Wall-Rock Alteration, Structural Control, and Stable Isotope Systematics of the High-Grade Copper Orebodies of the Kennecott District, Alaska

2014 ◽  
Vol 109 (3) ◽  
pp. 581-620 ◽  
Author(s):  
J. B. Price ◽  
M. W. Hitzman ◽  
E. P. Nelson ◽  
J. D. Humphrey ◽  
C. A. Johnson
Keyword(s):  
Stable Isotope ◽  
Structural Control ◽  
Wall Rock ◽  
High Grade ◽  
Wall Rock Alteration ◽  
Rock Alteration ◽  
Isotope Systematics

scholarly journals Spectral Alteration Zonation Based on Close Range HySpex-320 m Imaging Spectroscopy: A Case Study in the Gongchangling High-Grade Iron Ore Deposit, Liaoning Province, NE China

2020 ◽  
Vol 10 (23) ◽  
pp. 8369
Author(s):  
Kun Song ◽  
Ende Wang ◽  
Yuzeng Yao ◽  
Jianfei Fu ◽  
Dahai Hao ◽  
...  
Keyword(s):  
Iron Ore ◽  
Spectral Characteristics ◽  
Wall Rock ◽  
Iron Deposit ◽  
Spectral Features ◽  
High Grade ◽  
Rock Interaction ◽  
Ore Body ◽  
Wall Rock Alteration ◽  
Rock Alteration

Research on wall rock alteration is of great importance to the understanding and exploration of ore deposits. The microscopic changes of the same mineral in different alteration zones can provide information about the migration and enrichment of ore-forming elements. In this paper, a typical profile of a high-grade iron ore body in Gongchangling iron deposit was investigated and sampled. The samples were checked by polarized microscopy, and alterations zonation were delineated according to the hydrothermal mineral assemblages and paragenesis. Moreover, hyperspectral images of wall rocks from each alteration zone were obtained by Norsk Elektro Optikk (NEO) HySpex-320 m imaging system. A customer Interactive Data Language (IDL) software package was used to process the images, and spectral features were extracted from the selected samples. The results indicate that spectral characteristics manifest obviously regular variations; i.e., from proximal to distal for the high-grade iron ore body, the wavelengths at ca. 1200 nm of chlorite and garnet, which accounts for most of the hydrothermal alteration minerals, become longer, and the absorption depths gradually smaller. The spectral features at 1200 nm of chlorite and garnet are always caused by the crystal field effect of Fe2+; therefore, the wavelength variations indicate the increase of Fe2+ and a reduced environment, which can provide more detailed information about the metallogeny and water–rock interaction. Since the hyperspectral features of the altered rocks can disclose unique mineralogical and structural information, the conventional classification of alteration zonation should be combined with the spectral feature, i.e., spectral alteration zonation, which is of great help to the understanding of the forming conditions of wall rock alteration and also the high-grade iron ore bodies.

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