Application of thermal infrared(TIR)spectral characteristics and magnetic susceptibility in the exploration of skarn deposits:A case study of the Tonglushan Cu-Au-Fe deposit,Edongnan ore district,Eastern China
The Tonglushan Cu-Au-Fe deposit in Hubei province is a large important skarn ore deposit in the Middle-Lower Yangtze River Metallogenic belt,Eastern China.The ore bodies mainly occur as lenticular and stratiform-like features in the contact zone between the Early Cretaceous quartz monzodiorite and its hypabyssal porphyry and(dolomitic-)marbles.In this study,49 minerals were identified in the Tonglushan ore deposit by using Thermal Infrared(TIR)analysis,including skarn and retrograde alteration minerals,alkali feldspar,plagioclase,quartz,and carbonates.Based on the macro/microscopic textural relationships and alteration mineral mapping,the following alteration zoning were identified,i.e.,skarn-hydrothermal mineralization center(alteration zone Ⅲ),endoskarn close to the skarn(alteration zone Ⅱ),and distal quartz monzodiorite(porphyry)(alteration zone Ⅰ)or(dolomitic-)marbles(alteration zone Ⅳ)from the mineralization center outward.Moreover,the Fe-Mg chlorite,Fe-chlorite,muscovite,saponite,kaolinite,skarn and retrograde alteration minerals show a significant increase near the skarn-hydrothermal mineralization center at Tonglushan.Moreover,the magnetic susceptibility analysis shows a significantly large variation(0-2000×10-3)within the Tonglushan mining area.Due to the high contents of ferromagnetic-and skarn minerals in the hydrothermal mineralization center,the high anomalies of MS occur near the hydrothermal mineralization center.In conclusion,the presence of Fe-Mg chlorite,Fe-chlorite,skarn and retrograde alteration minerals,Pos11400>11400 nm,and an increase of magnetic susceptibility in the samples can be used as new vectors to explore the mineralization centers in the Tonglushan Cu-Au-Fe skarn deposit.
thermal infrared(TIR)spectroscopymagnetic susceptibilityexploration indicatorskarn ore depositEdongnan ore district
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