رهیافتی بر شکل‌گیری کانسار مس ماهور، جنوب غرب نهبندان، بر پایه بررسی‌های کانی-شناسی، میانبارهای سیال و ایزوتوپ‌های گوگرد

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه لرستان

2 دانشگاه فردوسی مشهد

چکیده

منطقه ماهور در 135 کیلومتری جنوب غرب نهبندان در استان خراسان جنوبی در بخش مرکزی کمربند آتشفشانی-ماگمایی قطعه لوت واقع است. نفوذ یک توده گرانیتوئیدی با ترکیب دیوریت، کوارتز دیوریت، کوارتز مونزو دیوریت و کوارتز مونزونیتی با سن الیگوسن  به درون سنگ­های آتشفشانی منطقه با سن پالئوسن- ائوسن منجر به دگرسانی و کانی­سازی شده است. پهنه­­های دگرسانی منطقه شامل آرژیلی (کانی های رسی)، پروپلیتی (کلریت، سریسیت، کلسیت و اپیدوت)، فیلی (کوارتز، سریسیت و پیریت) و سیلیسی هستند. رخداد کانی­سازی به صورت افشان و رگچه­ای  بوده و شامل پیریت، مگنتیت، کالکوپیریت، اسفالریت، گالن، آرسنوپیریت، کوبانیت، کوولیت، تتراهدریت، جیمسونیت و استیبنیت است. بر اساس روابط قطع­شدگی بین رگچه­ها، دو نوع رگچه کوارتز + اسفالریت + پیریت  ± کالکوپیریت (رگچه­های نوع 1) و کوارتز + پیریت + کالکوپیریت  ± اسفالریت (رگچه­های نوع 2) در بخش­های عمقی منطقه شناسایی شده است. سیال­های درگیر در رگچه­های نوع 1 و 2 به ترتیب دارای شوری 8/6 تا 2/21 و 9/7 تا 2/20 درصد وزنی معادل NaCl  و دمای همگن­شدگی 315 تا 575 و 177 تا 454 درجه سانتیگراد هستند. یافته­های ریزدماسنجی  بیانگر دگرگونی سیال کانه­ساز طی رخدادهای جوشش و آمیختگی سیال­های ماگمایی با آب­های جوی است. مقدار  δ34Sپیریت و کالکوپیریت 15/3-8/1 درهزار بیانگر خاستگاه ماگمایی گوگرد است. نتایج بررسی­های زمین­شناسی، دگرسانی، کانی­سازی، سیال­های درگیر و ایزوتوپ­های پایدار گویای رخداد کانی­سازی سامانه پورفیری در منطقه ماهور است.    

کلیدواژه‌ها


عنوان مقاله [English]

An approach to the genesis of Mahoor copper deposit, southwest of Nehbandan, based on mineralogy, fluid inclusions and sulfur isotopes studies

نویسندگان [English]

  • Almasi 1
  • Miri Beydokhti 2
  • Karimpour 2
  • Mazaheri 2
1
2
چکیده [English]

The Mahoor area is located about 135 km southwest of Nehbandan city, Khorasan Jonoobi Province, and in the central Lut block volcano-plutonic belt.  The intrusion of an Oligocene granitoid pluton with diorite, quartz diorite, quartz monzodiorite, and quartz monzonite into Paleocene-Eocene volcanic rocks that led to alteration and mineralization. Hydrothermal alteration zones consist of argillic (clay minerals), propylitic (chlorite, sericite, calcite, epidote), phyllic (quartz, sericite, pyrite), and silicification. The main ore minerals include sphalerite, chalcopyrite, magnetite, pyrite, stibnite, tetrahedrite, jamesonite, covellite, cubanite, arsenopyrite and galena, occurring as veinlets and disseminations. According to crosscutting relationships, two type of veinlet have been identified at deep levels of Mahoor deposit. Type (1) Quartz + sphalerite+ pyrite ± chalcopyrite, and type (2) Quartz +pyrite +chalcopyrite± sphalerite. The homogenization temperature and salinity of fluid inclusions in type 1 of veinlets range from 315 to 575°C and 6.8 to 21.2 wt. % equivalent NaCl, respectively. Fluid inclusions in type 2 of veinlets show homogenization temperature and salinity from 177 to 454°C and 7.9 to 20.2 wt. % equivalents NaCl, respectively. The microthermometric data indicate that the ore forming hydrothermal solution evolved through boiling events and mixing of magmatic fluids with meteoric waters. Sulfur isotopic values of pyrite and chalcopyrite vary from 1.8‰ to 3.15‰, suggesting that S was derived from a magmatic source. Geology, alteration, mineralization, fluid inclusion, and stable isotope studies indicate that mineralization in Mahoor area occurred as porphyry system.

کلیدواژه‌ها [English]

  • Mineralization
  • alteration
  • fluid inclusions
  • sulfur isotope
  • Mahoor
  • Lut block
[1] Esmaeily D., Nedelec A., Valizadeh M.V., Moore F., Cotton J., "Petrology of the Jurassic Shah-Kuh granite (eastern Iran), with reference to tin mineralization", Journal of Asian Earth Sciences 25(2005) 961-980.

