ASTER SPECTRAL ANALYSIS FOR HOST ROCK ASSOCIATED WITH PORPHYRY COPPER-MOLYBDENUM MINERALIZATION
This study investigates the application of spectral image processing methods to ASTER data for mapping host rock associated with porphyry copper-molybdenum mineralization. The application of remote sensing in identifying variations in surface mineralogy, structural elements, and lithologic contacts can help in identifying such relations. Signatures collected from the Reﬂection Radiometer (ASTER) data is used to map the host rock of Zafarqand area. The study area is located in the central segment of the Urumieh–Dokhtar Volcanic Belt of Iran. The Urumieh-Dokhtar is a potential zone for exploration of new porphyry copper deposits. Band ratio, Band math, False color composites and Principal component analysis techniques are used to refine the different lithologic units in the area. These methods showed the discrimination of acidic igneous from mediocre igneous and the boundary between igneous rocks using the shortwave infrared bands (SWIR) of ASTER at regional scale. Results have proven to be effective and in accordance with the results of field surveying and ore microscopy examination and with reference geological map. In conclusion, the image processing methods used can provide cost-effective information to discover possible locations of porphyry copper and epithermal gold mineralization prior to detailed and costly ground investigations. The extraction of spectral information from ASTER data can produce comprehensive and accurate information for copper and gold resource investigations around the world, including those yet to be discovered.
Key words: porphyry copper; ASTER; PCA; band ratio; Zafarqand