Hydrothermal epidote types,composition and prospecting significance in ?ukaru Peki copper-gold deposit,Serbia
The Čukaru Peki Cu-Au deposit is a recently discovered giant porphyry-epithermal Cu-Au deposit in the western Tethys metallogenic domain,Serbia. It is primarily found in Late Cretaceous andesite containing horn-blende and plagioclase and exhibits distinct alteration zoning characteristics,making it an ideal subject for studying the exploration index system of altered minerals. In this study,we analyzed the mineral chemical composition of epidote in the deposit using microscopic electron probe microanalysis (EPMA) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) techniques while considering drilling catalog information.Based on the occurrence of epidote,we divided it into two types:type Ⅰ epidote found in the phyllic alteration zone and type Ⅱ epidote found in the propylitic alteration zone. The results derived from electron probe analyses indicate negative correlations in both varieties of epidote between the content of Al and Fe,and Ca and Mn,while the contents of Al,Fe,and Mn were obviously different. Type Ⅰ epidote was poor in Fe and Mn,rich in Al elements,with a relatively low XFe value. Type Ⅱ epidote exhibits an enrichment in Fe and Mn and low in Al elements,indi-cating higher XFe ratios. Combined with the mineral phase characteristics,we propose that type Ⅰ epidote is al-tered by plagioclase,and type Ⅱ epidote is altered by hornblende. This suggests that the variations in the major elements of epidote are governed by the minerals present prior to alteration. The results of LA-ICP-MS analysis indicate an increasing trend in the contents of Pb,Sb,and Ba from deep to shallow in the propylitic alteration zone,while shallow epidote shows low Mo content. In type Ⅱ epidote,the contents of Mn,Al,and Mg increase initially with depth before decreasing,whereas the contents of As,Fe,and Ca exhibit the opposite trend. Due to the influence of temperature and other physicochemical conditions on the variation of trace element indicators in epidote,the spatial distribution patterns of Mg,Pb,Sb,Ba,Mo,Mn,and As in epidote from the Cukaru Peki cop-per-gold deposit suggest that the hydrothermal center of this porphyry-type deposit is located 1～2 kilometers be-neath the Mn anomaly. Additionally,it is noted that major elements such as Al and XFe in type Ⅱ epidote display similar variations with Mn trace elements,while Ca and Fe exhibit opposing trends. Consequently,it is suggested that Al,XFe,Ca,and Fe within type Ⅱ epidote could serve as innovative indicators for mineral exploration.
epidotemain and trace elementsporphyry copper-gold depositmineral explorationČukaru Peki copper-gold deposit
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