Geology, alteration, mineralization, and fluid inclusions of volcanic units from Bozhan exploration area, northeast of Neishabour

Document Type : Original Article

Authors

Abstract

Bozhan area is located in southernmost parts of the eastern Alborz mountain range in NE Iran and is part of the Binaloud structural zone. Geology of the study area include andesitic, trachyte, basaltic and basalt-andesite lavas, which are accompanied by intrusive, subvolcanic, and pyroclastic rocks. These rocks have undergone propylitic alteration. Mineralization occurs mainly along silicic and carbonate veinlets and has a variety of open space-filling, coliforms, brecciate, and vein-veinlets texture. Chalcopyrite is the most important and abundant sulfide mineral in these veins. Microthermometeric investagations were conducted on and in liquid-rich (L+V) fluids. Homogenization experiments revealed a temperature range of 195 to 262 ° C for the studied inclusion and salinity ranges from 10.61 to 14.67% NaCl equivalent. Reduction temperature and cooling are the most important factors in the deposition of metals along with the ore-fluid in the Bozhan exploration area. Meanwhile, mineralization in the Bozhan exploration area has a vein-veinlets trend that is consistent with existing fractures. Based on field observation, mineralogy, structure, texture and fluid inclusion, the Bozhan exploration area can be considered as epithermal vein systems.

Keywords


[1] Majidi B., “The ultrabasic lava flows of Mashhad, North East Iran.”, Geological Magazine 118 1 (1981) 49-58.

[2] Karimpour m. h., Farmer G. L., Stern C. R., “Geochronology, Radiogenic Isotope Geochemistry, and Petrogenesis of Sangbast Paleo-Tethys. (in Persian)", Iranian Journal of Crystallography and Mineralogy Vol. 17 No. 4 (2010) 702-715.

[3] Ghazi M., Hassanipak A.A., Tucker P.J., Mobasher K., “Geochemistry and Ar40- Ar39 ages of the Mashhad Ophiolite, NE Iran”, abstracts as: Eos. Trans. AGU, 82(47), Fall Meet. (2001).

[4] Alavi Mehdi, “Sedimentary and structural characteristics of the Paleo-Tethys remnants in northeastern Iran”, Geological Society of America Bulletin 103 8 (1991) 983-992.

[5] Alavi Mehdi, “Thrust tectonics of the Binaloud region; NE Iran”, Tectonics. 11 2 (1992) 360-370.

[6] Homam S. M., Rahimi B., “Mineral assemblages sequence of contact aureole of Mashhad granite.” (in Persian)", Iranian Journal of Crystallography and Mineralogy Vol. 18 No. 1 (2010) 125-134.

[7] Alberti A., Moazez. Z., “Plutonic and metamorphic rocks of the Mashhad area (northeastern Iran, Khorasan)”, Boll. Soc. Geol. Italy 93 (1974) 1157-1196.

[8] Samadi R., Valizadeh M. V., Mirnejad H., Kawabata H., “Geothermometry and Geobarometry of Metamorphic Rocks of Dehnow, (Northwest of Mashhad).” (in Persian)", Journal of Geoscience Vol 21 No. 84 (2012) 3-14

[9] Mirnejad H., Obeid M., Hasanandzadeh J., “petrogenesis of Mashhad granitoids: An insight into the geodynamic history of the Paleo-Tethys in northeast of Iran”, Lithos Vol. 170 No. 1 (2013) 105-116

[10] Pourlatifi A., “Geological Map of Torghabeh 1:100000”, Geological survey of Iran 2001.

[11] Nabavi M.H., “A Preface to Iran's Geology.” Geology Survey & Mineral Exploration of Iran, (1976) 109 P.

[12] Steele-MacInnis M., Lecumberri-Sanchez P., Bodnar R.J., “Hokieflincs-H2O- NaCl: A Microsoft Excel spreadsheet for interpreting microthermometric data from fluid inclusions based on the PVTX properties of H2O–NaCl”, Computer in Geosciences, 49. 334–337.

[13] Lecumberri-Sanchez P., Steel-MacInnis M., Bodnar R.J., “A numerical model to estimate trapping conditions of fluid inclusions that homogenize by halite disappearance”, Geochimica et Cosmochimica Acta 1992, 14-22.

[14] Bodnar R. J., Vityk M. O., “Interpretation of micro-thermometric data for H2O–NaCl fluid inclusions. In: De Vivo, B. and Frezzotti, M.L. (Eds.), Fluid Inclusions in Minerals: Methods and Applications. Short Course of the Working Group, Siena,” 1994 117–130.

[15] Sorby H. C., “On the microscopic structure of crystals indicating the origin of minerals and rocks,” Journal of Geological Society, London, 14. 453-500.

[16] Wiesheu R., Hein U. F., “The history of fluid inclusion studies. In: Fritscher, B. and Henderson, F. (Eds.), Toward a History of Mineralogy, Petrology, and Geochemistry,” Institute für Geschichte der Naturwissenschaften, Munich, 1998 309–325.

[17] Whitney D.L., Evans B.W., “Abbreviations for Names of Rock-Forming Minerals”, American Mineralogist, 95 (2010) 185-187.

[18] Oakes C.S., Bodnar R.J., Simonson J.M., “The system NaCl–CaCl2–H2O: I. The ice liqiudus at 1 atm total pressure”, Geochim. Cosmochim. Acta 1990 54, 603–610.

[19] Shepherd T. J., Rankin A. H., Alderton D. H. M., “A practical guide to fluid inclusion studies.” Blackie, Glasgow, 1985 239p.

[20] Wilkinson J.J., “Fluid inclusions in hydrothermal ore deposits.”, Lithos 2001 55, 229–272.

[21] Simmons S. F., White N. C., John D. A., “Geological characteristics of epithermal precious and base metal deposits. In: Hedenquist, J.W., Thompson, J.F.H., Goldfarb, J.R. and Richards, J.P.) Eds.(100th Anniversary Volume.”, Economic Geology, 2005 485–522.