[2] Karimpour M. H., Stern C. R., Farmer L., Saadat S., "Malekezadeh A. Review of age, Rb-Sr geochemistry and petrogenesis of Jurassic to Quaternary igneous rocks in Lut Block, Eastern Iran", JGeope 1 (2011) 19-36.

[3] Stocklin J., ″Structural history and tectonics of Iran: a review", American Association of Petroleum Geologists Bulletin 52 (1968) 1229–1258.

[4] Mirzaei Rayeni R., Ahmadi A., Mirnejad H., ″Mineralogy and fluid inclusion studies in Mahour copper deposit, East of Lut block, central Iran (in Persian)″, Iranian Journal of Crystallography and Mineralogy 20 (2012), 307-318.

[5] M Esform., ″Geochemistry and paragenesis sequence of minerals in Mahoor poly metal deposit, West of Nehbandan (East of Iran), (in Persian)″, Msc thesis, Sistan and Balochestan University(2011).

[6] Esform M., Biabangard B., Bomeri M., Zarinkob M.H., Mahram M., Ebrahimi., V., ″Geochemistry and petrology of volcanic rocks at Mahoor Cu deposit, NW Nehbandan(in Persian)″,Iranian Journal of Crystallography and Mineralogy 2 (2012) 241-252.

[7] Boomeri M., Biabangard H., Nakashima K., Esform M., ″Occurrence and chemistry of supergene sulfide and oxide minerals in Mahour polymetal ore deposit west of Nehbandan, (in Persian)″, Petrology 14(2013) 17-30.

[8] Gourabjeri Puor A., Mobasheri M., ″Compiling Data from Geological, Mineralogical and Geophysical (IP/RS) Studies on Mahour Deposit, Northwest of Deh-salm, Lut Block, (in Persian)″, Journal of Economic geology 7 (2016) 307-325.

[9] Miri Beydokhti R., Karimpour M. H., Mazaheri S. A., Santos J. F., Klotzli U., ″U-Pb zircon geochronology, Sr – Nd geochemistry, petrogenesis and tectonic setting of Mahoor granitoid rocks (Lut Block, Eastern Iran)″, Journal of Asian Earth Sciences 111(2015) 192-205.

[10] Younesi S., Hosseinzadeh M.R., Moayyed M., Maghsoudi A., ″Investigation of geology, petrology and petrogenesis of igneous rocks from the Mahour Mining exploration area, west Dehsalm: Implication for Lut tectonomagmatic setting, (in Persian)″, Scientific Quarterly Journal of Geosciences, 27(2016) 179-198.

[11] Younesi S., Hosseinzadeh M.R., Moayyed M., ″Mineralogy of Mahour Zn-Cu-(pb-Bi-Ag) deposit, west of Dehsalm: implications for genesis and mineralization type, (in Persian)″ ,Scientific Quarterly Journal of Geosciences, 27(2017) 295-308.

[12] Whitney D. L., Evans B. W., "Abbreviations for names of rock-forming minerals", American Mineralogist 95 (2010) 277-279.

[13] Pars kani Co. ″Detailed report of Mahoor prospecting area(Nehbandan city, South Khorasan province), (in persion)″, (2012).

[14] Sasaki K., Konno H., ″Morphology of jarosite-group compounds precipitated from biologically and chemically oxidized Fe ions″, Cantribution mineral petrology 38 (2000) 45–66.

[15] Brown P. E., Lamb W. M., ″P-V-T properties of fluids in the system H2O-CO2-NaCl: New graphical presentations and implications for fluid inclusion studies″, Geochim. Acta 53 (1989) 1209-1221.

[16] Sheppherd T. J., Rankin A. H., Alderton D. H. M., ″A Practical Guide to Fluid Inclusion Studies″, Blackie and Son (1985) 239 p.

[17] Hall A. J., Boyee A. J., Fallick A. E., Hamilton P. J., ″Isotopic evidence of the depositional environment of Late Proterozoic stratiform barite mineralisarion, Aberfeldy, Scotland″, Chem. Geol. Isotope Geosci. Sect. 87 (1991) 99-114.

[18] Seward T. M., ″The hydrothermal geochemistry of gold, in: Foster R. P., (ed.), gold metallogeny and exploration″, Blakie and Sons Ltd. (1991) 432 p.

[19] Seward T. M., ″Thio complexes of gold and the transport of gold in hydrothermal solutions″, Geochim, cosmochim, Acta 37 (1973) 379-399.

[20] Wilkinson J. J., ″Fluid inclusions in hydrothermal ore deposits″, Lithos 55 (2001) 229-272.

[21] Ohmoto H., Rye R. O., ″Isotopes of sulfur and carbon, In: Barnes, H. L. (Ed.) Geochemistry of hydrothermal ore deposits″, John Wiley and Sons, New York (1979) 509–567.

[22] Li Y. B., Liu J. M., ″Calculation of sulfur isotope fractionation in sulfides″, Geochimica et Cosmochimica Acta 70 (2006) 1789-1795.

