Late Cretaceous porphyry Cu and epithermal Cu–Au association in the Southern Panagyurishte District, Bulgaria: the paired Vlaykov Vruh and Elshitsa deposits

Abstract

Vlaykov Vruh-Elshitsa represents the best example of paired porphyry Cu and epithermal Cu-Au deposits within the Late Cretaceous Apuseni-BanatTimok-Srednogorie magmatic and metallogenic belt of Eastern Europe. The two deposits are part of the NW trending Panagyurishte magmato-tectonic corridor of central Bulgaria. The deposits were formed along the SW flank of the Elshitsa volcano-intrusive complex and are spatially associated with N110-120-trending hypabyssal and subvolcanic bodies of granodioritic composition. At Elshitsa, more than ten lenticular to columnar massive ore bodies are discordant with respect to the host rock and are structurally controlled. A particular feature of the mineralization is the overprinting of an early stage high-sulfidation mineral assemblage (pyrite ± enargite ± covellite ± goldfieldite) by an intermediate-sulfidation paragenesis with a characteristic Cu-Bi-Te-Pb-Zn signature forming the main economic parts of the ore bodies. The two stages of mineralization produced two compositionally different types of ores-massive pyrite and copper-pyrite bodies. Vlaykov Vruh shares features with typical porphyry Cu systems. Their common geological and structural setting, ore-forming processes, and paragenesis, as well as the observed alteration and geochemical lateral and vertical zonation, allow us to interpret the Elshitsa and Vlaykov Vruh deposits as the deep part of a high-sulfidation epithermal system and its spatially and genetically related porphyry Cu counterpart, respectively. The magmatichydrothermal system at Vlaykov Vruh-Elshitsa produced much smaller deposits than similar complexes in the northern part of the Panagyurishte district (Chelopech, Elatsite, Assarel). Magma chemistry and isotopic signature are some of the main differences between the northern and southern parts of the district. Major and trace element geochemistry of the Elshitsa magmatic complex are indicative for the medium-to high-K calc-alkaline character of the magmas. 87 Pb=37.497-38.630) allow attribution of ore-formation in the porphyry and epithermal deposits in the Southern Panagyurishte district to a single metallogenic event with a common source of metals.

Tectonic, magmatic, and metallogenic evolution of the Late Cretaceous arc in the Carpathian‐Balkan orogen

“…Whole rock samples were analyzed for major and trace elements and for Sr and Nd isotope ratios (see Text S1 in the supporting information for details). Additionally, we compiled geochemical whole rock data from previous studies of the Timok segment [ Kolb et al , ], the Panagyurishte segment [ Kamenov et al , ; Stoykov et al , ; Chambefort et al , ; Kamenov et al , ; Peytcheva et al , ; Kouzmanov et al , ; Peytcheva et al , ], and the Eastern Srednogorie segment [ S. Georgiev et al , ]. Major and trace element data are reported in Table S1 in the supporting information, and Sr and Nd isotopic data are reported in Table 2.…”

“…Five segments that show distinct magmatic and mineralization trends can be distinguished along this arc (Figure ). The timing and evolution of the magmatism and its associated ore deposits are well studied in the central and eastern segments [ von Quadt et al , ; Kamenov et al , ; Peytcheva et al , ; S. Georgiev et al , ; Kouzmanov et al , ; Peytcheva et al , ; Georgiev et al , ; Kolb et al , ]. However, information on the northwestern Banat and Apuseni segments is still scarce [ Zimmerman et al , ].…”

Subaqueous environment and volcanic evolution of the Late Cretaceous Chelopech Au–Cu epithermal deposit, Bulgaria

“…The Panagyurishte district has produced approximately 95% of the Bulgarian copper and gold (Mutafchiev and Petrunov, 1996). The Panagyurishte ore district is defined by a north-northwest alignment of porphyry Cu and epithermal Au-Cu deposits dated between about 92 and 78 Ma (Handler et al, 2004;von Quadt et al, 2005;Chambefort et al, 2007;Kouzmanov et al, 2009) with a gradual younging of magmatic and ore forming events from north to south, attributed to slab retreat or slab roll-back. This district is characterized by northwest-west trending horst and grabens, related to dextral strike-slip deformation, associated with post-collisional Alpine extension (Ivanov et al, 2001;Chambefort and Moritz, 2006).…”

Magmatic-hydrothermal evolution of the Cretaceous Duolong gold-rich porphyry copper deposit in the Bangongco metallogenic belt, Tibet: Evidence from U-Pb and 40Ar/39Ar geochronology

“…The porphyry deposits of the Yulong and Gangdese metallogenetic belt respectively formed in the Eocene and Miocene, and both of them belong to Cu-Mo mineralization assemblage and formed in a post-collision geotectonic setting Qu et al, 2004Qu et al, , 2007Qu et al, , 2009Qin et al, 2005Qin et al, , 2006Liang et al, 2006Liang et al, , 2009. In addition, the Bangongco metallogenic belt is analogous to the Panagyurishte ore district of the Srednogorie zone in Bulgaria, which formed in the Late Cretaceous (Von Quadt et al, 2002Quadt et al, , 2005Tarkian et al, 2003;Kouzmanov et al, 2009) and is present in the western segment of the Tethyan-Himalaya metallogenetic province. The Late Cretaceous Elatsite porphyry deposit (located about 55-60 km east of Sofia, Bulgaria) in the Panagyurishte ore district has a Cu-Au-PGE mineralization assemblage and was formed in an arc setting (Von Quadt et al, 2002Tarkian et al, 2003), resembling the Duolong mineralization.…”