Study on Core Hyperspectral Imaging and Its Significance in Exploration: A Case Study of Bangpu Large Polymetallic Deposit in Tibet
WU Chang-yu1, DAI Jing-jing1, 2*, SONG Yang1, 2, CHEN Wei1, 2, LIU Zhi-bo1, LIU Hong-cheng3, BAI Long-yang1
1. Ministry of Natural Resources, Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
2. SinoProbe Laboratory, Chinese Academy of Geological Sciences, Beijing 100094, China
3. National Key Laboratory of Remote Sensing Information and Image Analysis Technology，Beijing Research Institute of Uranium Geology，Beijing 100029, China
Abstract：Bangpu deposit in Tibet is an important porphyry-skarn deposit in the Gangdise metallogenic belt, and the research degree of the skarn ore body in the eastern part of its mining area is relatively low. Core hyperspectral imaging technology can quickly obtain the hyperspectral data of core samples. In this paper, the typical core samples of skarn in the eastern part of the Bangpu deposit are selected, and the short-wave infrared (SWIR) hyperspectral imaging test and comparative analysis are carried out by using the core scanner independently developed by the Beijing Research Institute of Uranium Geology and the foreign SPECIM core imager. At the same time, the SWIR spectral characteristics of typical minerals are revealed, and the potential and advantages of advanced hyperspectral imaging technology in skarn exploration are discussed. We carried out hyperspectral imaging tests on the same batch of core samples with domestic and foreign instruments. We extracted the end members using the minimum noise separation transform and pure pixel index. By consensus, this study identified six minerals: calcite, epidote, chlorite, hornblende, quartz, and muscovite. The mineral mapping results by the two instruments were generally consistent, reflecting the combination and distribution of different altered minerals. The mapping accuracy of SPECIM for ZK0010 and ZK0011 is 91.5%, and the Kappa coefficient is 0.87. The mapping accuracy of the samples by the Beijing Research Institute is about 75%, and the Kappa coefficient is 0.66.The signal-to-noise ratio of hyperspectral data obtained by the two instruments is high. However, due to domestic instruments' relatively low spatial resolution, there are more mixed pixels in the image, which affects mapping accuracy. Further improving its spatial resolution is the key point of the next research and development.The hyperspectral imaging data show that the wavelength of the Fe—OH absorption peak of chlorite in the ZK0010 drill hole ranges from 2 252.3~2 260 nm, and that of chlorite in the ZK0011 drill hole ranges from 2 251.7~2 258.5 nm. The wavelength shifts from top to bottom in the short wave direction, indicating that chlorite is far from the mineralization center and relatively rich in Mg. Its high value of the Fe—OH wavelength indicates the center position of the ore body. Hyperspectral imaging technology can provide more abundant spatial and spectral information than the traditional point measurement method, which provides technical support for extracting spectral characteristic parameters of indicator minerals and analyzing their variation rules.Based on a large number of spectral data provided by hyperspectral imaging, the Fe—OH peak position of chlorite is statistically analyzed, and the exploration of the skarn deposit can be indicated by its high wavelength position.
吴畅宇，代晶晶，宋 扬，陈 伟，刘治博，刘洪成，白龙洋. 岩芯高光谱成像及勘查指示意义研究——以西藏邦铺大型多金属矿床为例[J]. 光谱学与光谱分析, 2025, 45(01): 38-44.
WU Chang-yu, DAI Jing-jing, SONG Yang, CHEN Wei, LIU Zhi-bo, LIU Hong-cheng, BAI Long-yang. Study on Core Hyperspectral Imaging and Its Significance in Exploration: A Case Study of Bangpu Large Polymetallic Deposit in Tibet. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(01): 38-44.
