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

Abstract

Abstract:One of the most important characteristics of porphyry copper deposits (PCDs) is the type and distribution pattern of alteration zones which can be used for screening and recognizing these deposits. Hydrothermal alteration minerals with diagnostic spectral absorption properties in the visible and near-infrared (VNIR) through the shortwave infrared (SWIR) regions can be identified by multispectral and hyperspectral remote sensing data. Six Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) bands in SWIR have been shown to be effective in the mapping of Al-OH, Fe-OH, Mg-OH group minerals. The five VNIR bands of Landsat-8 (L8) Operational Land Imager (OLI) are useful for discriminating ferric iron alteration minerals. In the absence of complete hyperspectral coverage area, an opportunity, however, exists to integrate ASTER and L8-OLI (AO) to compensate each other's shortcomings in covering area for mineral mapping. This study examines the potential of AO data in mineral mapping in an arid area of the Duolong porphyry Cu-Au deposit(Tibetan Plateau in China) by using spectral analysis techniques. Results show the following conclusions: (1) Combination of ASTER and L8-OLI data (AO) has more mineral information content than either alone; (2) The Duolong PCD alteration zones of phyllic, argillic and propylitic zones are mapped using ASTER SWIR bands and the iron-bearing mineral information is best mapped using AO VNIR bands; (3) The multispectral integration data of AO can provide a compensatory data of ASTER VNIR bands for iron-bearing mineral mapping in the arid and semi-arid areas.

Identification of Iron Oxides Minerals in Western Jahajpur Region, India Using Aviris-Ng Hyperspectral Remote Sensing

“…Field measured spectra have shown absorptions at 0.5070 μm, 0.6260 μm, 0.9310 μm, 1.4132 μm, 1.8080 μm. (Magendran and Sanjeevi, 2014, Murphy and Monteiro, 2013, Mielke et al, 2016, Roberto and Filho, 2000, Govil et al, 2018, Pour and Hashim, 2014, Pour and Hashim, 2015, Zhang et al, 2016, Boesche et al, 2015.…”

Identification of Hydrothermal Alteration Minerals for Exploring Gold Deposits Based on SVM and PCA Using ASTER Data: A Case Study of Gulong

“…Through the analysis of the distribution of gold deposits and the ore-bearing strata of the study area, the pyrite, sericite and chlorite are the most closely related to altered mineral of surrounding rock, which is a good prospecting indicator of gold ore [58][59][60].…”

“…Then, the result of the filter was stretched linearly by using 0-255 grey value. Finally, the mineralization information was segmented by using the average value plus standard deviation of 3.0 times as the threshold, and the segmentation result was as shown in Figure 7: rock, which is a good prospecting indicator of gold ore [58][59][60].…”

“…In general, the altered mineral formation of pyrite, sericite and chlorite are closely related to the hydrothermal alteration, so the altered zone has the characteristics surrounding rock mass distribution [60,61]. In addition, the alteration area is distributed both sides of the Limu-Majiang fault near the north-south direction, and in the south of the Pingxiang-Dali fault near the northeast direction, so the spatial distribution of the altered zone is closely related to the intrusive rocks and faults.…”

“…Those characteristics in combination can be used to identify the alteration zone and support mineral prediction. At present, many scholars have used multi-spectral data to identify the alteration zone based on above combination of characteristics [60,62,63].…”