Geology and formation of Nevruztepe Fe-Cu skarn mineralization (Kayseri-Turkey)

Abstract

The Nevruztepe iron-copper prospect is a skarn near Yeşilhisar (Kayseri). It has been overlookedas a potential producer of copper. The skarn was generated in Permian to Jurassic carbonate rocksby the Eocene Yahyalı granitic pluton. Lithologic units, including skarns, dip about 15 degreessouthward. Skarns are both prograde (garnet and diopside) and retrograde (epidote); both exoskarnand endoskarn exist. Most of the magnetite is in a quartz-sulfide stage in retrograde skarn that iscut by veins and lenses containing quartz-pyrite-chalcopyrite. Granite and mineralized skarn arerare at the surface. From 2013 to 2015, 31 drill holes (totaling 6.178,5 m) encountered skarn to adepth of 450 m. Mineralized zones vary from 1,2 to 54,7 m thick. Fe mean grade ranges from 12%to 49%; mean copper grades vary from 10 to 4650 ppm. The deposit contains 5.096.788 tonnes ofmineralized material. Microscopy on samples of drill core shows that the ore minerals are primarilymagnetite, hematite, and chalcopyrite. Some magnetite is altered to hematite. Experiments showthat with grinding to 100 microns the iron can be beneficiated to 66%. Waste from separation ofthe magnetite is 0.16 to 0.19% Cu; with flotation this was beneficiated to 19% Cu.