LITHOGEOCHEMICAL FOOTPRINT OF ALTERATION AND MINERALIZATION AT THE MESKAN PB-ZN DEPOSIT (HAKKARI, SOUTHEAST ANATOLIA)

Date

2024-4-26

Author

Karataş, Göksu

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The Meskan carbonate-hosted Pb-Zn deposit, located in the Hakkari district in SE Anatolia, formed along the northern passive margin of the Arabian Platform. The predominant components of the host rocks consist primarily of carbonate micrite mudstones and claystones, with a lesser proportion of interlaminated grainstonemudstone formations. These rock units are mainly composed of calcite, with dolomite present in smaller quantities. Additionally, hydrothermal processes have influenced these rocks, resulting in the alteration and partial replacement of calcite and dolomite by sulfides, barite, and carbonates (predominantly calcite). Banded dolomitic alteration (zebra dolomite) and dolomite-matrix breccias are associated with mineralization. The sulfide mineralization is characterized primarily by very fine to medium-grained pyrite dominance, along with sphalerite, galena and marcasite. Mineralization textures are mostly massive, disseminated, interbeds and banded zebra texture, brecciated, and colloform banding, and recrystallization textures. Additionally, recrystallization textures with cataclastic deformation and framboidal pyrite are observed in thin and polished sections In this study, a detailed lithogeochemical characterization of the stratigraphic units including the mineralized levels at Meskan was attempted. For this purpose a total of 439 drill core samples were analyzed for their major, minor, and trace element compositions (including total C and S) through ICP-ESMS and XRF methods. Based on their lithogeochemical characteristics, these samples were classified into five chemostratigraphic packages, in which Zn-Pb mineralization appears to be hosted by relatively pure carbonate rocks with low siliciclastic contents. Both petrography and XRD analysis of host rock samples demonstrate that dolomite is present only in small amounts within the altered and mineralized rocks. It occurs locally as a hydrothermal replacement phase within rocks exhibiting zebra-like textures. Dolomitization is not play a significant role in the Meskan succession. The ore host rocks exhibit a relatively lower amount of organic material compared to the surrounding strata. Lithogeochemical analysis including with carbon and sulfur analysis and provide critical insights into the geological and mineralogical characteristics of the Meskan deposit and establishment of relationships between rock geochemical signatures and mineralization. Contents of SiO2, Al2O3, K2O, TiO2, and most of the trace elements content are depleted in the main mineralized zone, whereas As, Cd, CaO, Fe2O3, Ge, Sb, Pb, Tl, and Zn values are enriched in these zone. Lack amount of HFSE may imply that these carbonates are mostly pure and depleted in silt amount. Cs is found to be enriched in pyrite, sphalerite, galena samples with respect to barren (but pyritic) zebra carbonates in main sulfide mineralization zone. The REE values demonstrate that the carbonates of Meskan deposit in main mineralized zone possess high Eu/ Eu* ratio (avg= 0.27), and low Ce/ Ce* ratio (avg= 1.78). The contrast values between Eu and Ce concludes that the characterisation of mineralized unit in Meskan deposit is controlled by detrital input and this unit is depleted in clastic sediments with respect to other units.

Subject Keywords

Meskan deposit, Hakkari, carbonate-hosted Pb-Zn, lithogeochemistry

URI

https://hdl.handle.net/11511/109823

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Graduate School of Natural and Applied Sciences, Thesis