Identifying Potential Porphyry Cu Mineralization at the Kirazli District in Biga Peninsula (Nw Turkey): Insights From the Mapping Hydrothermal Alteration by Using Shortwave Infrared (Swir) Spectrometry

Abstract

The Kirazlı mineral district is located at the center of the Biga peninsula metallogenic province, in a geological setting characterized by an extensional tectonic environment. The district hosts a high-sulfidation (HS) ore body with a total reserve of 33.86 Mt @ 0.69 g/t Au and 9.42 g/t Ag within a large-scale hydrothermal alteration. Although the ideal magmatic-hydrothermal models present the spatial and temporal association of HS-epithermal and porphyry Cu deposits, the porphyry Cu potential at the Kirazlı has not been evaluated, yet. Therefore, the mineral-based alteration mapping with the help of SWIR reflectance spectroscopy was carried out. Our study demonstrates that nine different mineral zone have been distinguished and mapped: (1) Silicification, (2) Alunite, (3) Kaolinite, (4) Dickite, (5) Illite, (6) Pyrophyllite, (7) Chlorite, (8) Sericite, and (9) Montmorillonite zones. Collectively, these alterations exhibit a zoned pattern, from central massive silicification to residual silica, NW-SE oriented alunite, and marginal montmorillonite-illite zones within widespread kaolinite – dickite dominated alteration in Kirazlı main zone. The occurrence of pyrophyllite and sericite dominates at the SE of the Kirazlı district, which refers to relative temperature increase. Subsequent drilling confirms the potential for deep prospecting of porphyry Cu mineralization in the region.

Protracted metallogenic and magmatic evolution of the Kirazlı epithermal Au-Ag and porphyry Cu deposits, Biga Peninsula, NW Turkey: evidence from zircon U-Pb, muscovite 40Ar/39Ar, and molybdenite Re-Os geochronology

“…2 ). The strongly pervasive, widespread, and well-developed hydrothermal alteration zones at the Kirazlı deposit reflect typical patterns of an HS epithermal to porphyry Cu environment towards the Kale zone to the south-southeast (Aluç et al 2023 ; Fig. 4 ).…”

“…A core-to-rim zoned pattern, from central massive silicification and residual silica, quartz-alunite, a quartz-kaolinite halo, and an outer propylitic alteration envelope, is observed along an E-W-oriented transect at the Kirazlı Main. By contrast, sericitic alteration is more pronounced towards the south at the Kale zone for the porphyry Cu-style environment (Aluç et al 2023 ; Fig. 4 ).…”

“…4 ). Potassic alteration intersected in drill holes at the deeper part of the Kale zone (Aluç et al 2023 ).…”