Date

2005

Author

İmer, Ali

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With the closure of Neo-Tethys in the Early Tertiary, oceanic crustal material was accreted along the İzmir-Ankara-Erzincan Suture Zone. The Ankara mélange developed within this suture zone and contains Cretaceous ophiolitic fragments, some of which host significant Fe-Cu sulfide mineralization. Such mineralization is observed as massive to disseminated pyrite-chalcopyrite hosted by pillow to massive basalts in a dismembered and tectonically imbricated ophiolite block near Karaali, Ankara. Basaltic host rocks lack most of their primary mineral assemblages and textural relationships. As a consequence of greenschist-facies metamorphism and hydrothermal alteration, the basalts were strongly albitized and propylitized prior to late-stage argillic alteration, which is proximal to the main mineralized zone. Sulfide mineralization occurs in a massive sulfide lens and laterally extensive, 10-meter-thick zone of anastomosing quartz-sulfide veins. Other than pyrite and chalcopyrite, bornite, covellite and sphalerite also occur as minor sulfide phases, and the source of sulfur is determined to have been magmatic on the basis of 34S isotope analyses. A series of geochemical analyses suggest that the basaltic host rocks formed within a subduction-related tectonic setting, and the mineralization is thought to have formed during a medium-temperature hydrothermal event which was followed by another later period of low-temperature hydrothermal activity. Field, petrographical and geochemical evidence show that the Karaali Fe-Cu mineralization is genetically correlative with the Cyprus and Küre massive sulfide deposits, and may be classified as a أCyprus-typeؤ massive sulfide deposit.

Subject Keywords

Geology.

URI

http://etd.lib.metu.edu.tr/upload/3/12607049/index.pdf
https://hdl.handle.net/11511/15501

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Graduate School of Natural and Applied Sciences, Thesis