Mineralization and hydrothermal alteration of the Tajroud vein system, south of Neyshabour

زمین شناسی اقتصادی

Article 6, Volume 5, Issue 2 - Serial Number 9, January 2014, Pages 325-339   

Document Type: Research Article

DOI: 10.22067/econg.v5i2.31886

Authors

Mohsen Alikhani; Gholam Hossein Shamanian^* ; Mohammad Jafari Zanglanlou

Golestan

Abstract

The Tajroud vein system is located 190 km southwest of Mashhad, and in the southern part of the Sabzevar zone. The vein host rocks consist of Eocene intermediate to silicic volcanic rocks. The mineralization occurs as open space filling, taking place as veins, veinlets and hydrothermal breccias. Based on field geology and textural evidence, three main stages of mineralization were identified. Stage I mainly contains quartz, pyrite, chalcopyrite and magnetite. Stage II, which has the same mineral assemblage as stage I, is the most important stage in terms of volume. Finally, stage III is characterized by repetitive quartz and calcite banding with negligible amounts of sulfide minerals. Hydrothermal alteration is developed around the veins and tends to be more intense in the vicinity of the veins. The plot of the Ishikawa alteration index (AI) versus chlorite-carbonate-pyrite index (CCPI), known as alteration box plot, displays three main alteration trends. The hydrothermal alteration assemblage of quartz, adularia, chlorite, illite, calcite, and epidote that envelops the Tajroud vein system formed from the upwelling of near-neutral to weakly alkaline hydrothermal solutions. The mineralogic, alteration and geochemical characteristics of the studied area and comparison with epithermal ore deposits indicate that the Tajroud vein system represents an epithermal system of low-sulfidation type.

Keywords

Epithermal; hydrothermal alteration; Alteration index; Low-sulfidation; Tajroud

References

[1] Simmons S. F., White N. C., and John D. A., "Geological characteristics of epithermal precious and base metal deposits", Economic Geology 100th Anniversary )2005 (485-522.

[2] Lagat J., “Hydrothermal Altreation Mineralogy in Geothermal Fields with Case Exampels from Olkaria Domes Geothermal Field, Kenia, Presented at Short Course II on Surface Exploration for Geothermal Resources, organized by UNU-GTP and KenGen”, at Lake Naivasha, Kenya (2007) 2-17.

[3] Heaker C. A., Van der meer F. D., “Characterization of Hydrothermal Alteration in Mount Berecha Area of Main Ethiopian Rift using Hyperspectral Data”, Oluwadebi Ayomiposi Grace (2011) 1-75.

[4] Simmons S. E., Browne P., “Hydrothermal minerals and precious metals in the Broadland-Ohaaki Geothermal system; Implication for understanding low- sulfidation epithermal environments”, Economic Geology 95 (2000) 971-1000.

[5] Mauk J. L., Simpson M., “Geochemistry and stable isotope composition of altered rocks at the Golden Cross epithermal Au-Ag deposit, New Zealand”, Economic Geology 102 (2007) 841-871.

[6] Warren I., Simmons S. F., Mauk J. L., “Whole rock geochemical techniques for evaluating hydrothermal alteration, mass changes, and compositional with epithermal Au-Ag mineralization”, Economic Geology 102 (2007) 923-948

[7] White N. C., Hedenquist J. W., “Epithermal Gold Deposits: Styles, Characteristics and Exploration”, Society of Economic Geologists 23 (1995) 9-13.

[8] Hedenquist J. W., Arribas R. A., Urien E. G. “Exploration for Epitermal Gold Deposite”, Society of Economic Geologist 13 (2000) 245-277.

[9] Large R. R., Gemmell J. B., Paulick H., Huston D., “The alteration box plot: a simple approach to understanding the relationship between alteration mineralogy and lithogeochemistry associated with VHMS deposite”, Economic Geology 96 (2001) 957-972.

[10] Gemmell J. B., “Hydrothermal Alteration Associated with the Gosowong Epithermal Au-Ag Deposit, Halmahera, Indonesia: Mineralogy, Geochemistry, and Exploration Implications”, Society of Economic Geologists 102 (2007) 893–922.

