Sulfur isotope study of vent chimneys from Upper Cretaceous volcanogenic massive sulfide deposits of the eastern Pontide metallogenic belt, NE Turkey

Authors: MUSTAFA KEMAL REVAN, VALERİY V MASLENNIKOV, YURDAL GENÇ, OKAN DELİBAŞ, SVETLANA P MASLENNIKOVA, SERGEY A SADYKOV

Abstract: We obtained sulfur isotope analysis results of sulfide samples from hydrothermal vent chimneys of the eastern Pontide volcanogenic massive sulfide (VMS) deposits. The total range of δ³⁴S values for vent chimneys in the eastern Pontide VMS deposits is -2.7 to 6.5 per mil. Sulfide Δ³⁴S values show narrow variation in the Lahanos, Killik, and Kutlular deposits, but wider variation in the Kızılkaya and Çayeli deposits. The δ³⁴S values of sulfides in Çayeli chimney samples gave a slightly higher range than the other Pontide chimney samples. In some samples, a rough isotopic zonation pattern was observed throughout chimney zones. Variations in δ³⁴S values of sulfides within chimney walls were probably caused by chemical reactions of reprecipitation and replacement between vent fluids and earlier sulfide minerals in the chimney. Ranges of Δ³⁴S values of sulfide minerals are similar for different deposits within the same region. Variations in the δ³⁴S values of the Pontide deposits appear to be geographic rather than stratigraphic. The sulfur isotope values of the deposits have a narrow compositional range, indicative of a fairly specific origin. Although "deep-seated" sulfur may be a potential source in the Pontide district, a significant contribution of seawater sulfate cannot be ruled out. The δ³⁴S values of selected samples from Pontide vent chimneys are within the range of sulfur values obtained from Phanerozoic VMS deposits. The range is similar to, but slightly broader than, the range of values reported for modern vent chimneys and ancient vent chimneys from the Yaman-Kasy deposit.

Keywords: Eastern Pontide, hydrothermal chimneys, sulfur isotopes, volcanogenic massive sulfide

Full Text: PDF