Origin and nature of the mineralizing fluids of thrust zone fluorites in Çelikhan (Adiyaman, Eastern Turkey): A geochemical approach

Abstract

The Çelikhan fluorite mineralization is concentrated in the thrust zone between the Pinarbasi Formation, which forms the hanging wall, and the Kalecik Limestone foot wall. Fluorite occurs as fracture fills in the thrust zone and as replacement of the foot wall. The wall rock alteration consists of calcite, barite, quartz and kaolinite. The total REE contents of the country rocks, especially the mica- and calc-schists of the Pinarbasi formation at 519 ppm, are higher than those of fluorites. The chondrite normalized REE patterns of country rock and fluorites display generally identical trends. However, fluorite patterns show positive Eu and negative Ce anomaly indicative of low temperature and high fo2 conditions. Cross plots of the Tb/Ca – Tb/La, (La/Yb)n – (Tb/Yb)n and (La/Yb)n (Eu/Eu*)n ratios of the fluorites indicate deposition by low temperature hydrothermal waters. The REE and F were probably leached from the Pinarbasi Formation by the mineralizing solutions. The mineralizing fluids are probably meteoric and formation waters heated at depth along the thrust zone by the natural thermal gradient and/or formation waters heated and mobilized by thrusting.