[11] Gemmell J. B., Large R. R., “Stringer system and alteration zones underlying the Hellyer volcanic-hosted massive sulfide deposit, Tasmanian, Australian”, Economic Ggeology 87 (1992) 620-649.

[12] نادری‌میقان ن.، شجائی کاوه ن.، بهرمند، م.، خریری ف.، "نقشه‌ زمین‌شناسی شامکان (مقیاس1:100000)"، سازمان زمین‌شناسی و اکتشافات معدنی کشور، (1377).

[13] جعفری م.، سدید س.، "گزارش اکتشافات ژئوشیمیایی سیستماتیک 1:25000 منطقه تجرود"، سازمان زمین‌شناسی و اکتشافات معدنی منطقه شمال‌شرق کشور، (1389)، منتشر نشده، 165 ص.

[14] Edgar H. B., Rollin E. F., “Selective staining of k-feldespar and plagioclase on rock slabs and thin sections”, the American Mineralogist 45 (1960) 1020-1025.

[15] Lensch G., “Major element geochemistry of the ophiolites north of Sabzevar (Iran)”, Neues Jahrbuch Fur Geologie und Palantologi, Monatshefte 7 (1979) 415-447.

[16] Lensch G., Mihm A., Alavi-Tehrani N., “Petrography and geology of the ophiolite belt north of Sabzevar/Khorasan (Iran)”, Neues Jahrbuch Fur Mineralogie, Abhandlungen 131 (1977) 156-178.

[17] Spices O., Lench G., Mihm A., “Geochemistry of the post –ophiolitic Tertiary volcanic between Sabzevar and Quchan/NE-Iran”, Geological survey of Iran 51 (1983) 247-267.

[18] Shojaat B., Hassanipak A. A., Mobasher K., Ghazi A. M., “Petrology, geochemistry and tectonics of the Sabzevar ophiolite, North Central Iran”, Journal of Asian Earth Sciences 21, Issue 9 (2003) 1053-1067.

[19] De Ronde C.E.J., Blattner P., “Hydrothermal Alteration, Stable Isotopes, and Fluid Inclusions of the Golden Cross Epithermal Gold-Silver Deposit, Waihi, New Zealand”, Society of Economic Geologists 83 (1988) 895-917.

[20] Albinson T., Norman D. I., Cole D., Chomiak B. “Controls on formation of low-sulfidation epithermal deposits in Mexico: Constraints from fluide inclusion and stable isotope data” , Society of Economic Geology 8 (2001) 1-32.

[21] Camprubi A, Ferrari L., Cosca M. A., Cardellach E., Canals A., “Ages of Epithermal Deposits in Mexico: Regional Significance and Links with the Evolution of Tertiary Volcanism”, Economic Geology 98 (2003) 1029–1037.

[22] زراسوندی ع.، "اطلس دگرسانی: راهنمای مطالعات صحرایی و میکروسکپی برای کانیهای دگرسانی گرمابی"، انتشارات دانشگاه شهید چمران، (1386) 121 ص.

[23] احمدی م. ح.، "دگرسانی گرمابی و کانی‌سازی فلزات پایه و گرانبها در منطقه مطرآباد، جنوب غربی بجستان: بر پایه داده‌های کانی‌شناسی، زمین‌شیمیایی و سنجش از دور"، پایان‌نامه کارشناسی ارشد، منتشر نشده، (1390)، 120 ص.

[24] Ishikava y., Sawaguchi T., Iway S., Horiuchi M., “Delineation of prospecting targets for Kuroko deposits based on modes of volcanism of underling dasite and alteration halos”, Mining Geology 26 (1976) 105-117 (in Japanese with English abs).

[25] Simmons S. F., Browne P. R. L., “Mineralogic, alteration and fluid inclusion studies of epithermal gold-bearing veins at the Mt. Muro prospect, Central Kalimantan (Borneo), Indonesia”, Journal of Geochemical Exploration 35 (1990) 63–104.