Sulfur, Carbon and Oxygen Isotope Variations of Sulfide and Carbonate in Arghash Gold Prospect, Southwest Neishabour, Northeastern Iran

Ashrafpour, E.; M. Ansdell, K.; Alirezaei, S.

doi:10.22071/gsj.2009.57389

Document Type : Original Research Paper

Authors

¹ Department of Geology, University of Shahid Beheshti, Tehran, Iran

² Department of Geology, University of Saskatchewan, Canada

https://doi.org/10.22071/gsj.2009.57389

Abstract

Arghash gold district includes five gold-bearing vein systems, (Au-ItoAu-V) and one antimony-rich vein hosted by intermediate to silicic volcanic rocks, tuffs, granite, and diorite. Pyrite is the main sulfide mineral consisting of four generations (Py-ItoPy-IV). Py-I toIII are intimately associated with gold; however, Py-IV is barren. The δ³⁴S values of pyrites in conventional bulk analyses fall into two groups, one highly enriched in ³⁴S (δ³⁴S= +9.3 to +21.8‰), and the other less enriched to slightly depleted in ³⁴S (δ³⁴S= +5.1 to -4.3‰). In-situ laser probe experiments were carried out to characterize various generations of pyrite. The results indicate a relatively narrow range for Py-I to Py-III (δ³⁴S= -5.8 to +0.1‰) consistent with a magmatic source for sulfur. Py-IV is highly enriched (δ³⁴S= +8.9 to +23.7‰), implying contributions of sulfur from sources enriched in ³⁴S, like evaporites. The high δ³⁴S values in the enriched group can be attributed to a significant occurrence of Py-IV in this group.
The δ³⁴S values of two stibnites from Sb ore (-18.8 and -14.4‰) suggest a different sulfur, and possibly metal source, and/or radical changes in the physicochemical conditions of the fluid during deposition of stibnite. Metasedimentary basement rocks could contribute sulfur and metal to the circulating fluids. δ¹³C_PDB values of vein calcites are near 1 per mil suggesting a sedimentary source for carbon. Carbonate units and interlayers in the area are a suitable source for CO₂in the ore fluids. The stable isotope data suggest that hydrothermal fluids experienced a complex history of water/rock interaction and that ore components, were derived, at least partly, from country rocks.

Keywords

20.1001.1.10237429.1387.18.70.18.8

References

References

Ahmad M., Solomon M. & Walshe J.L., 1987- Mineralogical and geochemical studies of the Emperor gold telluride deposit, Fiji, Economic Geology, 82: 345-370.

Camus F., Boric R., Skewes M.A., Castelli J.C., Reichhard E. & Mestre A., 1991- Geologic, structural, and fluid inclusion studies of El Bronce epithermal vein system, Petorca, Central Chile, Economic Geology, 86: 1317-1345.

Fallick A.E., McConville P., Boyce A.J., Burgess R. & Kelley S.P., 1992- Laser microprobe stable isotope measurements on geological materials: some experimental considerations (with special reference to (³⁴S in sulfides)), Chemical Geology, 101: 53-61.

Geological Survey of Iran, 1992- Geological map of Torbat Heidarieh (scale 1:250,000).

Germann K., Lüder V., Banks D.A., Simon K. & Hoefs J., 2003- Late Hercynian polymetallic vein-type base-metal mineralization in the Iberian Pyrite Belt: fluid-inclusion and stable-isotope geochemistry (S-O-H-Cl), Mineralium Deposita, 38: 953-967.

Hoefs J., 2004- Stable Isotope Geochemistry, Springer-Verlog, Berlin, 244 p.

John D., Hofstra A.H., Fleck R.J., Brummer J.E. & Saderholm E.C., 2003- Geologic setting and genesis of the Mule Canyon low sulfidation epithermal gold-silver deposit, North-Central Nevada, Economic Geology, 98: 425-463.

Keivanfar M. & Asgari A., 2000- Explanatory text of geological map of Arghash district (scale 1:5000): Geological Survey of Iran, 81 p, (in Persian).

Kelley S.P. & Fallick A.E., 1990- High precision spatially resolved analysis of d34S in sulfides using a laser extraction technique, Geochimica et Cosmochimca Acta, 54: 883-888.

