A Remote-Sensing-Based Alteration Zonation Model of the Duolong Porphyry Copper Ore District, Tibet

Fojun Yao,Xingwang Xu,Xinxia Geng,Jianmin Yang

doi:10.3390/rs13245073

Abstract

Remote sensing (RS) of alteration zones and anomalies can provide information that is useful for geological prospecting and exploration. RS is an effective method for porphyry copper mineral exploration and prospecting prediction. More specifically, the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) data, which include 14 spectral channels from visible light to thermal infrared, are useful in such cases. This study uses visible-shortwave infrared and thermal infrared ASTER data together with surface material spectra from the Duolong porphyry copper ore district to construct an RS-based alteration zonation model of the deposit. In this study, an RS alteration zoning model is established based on ground-spectral alteration zoning results. The methods include PCA (Principal Component Analysis), Ratio, and Slope methods. The information obtained by each method is different. RS-based alteration zonation is developed based on the intersection of maps, resultant from the different methods for extracting information related to different minerals. The alteration zonation information extracted from ASTER RS data is consistent with geological observations. Using information from the RS-based model, we mapped the alteration minerals and zones of the Duolong ore district, thereby identifying prospecting target areas of the deposit.

Highlights

Multi-spectral remote sensing (RS) techniques have been increasingly and successfully applied in geological prospecting
According to analysis results of the spectra of surface samples using PimaView software, the alteration mineral assemblage of the Duobuza and Bolong deposits comprises of 18 kaolin, white-mica, smectite, chlorite, epidote, carbonate, but 10% of the samples10are invalid
The RS-based model of alteration zonation constructed for the Duolong ore district was integrated with various prospecting factors in the western part of the Bangong–Nujiang metallogenic belt

Summary

Introduction

Multi-spectral remote sensing (RS) techniques have been increasingly and successfully applied in geological prospecting. Work in this area includes the recognition of limonite alteration using Landsat multi-spectral data [1], as well as the extraction of the spectral characteristics of hydroxyl minerals in the visible near-infrared (VNIR) to short wave infrared (SWIR) bands [2,3]. Besides PCA, other techniques for extracting remote-sensing-based alteration information include the ratio method, spectral angle mapper (SAM), minimum noise fraction (MNF), and linear spectral unmixing (LSU) [8,9,10,11,12].

Results

Discussion

Conclusion