| 基于遥感短波红外技术的三维蚀变填图——以低硫化浅成低温热液型矿床斯弄多为例 |
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| 关键词:low-sulfidation epithermal deposit Sinongduo shortwave infrared ASTER mineral index |
| 基金项目:国家自然科学基金青年科学基金(编号: 41302265);国土资源部公益性行业科研专项(编号: 201511017-4) |
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| 3D Geological Alteration Mapping Based on Remote Sensing and Shortwave Infrared Technology: A Case Study of the Sinongduo Low-sulfidation Epithermal Deposit |
| The Sinongduo Ag (Au)-Pb-Zn deposit is the first low-sulfidation epithermal deposit discovered in the volcanic rocks of the Linzizong Group on the southern margin of Gangdise. This discovery is of great significance for perfecting the regional metallogenic series and expanding the regional prospecting. The authors used the method of remote sensing technology and shortwave infrared technology to reproduce the surface-underground alteration mineral assemblage by 3D modeling and form a three-dimensional alteration map of star-air-ground integration. The extraction of surface alteration mineral features was based on multi - spectral remote sensing ASTER data, whereas iron index (b2+b3)/b1, magnesium hydroxyl index (b6+b9)/(b7+b8), and aluminum hydroxyl index (b5/b8)+(b6/b9) were used to extract the mineral information of Fe3+, Fe2 +, Al-OH and Mg-OH groups on the surface of the mine. For underground alteration mineral information extraction, the authors used short-wave infrared technology, spectral matching, decoupling and other methods to extract the alteration information of the core minerals sericite, montmorillonite and illite. According to the characteristics of subsurface alteration mineral assemblage, some conclusions have been reached: (1) It is found that the Al-OH alteration on the surface is consistent with the underground sericite, and hence the remote sensing Al-OH information can be used as an important prospecting clue. (2) According to the distribution of underground alteration minerals, it is possible to determine the fact that the alteration of iron minerals on the surface is mainly manifested as a large amount of limonite mineralization (obvious field characteristics) and a small amount of jarosite and sericite. (3) The formation of sericite causes a change of its octahedral structure: AlⅥAlⅣ?MgⅥSiⅣ and Fe?Mg, which is an important reason for the superposition of Mg-OH groups upon Al-OH information on the surface. (4) The calculation of the characteristic parameters of illite in the drill hole shows that the crystallinity of illite (SWIR-IC) exhibits regular changes in the drill hole: that is, the SWIR-IC (1.1 ~ 1.4) in the near-mine area is lower, and the formation temperature of the illite is lower, indicating that it is probable that the conversion of montmorillonite to illite in the process of diagenesis of clay minerals is progressive, thus the SWIR-IC (1.6 ~ 2.1) is higher in the distant part, and the formation temperature of the illite is lower, indicating that the formation of the mineral in terms of relatively high temperature is relatively high, which is the specific reflection of sericite. |
| HUANG Yi-ru,GUO Na,ZHENG Long,YANG Zong-yao,FU Yuan.2017.3D Geological Alteration Mapping Based on Remote Sensing and Shortwave Infrared Technology: A Case Study of the Sinongduo Low-sulfidation Epithermal Deposit[J].Acta Geoscientica Sinica,38(5):779-789. |
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