The Magnetite-apatite Ore Deposit of Pınarbaşı (Bulam), Adıyaman Province, South-eastern Turkey

Abstract

The Precambrian (Pütürge Metamorphites), the Eocene (Maden Complex), the Permo-Carboniferous (Malatya Metamorphites), the tertiary conglomerates and the alluvial formation all crop out in the vicinity of the magnetite-apatite ore deposits of Pınarbaşı. The Malatya Metamorphites, which are products of regional metamorphism in ore deposits, are in an area thrust over the Maden Complex. From bottom to top, the area includes chlorite schists, calc schists and recrystallized limestone. Abundant rock-forming minerals in the area include chlorite, mica, quartz and calcite. The existing mineral facies indicate that ore deposits in the area metamorphosed as at least one regional barrow type in the greenschist facies at 400°C temperature and 0.4 MPa pressure, and they depend on contact and retrograde metamorphism. As a result of this process, the area’s ore deposits are highly folded and faulted. The ores consist of magnetite, hematite (specularite) and goethite. The important gangue minerals are fluorapatite, quartz, chlorite and micas. Geologic and geochemistry data indicate that the original rocks of the recent chlorite schist were pelitic sediments. Levels of the 18O isotope showed that the formation temperature varied between 282-372°C. This temperature corresponds to the beginning of the greenschist facies temperature of the regional metamorphism. Hydrogen isotope analysis reflects the sedimentary rock’s value and supports the geochemistry diagnosis. The radiometric age determination indicated two different age values, 66 and 48 Ma. The older age of 66 Ma explains the metamorphosis that evolved during the ophiolite development. The younger age of 48 Ma is interpreted as a second metamorphism, retrograde metamorphism or tectonic movement age. The Pınarbaşı ore deposit is described as a metamorphosed metasedimentary magnetite-apatite ore deposit. Similar magnetite-apatite ore deposits is the Avnik deposits in Turkey. Determined proved and inferred reserves amount to 78 Mt with 35.07wt % Fe and 1.57wt % P2O5 content. The operation of the ore is currently planed for 2016.