Study on mineral exploration by infrared multi-spectral approach
Zhen Lanfen
Institute of Remote Sensing Application, CAS
Yang Bolin
Guiyang Institute of geological Chemistry, CAS
din Xuan
Gangzhou Institute of New Geological Technology, CAS
Tong Qingxi
Institute of Remote Sensing Application, CAS
Xue Yongqi
Shaghai Institute of Technical Physics, CAS
Abstract
In recent years, the fine split infrared multispectral scanning remote sensing technology has been newly developed for mineral exploration by the Chinese Academy of sciences. With the support of the Bureau of Earth Resources and Environment, the Chinese Academy of Sciences (CAS),several institutes of CAS cooperated closely, and used the fine-split spectral scanning remote sensing technology to acquire mineralizing alteration information, and directly to detect the gold resources in Xinjiang area. A great progress has been made and a breakthrough had been obtained. These units are ; the Institute of remote Sensing Application (Airborne Remote Sensing center), the Shanghai Institute of Technical Physics, the Guiyang Institute of Geological Chemistry, the Guangzhou Institute of New Geological Technology, the Annuli Institute of Optics and Fine Mehcanics, the Xinjiang Institute of Geography and so on. The Gold mineralized zone and mineralization are have been discovered in the western Zhunger area, Xinjiang, through a serial research procedure for mineral exploration; spectrum measurement and analysis, interpretation of satellite image, airborne remote sensing and image processing, geological engineering verification of image spectral anomaly and so on. It is reveled that the fine split infrared spectral remote sensing is a fast and effective new technology for mineral exploration, and has a vast application prospect.
Theoretical basis for file split infrared spectral scanning Remote Sensing technology on exploration
It was found by a large number of data at home and aboard that all kinds of rock and mineral component, especially alteration of rock type and intensity, spectral signature are different in the short wavelength infrared range of 2.00 - 2.50
mm; there are obvious spectral absorption features. These spectral features result from vibration of the chemical compounds combined with OH
-
CO
32-Al-OH Mg-OH Fe
3+. NH
4 etc inside components of the alteration mineral and rock. Due to vibration frequency, double frequency and compound frequency inside ions, a kind of rock or mineral usually has some absorption peaks in the band mentioned above. Therefore, according to the features, mentioned above, of different rocks and minerals, the correlation model between the fine-split spectral band and alteration types, alteration intensity can be established by the located wavelength position, width and depth of their absorption peaks as an indicator of quality and quantity Fig. 1 shows the relative reflectance curve of several typical rocks and minerals in the western Zhunger area, Xinjing.
Fig. 1 Reflectance curve of several major types of rock and mineral in the western Zhunger area, Xinjiang.
In order to make full use of fine-split infrared technology for remote sensing geological mineral exploration in the western Zhunger area, Xinjiang, a great quantity of field spectral measurement and analysis of surface features have been carried out for a number of existed gold mineral zone in test area, spectral absorption features of the major types of rock and mineral were obtained, and remote sensing spectral database in thematic geology was established in 1986.
