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

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 δ 34 S values for vent chimneys in the eastern Pontide VMS deposits is -2.7 to 6.5 per mil. Sulfide δ 34 S values show narrow variation in the Lahanos, Killik, and Kutlular deposits, but wider variation in the Kızılkaya and Çayeli deposits. The δ 34 S 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 δ 34 S 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 δ 34 S values of sulfide minerals are similar for different deposits within the same region. Variations in the δ 34 S 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 δ 34 S 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.

Review of Late Cretaceous volcanogenic massive sulfide mineralization in the Eastern Pontides, NE Turkey

“…Generalized stratigraphic column for the eastern Pontides, NE Turkey, with the positions of VMS-type deposits. The stratigraphic range of VMS ores is also shown (compiled from Güven, 1993;Konak et al, 2001;Kurt et al, 2005;Revan, 2010;Revan et al, 2016;Alan et al, 2016;Kandemir et al, 2019). .…”

“…These recent values were considered to represent a reduced seawater sulfate origin with variable contributions of deep-seated sulfur leached from the host rock during hydrothermal circulation (Revan et al, 2016).…”

“…Thus, biogenic reduction is not regarded as a major sulfide-generating process for the Pontide deposits. Some researchers(Revan et al, 2016) suggest only episodic participation of biogenic reduced sulfide as a source of sulfur in the Pontide deposits.…”

Mineralogy and geochemistry of metalliferous sedimentary rocks from the Upper Cretaceous VMS deposits of the Eastern Pontides (NE Turkey)

“…However, it is relatively much easier to find traces of primary features in nonmetamorphosed terrains and in areas where only slight deformation has taken place. Unlike those in many VMS districts, the primary features of the VMS deposits in the Eastern Pontide district have been largely preserved due to the nonmetamorphosed nature of the region (Çiftçi, 2000;Revan et al, 2016). It is much easier to find traces of ore-bearing sedimentary facies in the deposits of this belt in comparison with other VMS districts.…”

“…Summary stratigraphic column for the VMS-hosting Upper Cretaceous volcanic rocks and the position of VMS-type massive sulfide deposits of the Eastern Pontides (modified fromRevan et al, 2016).…”