Lensch G., Mihm A. & Alavi-Tehrani N., 1977- Petrography and geology of the ophiolite belt north of Sabzevar/Khorasan (Iran), Neues Jahrbuch Fur Geologie un Palaontologie Monatshefte, 131: 156-178.

Lindenberge H.G., Gorler K. & Ibbeken H., 1983- Stratigraphy, structure and orogenic evolution of the Sabzevar zone in the area of Oryan (Khorasan, NEIran), Geological Survey of Iran Report 51, p. 119-143.

McCrea J.M., 1950- On the isotopic chemistry of carbonates and a paleotemperature scale, Journal of Chem. Physics, 18: 849-857.

McKibben M.A. & Eldridge C.S., 1990- Radical sulfur isotope zonation in pyrite accompanying boiling and epithermal gold deposition: a SHRIMP study of the Valles Caldera, New Mexico, Economic Geology, 85: 1917-1925.

Ohmoto H. & Goldhaber M.B., 1997- Sulfur and carbon isotopes. In: Barnes H.L. (eds.) Geochemistry of hydrothermal ore deposits, John Wiley and Sons, pp. 517-611.

Ohmoto H. & Rye R.O., 1979- Isotopes of sulfur and carbon. In: Barnes H.L. (eds.) Geochemistry of Hydrothermal Ore Deposits, John Wiley and Sons, pp. 509-567.

Ohmoto H., 1972- Systematics of sulfur and carbon isotopes in hydrothermal ore deposits, Economic Geology, 67: 551-578.

Ronacher E., Richards J.P., Reed M.H., Bray C.J., Spooner E.T.C. & Adams P.D., 2004- Characteristics and evolution of the hydrothermal fluid in the north zone high-grade area, Porgera gold prospect, Papua New Guinea, Economic Geology, 99: 843-867.

Sengor A.M.C., 1990- A new model for the Late Paleozoic-Mesozoic tectonic evolution of Iran and implications for Oman. In: Robertson, A.H.F., Searle, M.P., Ries, A.C., (eds.) The Geology and Tectonics of the Oman Region, Geological Society of London Special Publication 49, pp. 797-831.

Shelton K.L., So C.S., Haeussler G.T., Chi S.J. & Lee K.Y., 1990- Geochemical studies of the Tongyoung gold-silver deposits, Republic of Korea: Evidence of meteoric water dominance in a Te-bearing epithermal system, Economic Geology, 85: 1114-1132.

So C.S., Chi S.J., Shelton K.L. & Skinner B.J., 1985- Copper-bearing hydrothermal vein deposits in the Gyeongsang basin, Republic of Korea, Economic Geology, 80: 43-56.

Spies O., Lensch G. & Mihm A., 1983- Geochemistry of the post-ophiolitic Tertiary volcanics between Sabzavar and Quchan/NE-Iran: Geological Survey of Iran, Report No.51, p. 247-267.

Thiersch P.C., Williams-Jones A.E. & Clark J.R., 1997- Epithermal mineralization and ore controls of the Shasta Au-Ag deposit, Toodoggone district, British Columbia, Canada, Mineralium Deposita, 32: 44-57.

TOZCO, 2001- Regional geological map of Arghash area, Geological Survey of Iran.

Wagner T., Boyce A.J. & Fallick A.E., 2002- Laser combustion analysis of δ³⁴S of sulfosalt minerals: determination of the fractionation systematics and some crystal-chemical considerations, Geochimica et Cosmochimica Acta, 66: 2855-2863.

Scientific Quarterly Journal of Geosciences

Sulfur, Carbon and Oxygen Isotope Variations of Sulfide and Carbonate in Arghash Gold Prospect, Southwest Neishabour, Northeastern Iran

References

References

Volume 18, Issue 70
February 2009
Pages 173-183

Sulfur, Carbon and Oxygen Isotope Variations of Sulfide and Carbonate in Arghash Gold Prospect, Southwest Neishabour, Northeastern Iran

References

References

Volume 18, Issue 70February 2009Pages 173-183

Volume 18, Issue 70
February 2009
Pages 173-183