Hydrothermal alteration mapping from Landsat-8 data, Sar Cheshmeh copper mining district, south-eastern Islamic Republic of Iran

Abstract

This study presents the applicability of recently launched Landsat-8 data for hydrothermal alteration and lithological mapping aim at porphyry copper exploration in arid and semi-arid regions. Sar Cheshmeh copper mining district in the southeastern part of the Urumieh-Dokhtar volcanic belt, SE Iran has been selected as a case study. Several Red-green-Blue (RGB) color combination images and specialized band ratios were developed using Landsat-8 bands. Band ratios derived from image spectra (4/2, 6/7, 5 and 10 in RGB) allow the identification of altered rocks, lithological units and vegetation at a regional scale. Analytical imaging and geophysics developed hyperspectral analysis processing methods were applied to Landsat-8 bands to identify alteration zone associated with known porphyry copper deposits. Mixture Tuned Matched Filtering (MTMF) method was used to detect alteration zones associated with known porphyry copper deposits in the study area. Fieldwork, pervious remote sensing studies and laboratory analysis were utilized to verify the image processing results derived from Landsat-8 bands. It is concluded that Landsat-8 bands especially bands 2 and 4 in visible and near-infrared, 6 and 7 in shortwave infrared, and 10 in thermal infrared contain useful spectral information for porphyry copper exploration purposes. Moreover, thermal infrared bands of Landsat-8Page 2 of 32 A c c e p t e d M a n u s c r i p t 2 significantly improved the quality and availability of thermal infrared remote sensing data for lithological mapping. The achievements of this investigation should have considerable implications for geologists to utilize Landsat-8 Operational Land Imager (OLI)/ Thermal Infrared Sensor (TIRS) data for porphyry copper exploration and geological purposes in the future.

The Relationship between the Mixed Pixel Spectral Value of Landsat 8 OLI Data and LAPAN Surveillance Aircraft (LSA) Aerial-Photo Data

“…Landsat 8 Operational Land Imager (OLI) has been assessed by the users for looking at the area of hydrothermal alteration in a copper mine. It uses the existing thermal infrared (TIR) band and this data was able to be used to do lithological mapping (Pour and Hashim, 2015). The integrated use of Landsat and LIDAR to map forest structure and biomass was done by Zald et al (2016) in the area of Saskatchewan, Canada, which gained a moderate to high level of accuracy in the model (the value of R 2 = 0.42 to 0.69).…”

Lithologic Mapping using Remote Sensing Data in Abu Marawat Area, Eastern Desert of Egypt

“…This sensor measures the reflected electromagnetic waves in nine bands and measures the Thermal wavelengths in two bands (TIR). Several studies were used the OLI in imaging the hydrothermal alteration minerals (Zhang et al, 2016;Pour and Hashim, 2015;Abdelkareem and El-Baz, 2016).…”

Integrating Data of ASTER and Landsat-8 OLI (AO) for Hydrothermal Alteration Mineral Mapping in Duolong Porphyry Cu-Au Deposit, Tibetan Plateau, China

“…The five VNIR bands from the Operational Land Imager (OLI) sensor carried by the L8 satellite launched in 2013 have a broad bandwidth and a high SNR [43][44][45][46][47]. OLI has three additional VNIR bands compared with ASTER, two of which are at shorter wavelengths in the visible deep inside maximum charge transfer absorption and one at longer wavelengths spanning 0.845 to 0.885 µm covering part of the ferric oxide crystal field absorption of hematite and, to a lesser degree, goethite.…”