Large-scale mapping of iron oxide and hydroxide minerals of Zefreh porphyry copper deposit, using Worldview-3 VNIR data in the Northeastern Isfahan, Iran

Abstract

Discrimination of iron oxide and hydroxide mineral assemblages is a key factor in porphyry copper exploration. This paper investigates the ability of the Worldview-3 VNIR data in mapping iron oxide / hydroxide minerals associated with the porphyry copper mineralization. The study area is situated in the central part of the Urumieh–Dokhtar magmatic arc, northeastern Isfahan, Iran, which hosts a number of important porphyry copper deposits. The copper mineralization is related to the porphyry intrusive complex that ranges in composition from diorite to granodiorite. Bands 2,3,4,5, and 8 of this satellite were used to enhance the pixels containing target minerals and to mask the effects of vegetation on these pixels. The best results in terms of mapping and discriminating target materials were acquired by the band math and the matched filtering (MF) methods. The MF output results enhanced pixels with the highest fractions of the target minerals. The field investigations, X-ray diffraction (XRD) analysis, and microscopic studies showed that the distribution pattern of target minerals correspond well to ground criteria and gossan caps associated with the porphyry copper mineralization. It was concluded that Worldview-3 has the efficient spectral bands in VNIR region, which could be proposed for the iron oxide / hydroxide mineral mapping.