monzodiorite to monzonite porphyry, (c) hornblende monzonite to monzodiorite porphyry, (d) monzonite porphyry and (e) hornblende diorite porphyry (Karimpour et al 2014). Laser-ablation U-Pb dating of syn-mineralisation dykes of the shadan deposit show that these groups were crystalised ∼39 Ma (Karimpour et al 2014).…”
Section: Geology and Mineralisationmentioning
confidence: 99%
“…From oldest to youngest, these groups are (a) hornblende quartz monzonite, (b) biotite-hornblende quartz monzodiorite to monzonite porphyry, (c) hornblende monzonite to monzodiorite porphyry, (d) monzonite porphyry and (e) hornblende diorite porphyry (Karimpour et al 2014). Laser-ablation U-Pb dating of syn-mineralisation dykes of the shadan deposit show that these groups were crystalised ∼39 Ma (Karimpour et al 2014). Figure 1 (a) Structural units of Iran and location of the Shadan area (modified from Jannessary et al 2012) and (b) 1:5000 simplified geological map of the study area (black polygon; modified from Hoshmandzadeh 2014).…”
Geochemical sampling media, be they rock chip, soil or stream sediment samples, routinely collected in mineral exploration, are key to detecting mineralisation-related geochemical dispersion patterns. Notwithstanding the diversity of methods applied to geochemical anomaly detection, they can be broadly divided into two major groups, namely structural and non-structural techniques. The former group covers those methods in which threshold values are assigned based on sample location while the sample locations are not required in the application of the non-structural techniques. In this study, rock chip samples from the Shadan porphyry copper-gold deposit are used to address the question as to how structural and non-structural methods can separate geochemical populations for the purpose of a deposit-scale study. It was revealed that the two structural techniques used in this study, concentration-area (C-A) fractal and U-spatial statistic methods, outperformed the nonstructural techniques employed in this study.
“…The subvolcanic intrusive rocks are divided into five compositional groups, the relative ages of which has been established based on crosscutting relations and alteration type. From oldest to youngest, these groups are (a) hornblende quartz monzonite, (b) biotite-hornblende quartz monzodiorite to monzonite porphyry, (c) hornblende monzonite to monzodiorite porphyry, (d) monzonite porphyry and (e) hornblende diorite porphyry (Karimpour et al 2014). Laser-ablation U-Pb dating of syn-mineralisation dykes of the shadan deposit show that these groups were crystalised ∼39 Ma (Karimpour et al 2014).…”
Section: Geology and Mineralisationmentioning
confidence: 99%
“…From oldest to youngest, these groups are (a) hornblende quartz monzonite, (b) biotite-hornblende quartz monzodiorite to monzonite porphyry, (c) hornblende monzonite to monzodiorite porphyry, (d) monzonite porphyry and (e) hornblende diorite porphyry (Karimpour et al 2014). Laser-ablation U-Pb dating of syn-mineralisation dykes of the shadan deposit show that these groups were crystalised ∼39 Ma (Karimpour et al 2014). Figure 1 (a) Structural units of Iran and location of the Shadan area (modified from Jannessary et al 2012) and (b) 1:5000 simplified geological map of the study area (black polygon; modified from Hoshmandzadeh 2014).…”
Geochemical sampling media, be they rock chip, soil or stream sediment samples, routinely collected in mineral exploration, are key to detecting mineralisation-related geochemical dispersion patterns. Notwithstanding the diversity of methods applied to geochemical anomaly detection, they can be broadly divided into two major groups, namely structural and non-structural techniques. The former group covers those methods in which threshold values are assigned based on sample location while the sample locations are not required in the application of the non-structural techniques. In this study, rock chip samples from the Shadan porphyry copper-gold deposit are used to address the question as to how structural and non-structural methods can separate geochemical populations for the purpose of a deposit-scale study. It was revealed that the two structural techniques used in this study, concentration-area (C-A) fractal and U-spatial statistic methods, outperformed the nonstructural techniques employed in this study.
“…One type of report concentrated on characterizing existing, known deposits in Iran. Karimpour et al [111] described discrimination of erosion levels in the Maherabad, Shadan, and Chah Shaljami areas. Mohebi et al [112] reported on delineation of structural controls on alteration and mineralization around Hanza Mountain.…”
Section: Aster Data Applied To Porphyry Copper Explorationmentioning
The Advanced Spaceborne Thermal Emission and Reflection Radiometer is one of five instruments operating on the National Aeronautics and Space Administration (NASA) Terra platform. Launched in 1999, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) has been acquiring optical data for 20 years. ASTER is a joint project between Japan’s Ministry of Economy, Trade and Industry; and U.S. National Aeronautics and Space Administration. Numerous reports of geologic mapping and mineral exploration applications of ASTER data attest to the unique capabilities of the instrument. Until 2000, Landsat was the instrument of choice to provide surface composition information. Its scanners had two broadband short wave infrared (SWIR) bands and a single thermal infrared band. A single SWIR band amalgamated all diagnostic absorption features in the 2–2.5 micron wavelength region into a single band, providing no information on mineral composition. Clays, carbonates, and sulfates could only be detected as a single group. The single thermal infrared (TIR) band provided no information on silicate composition (felsic vs. mafic igneous rocks; quartz content of sedimentary rocks). Since 2000, all of these mineralogical distinctions, and more, could be accomplished due to ASTER’s unique, high spatial resolution multispectral bands: six in the SWIR and five in the TIR. The data have sufficient information to provide good results using the simplest techniques, like band ratios, or more sophisticated analyses, like machine learning. A robust archive of images facilitated use of the data for global exploration and mapping.
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