3D alteration mapping and remote-sensing applications for porphyry -copper deposits (PCD) exploration, in Panagyurishte ore district, Bulgaria

The Panagyurishte ore district, Bulgaria is situated in the Srednogorie zone situated in the western part of the global Cu-Au dominant Tethyan-Eurasian Cu-Au metallogenic belt. Significant examples of Late Cretaceous volcano-plutonic structures with porphyry-copper deposits (Elatsite, Medet, Asarel, Tsar Assen, Vlaykov Vruh), connected to subvolcanic granodiorite porphyry intrusions occur in the Panagyurishte ore region, Bulgaria. The PSD are closely associated with high-sulphidation type Cu-Au epithermal deposits (Chelopech, Krasen, Radka, Elshitsa) that are related to andesite - dacite magmatic activity. 3D UAV-supported alteration mapping of Vlaykov Vruh and Tsar Assen PCD have been performed to identify and prove the geometry of the alteration mineral assemblages and ore controlling structures. Domains consisting of phyllic, argillic, propylitic and K-silicate alteration zones associated with and porphyry-copper style of mineralization in Vlaykov Vruh and Tsar Assen deposits were outlined. 3D modelling of Popovo Dere PCD by means of Leapfrog Geo and mineral alteration mapping study outlined fault controlled proximal K-silicate domain and more distal propylitic domain as a potential Cu-porphyry deposit target for further mineral exploration and evaluation

Two types of K-silicate alterations, one with magnetite and another without magnetite that hosted Cu-porphyry mineralization have been distinguished within the proximal Cu-rich zone. More distal propylitic domain has also been outlined by 3D modelling. Strike-slip fault control within the K-silicate alteration domain outlined the cone shaped Cu-porphyry ore body. The UAV-Multispectral and TIR mapping in addition to XRD study confirmed the geometry of phyllic alteration domain hosted in andesitic and dacitic volcanic rocks. The propylitic alteration zone is developed in the granodiorite porphyry intrusion in Vlaykov Vruh PCD and with K-silicate domains hosts Cu-Mo mineralization. Fe-oxide and malachite rich domains have been traced in Tsar Assen PCD in addition to Cu-rich zone in the western part of the open pit.

The recent study demonstrates that combined UAV-supported remote sensing and mineral alteration field and XRD mapping could provide an effective vectoring and exploration targeting tool toward PCD mineralization

This study is supported by the Horizon 2020 co-funded GOLDENEYE project through the Grant Agreement 869398.