||Prof. Dr. Mehmet ARSLAN|
||Graduate School of Natural and Applied Sciences|
||Karadeniz Technical University, Turkey||
|Title of the Thesis:
||NATURE AND ORIGIN of HYDROTHERMAL ALTERATION of THE KUTLULAR (SÜRMENE-TRABZON) MASSIVE SULPHIDE DEPOSIT, USING CLAY MINERALOGY, GEOCHEMISTRY and STABLE ISOTOPES|
|Number of Pages:
The Late Cretaceous aged volcanogenic massive sulfide deposits and accompanying hydrothermal alteration are widespread in the Eastern Pontide. One of these, the Kutlular (Sürmene, Trabzon) massive sulphide deposit is surrounded by the Cretaceous aged and hydrothermally altered mafic-felsic subvolcanics and volcanics. The footwall and hanging-wall rocks are dacitic pyroclastics and basalt, basaltic andesites and their pyroclastics, respectively. In the light of petrographic, whole-rock and clay mineralogy (XRD, SEM, DTA-TG) studies, hydrothermal alteration zones are well developed and represented by silicification-pyrite-illite zone, illite-silicification zone, illite/smectites-silicification zone, smectite zone accompanying kaolenite zone in the dacitic pyroclastics, and additionally, chlorite zone in the mafic volcanics.
The Kutlular volcanics are tholeiitic-transitional and calc-alkaline in character. The trace element patterns show considerable K, Rb, Ba and Th enrichment and Sr, Ti and P depletion relative to N-MORB. Chondrite-normalized REE patterns are pronounced by positive and negative Eu and Ce anomalies, indicating alteration by sulphide-sulfate forming fluids. Based on mineral (MINSQ), mass transfer and factor analysis data, the footwall- and hanging-wall alteration zones show systematic changes with increasing proximity to the ore; Na and Ca depletion, K and Si enrichment, increases in alteration index and chlorite-carbonate-pyrite index and decreases in 18O and 34S. The chlorite and 18O geothermometry give temperatures; 184-250°C for chlorite, 77-118°C for kaolenite, 87-134°C for smectite, 121-186°C for illite/smectite and 149-323°C for illite. 34S values vary 3.6-4.8 for pyritic ore and 4.4-6 for whole rock. K-Ar dating on illite/smectites (75-91.3 Ma) indicates a complex illitization process by the beginning of Campanian time.