期刊
GEOCARTO INTERNATIONAL
卷 37, 期 26, 页码 14105-14126出版社
TAYLOR & FRANCIS LTD
DOI: 10.1080/10106049.2022.2086633
关键词
Pegmatites; Li-bearing minerals; ASTER; Landsat 8OLI; TIRS; Sentinel-2MSI; band ratio; Afghanistan
This study aims to detect and highlight lithium-bearing pegmatites using spectral analysis in Southwest Konar province in Afghanistan, proposing new spectral indices for the detection of lithium-rich minerals. The research achieved a 71.1% overall accuracy in defining nine zones with lithium-bearing pegmatites, showcasing the effectiveness of ASTER data and thresholded band ratios for this purpose.
Lithium-cesium-tantalum (LCT) pegmatites are widely distributed in northeastern, eastern, and central Afghanistan. The largest rare-metal pegmatites having Lithium (Li)-bearing minerals occur in the Nuristan pegmatite belt in Eastern Afghanistan. The main aim of this study is to detect and highlight the Li-bearing pegmatites using spectral analysis within the Southwest Konar province in the east of Afghanistan and to establish self-proposed spectral indices for the detection of Li-rich minerals. To achieve the study's objective, we apply several algorithms, for example, false color composite, band ratio, and spectral angle mapper on ASTER, Landsat 8 OLI/TIRS, and Sentinel-2MSI data. Considering the spectral characteristics of key mineral spodumene and other diagnostic minerals, for example, lepidolite, amblygonite, and cookeite, which are considered diagnostic minerals of LCT pegmatites, particularly lithium, we utilize the ECOSTRESS Spectral Library-Version 1.0 for the interpretation of reflectance and absorption determinants of these minerals. Based on the diagnostic characteristics of the selected Li-bearing minerals, we examine several BRs and thresholding and consequently, propose new spectral indices which show a high concentration of spodumene, cookeite, and lepidolite over the northern regions of the study area. According to the obtained results, ASTER data and thresholded BRs present effective results compared to Landsat 8 OLI/TIRS. Based on the final outputs, we define nine zones having Li-bearing pegmatites, particularly over the Chapa Dara and Dara-e-Pech districts of southwestern Konar province, which could be promising areas of interest for further detailed exploration. Lastly, we compare the 118 known Li-bearing points collected from previous studies and field observations with the newly-defined zones to validate accuracy. The study's overall accuracy is 71.1%, indicating a good match between our findings and the reference points.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据