Geochemistry and genesis of the Kti-Teberda tungsten deposit, northern Caucasus: Evidence from the geochemistry and EPR spectroscopy of quartz and scheelite

Geochemistry and EPR spectra were examined in 35 scheelite and 29 quartz sa mples, which were taken from feldspar-quartz veins of the main mineralized zones trending roughly E-W and S-N at the four drift levels in the tungsten mineralization of the deposit over intervals of 1600 m updip and 700 m in vertical section. The investigations revealed distinct differences of quart z and scheelite of these mineralized zones. It was established that the var iations in the contents of extreme types of defects (Ti-H and Li-H) of Ti-b earing paramagnetic centers in quartz may be indicative of the acidity-alka linity regime of the mineral-formation environment. Based on this, we showe d that the quartz from the mineralized E-W-trending zones was formed in a l ess acid environment than that of the quartz from the S-N-trending zones. T he revealed increase in the Al3+ center content in quartz from the lower to upper levels are most likely to be related to an increase in the formation temperature of the ore-bearing quartz with depth. Many geochemical and EPR characteristics of quartz and scheelite from the mineralized zones, pegmat ites, and granites are similar. This may serve as additional evidence for a genetic relationship of the tungsten mineralization of deposit with the La te Paleozoic diorite-granite formation. Data on a regular increase in the A l3+, Ge3+ content in the quartz and a decrease in the isomorphic [MnF4](2-) admixture in the scheelite with depth are of interest for prospecting and exploration of the Kti-Teberda-type tungsten mineralization.