Integration of Concentration-Area Fractal Modeling and Spectral Angle Mapper for Ferric Iron Alteration Mapping and Uranium Exploration in the Xiemisitan Area, NW China

Abstract

Abstract:The high-grade uranium deposits in the Xiemisitan area, northwestern China, are genetically associated with the faulting of felsic volcanic or sub-volcanic rocks. Ferric iron alteration indicates that oxidizing hydrothermal fluids percolated through the rocks. In this study, we measured the gamma-ray intensities of rocks in the Xiemisitan area and we propose a hybrid method for the mapping of ferric iron alteration using concentration-area fractal modeling and spectral angle mapper. The method enables ferric iron alteration to be distinguished from potash-feldspar granitic rocks. The mapping results were integrated with structural data to assist with exploration for uranium in the study area. Using this approach, six prospective areas of mineralization were proposed. Of these areas, two anomalies with high gamma-ray intensities of 104 and 650 Uγ were identified and verified by field inspection. These observations suggest that Enhanced Thematic Mapper Plus images are a valuable tool that can improve the efficiency of uranium exploration.

Reflectance Spectroscopy Characteristics of Turquoise

“…Hyper-spectral imaging has been widely used in geological mapping [8][9][10][11], ore exploration [12][13][14], nature conservation [15][16][17][18], and food or drink quality analysis [19,20]. Recent studies have also used this technology to conveniently and economically examine ancient documents and archaeological artifacts [21][22][23].…”

Hyperspectral Alteration Information from Drill Cores and Deep Uranium Exploration in the Baiyanghe Uranium Deposit in the Xuemisitan Area, Xinjiang, China

“…Then, we used the Spectral Analyst of ENVI 4.8 to analyze quantitatively spectra with the reference spectral library of the United States Geological Survey (USGS), and the ENVI 4.8 software platform was used to transform the spectral curve data into a spectral library. Finally, the spectral characteristics and mineral identification of every curve were individually analyzed using the spectral library of the United States Geological Survey (USGS) via visual interpretation analysis data to more accurately confirm minerals once again, and to examine these spectra after Spectral Analyst of ENVI [7,28], according to the data processing workflow in Figure 4. The spectral characteristics were analyzed in terms of the form of each spectral curve, the wavelength location of the main absorption peak, and the combination features of the absorption peak.…”

“…Moreover, in the Xuemisitan area, the Chagantaolegai-Bayinbulake Fault and the volcanic system, which included Yangzhuang, Xuemisitan, the Qiyi work area, the Shiyue work area, and Mamente, are favorable for uranium mineralization, where similar alteration developed including hematitization, illite alteration, fluoritization, silicification, chloritization with carbonatization, with many uranium mineralization areas forming [6,7]. We conclude that illite alteration (hydromicazation), hematitization and fluoritization were closely related to the uranium mineralization in the Baiyanghe uranium deposit and that the resulting minerals can be used as uranium-prospecting indicators during the exploration of the deeper sections of the Xuemisitan area.…”

“…Landsat 7 and Quickbird remote-sensing images were used to interpret volcanic features in the Baiyanghe mining area by Lu et al [6], who also analyzed the characteristics of the cryptovolcanic rock mass, the alteration distribution and its influences, and the possible uranium metallogenic position. An Enhanced Thematic Mapper Plus image was used by Qiu et al [7] to map ferric iron alteration during uranium exploration in the Baiyanghe uranium deposit. Furthermore, Geological Team 216 conducted considerable drilling work and estimated the uranium ore reserves in the Baiyanghe deposit [8].…”

Reflectance Spectral Characteristics of Minerals in the Mboukoumassi Sylvite Deposit, Kouilou Province, Congo

“…discontinuously from drill cores, and the dissolution method for separating carnallite from halite is time-consuming and uneconomic. Hyperspectral remote sensing, which has been successfully used in lithological classification [1][2][3][4][5] and alteration mineral identification [6][7][8], provides a potential alternative for halite estimation and carnallite separation in the solid state. Materials that interact with the electromagnetic waves emitted from the sun can be recorded by hyperspectral sensors in the form of a spectrum.…”