Geology of the Karakuz iron mine and vicinity, Hekimhan district, Turkey

Abstract

The Karakuz mine area located 17 km northwest of the town of Hekimhan in central Turkey was investigated as part of the MTA-USGS Mineral Exploration and Training Project. The fieldwork consisted of geologic mapping supplemented by a magnetometer survey and trenching. The Karakuz mine has been in operation for the past ten years and produced 170,000 tons of iron ore in 1968. The rocks of the area are mafic and ultramafic rocks, limestone, and trachyte intruded by syenite (Cretaceous?), and an Eocene post-intrusive(?) sedimentary sequence. The mafic rocks and the trachyte were altered and mineralized as a result of the syenite(?) intrusion. The mafic rocks were metasomatically altered and the trachyte was partly silicified. Iron oxide minerals are present in the trachyte as irregular replacement bodies and veins and in the metasomatized mafic rocks as veins. A major structure which channeled the intrusion and iron oxide minerals is believed to underlie the area. Steeply dipping fractures trending about N. 80 ° E. and N. 10 ° W. acted as controls on the mineralization. A series of recent post-mineral faults, erosion, and weathering have produced the present landscape. The principal iron deposit is at the Karakuz mine where a central high-grade core is surrounded by low-grade material. The changes in grade reflect changes in the degree of replacement of the trachyte by iron oxides. The minerals are dominantly hematite, but magnetite and limonite are also present. East and west of the mine there are a series of low-grade replacement bodies and veins as well as iron boulder fields. A series of magnetic anomalies are present along the entire 4 km length of the area. The anomalies are interpreted to be caused principally by magnetite-bearing surface boulders and near-surface veins. Only a small part of some of the anomalies may be due to buried deposits of magnetite. The Karakuz mine has a remaining productive life of about 3 years unless low-grade material is mined. This may be feasible if the low-grade is concentrated at the mine. 'Additional exploration of the area is recommended with emphasis on a gravity survey and diamond drilling. Also, an investigation to determine the technical and economic feasibility of utilizing the low-grade material is recommended.