[23] Rye RO, Bethke P.M, Wasserman M.D., ″The stable isotope geochemistry of acid sulfate″, Economic Geology 87(1992) 227–262.

[24] Rye R.O., ″A review of stable isotope geochemistry of sulfate minerals in selected igneous environments and related hydrothermal systems″, Chem Geol 215(2005) 5–36.

[25] Seal II Robert, R., ″Sulfur Isotope Geochemistry of Sulfide Minerals″, Reviews in Mineralogy and Geochemistry 61(2006) 633-677.

[26] Faure G., ″Principles of Isotope Geology″, second ed. John Wiley and Sons Inc., New York, (1986) 598p.

[27] Brownlow A. H., ″Geochemistry″, Prentice Hall, Englewood Cliffs, New Jersey(1979).

[28] Parsapoor A., Khalili M., Maghami M., Bagheri H. ″The investigation on physico-chemical conditions of sulfides and sulfates based on petrographic and sulfur - oxygen stable isotope studies from the Darreh-Zar porphyry copper deposit, Kerman, (in Persian)″, Iranian Journal of Economic geology 6 (2014) 177-197.

[29] Taghipour N., Dorani M., ″Geochemistry of Sulfur and Oxygen stable isotopes in Sulfide and Sulfate minerals at Parkam porphyry copper deposit, Shahr-e-Babak, Kerman province, (in Persian)″, Jouranl of Advanced Applied Geology, 8 (2013) 61-70.

[30] Maanijou M., Mostaghimi M., Abdollahi Riseh M., Sepahi A.A., ″Systematic sulfur stable isotope and fluid inclusion studies on veinlet groups in the Sarcheshmeh porphyry copper deposit: based on new data, (in Persian)″, Iranian Journal of Economic geology 4(2012) 217- 239.

[31] Wang Y.H., Zhang F.F., Liu J.J., Yang Que, C., ″Genesis of the Fuxing porphyry Cu deposit in Eastern Tianshan, China: Evidence from fluid inclusions and C–H–O–S–Pb isotope systematics″, Ore Geology Reviews 79(2016) 46-61.

[32] Peng B., Sun F., Li B., ″Geochronology and geochemistry of Tianhexing porphyry Cu-Mo deposit, northeast China″, Ore Geology Reviews 197(2018) 130-142.

[33] Richards J.P., ″Tectono-magmatic precursors for porphyry Cu–(Mo–Au) deposit formation″, Economic Geology 98 (2003) 1515–1533.

[34] Cooke D.R., Hollings P., Walshe J.L., ″Giant porphyry deposits: characteristics, distribution, and tectonic controls″, Economic Geology 100 (2005) 801–818.

[35] Hou Z., Cook N.J., ″Metallogenesis of the Tibetan collisional orogen: A review and introduction to the special issue″, Ore Geology Reviews 36 (2009) 2–24.

[36] Aghazadeh, M., Hou, Z., Badrzadeh, Z., Zhou, L., "Temporal–spatial distribution and tectonic setting of porphyry copper deposits in Iran: Constraints from zircon U–Pb and molybdenite Re–Os geochronology", Ore Geology Reviews (2015). doi:10.1016/j.oregeorev.2015.03.003.

[37] McCall, G.J.H., "The geotectonic history of the Makran and adjacent areas of southern Iran". J. SE Asian Earth Sci. 15 (1997), 517–531.

[38] Arjmandzadeh, R., Karimpour, M.H., Mazaheri, S.A., Santos, J.F., Medina, J.M., Homam, S.M., "Sr/Nd isotope geochemistry and petrogenesis of the Chah-Shaljami granitoids (Lut Block, Eastern Iran)". Journal of Asian Earth Sciences 41 (2011), pp. 283-296.

[39] Zarrinkoub, M.H., Pang, K.N., Chung, S.L., Khatib, M.M., Mohammadi, S.S., Chiu, H.Y., Lee, H.Y., "Zircon U/Pb age and geochemical constraints on the origin of the Birjand ophiolite, Sistan suture zone, eastern Iran". Lithos 154 (2012), 392-405.

[40] Richards, J.P., Spell, T., Rameh, E., Razique, A., Fletcher, T. "High Sr/Y magmas reflect arc maturity, high magmatic water content, and porphyry Cu ± Mo ± Au potential: examples from the Tethyan arcs of Central and Eastern Iran and Western Pakistan". Economic Geology 107 (2012), pp. 295–332.

[41] Pang, K.N., Chung, S.L., Zarrinkoub, M.H., Khatib, M.M., Mohammadi, S.S., Chiu, H.Y., Chu, C.H., Lee, H.Y., Lo, C.H., "Eocene–Oligocene post-collisional magmatism in the Lut–Sistan region, eastern Iran: magma genesis and tectonic implications". Lithos 180–181 (2013), 234–251.

[42] Malekzadeh Shafaroudi, A., Karimpour, M.H., Stern, C.R., "The Khopik porphyry copper-gold prospect, Lut Block, Eastern Iran: geology, alteration, mineralization, fluid inclusion, and oxygen isotope studies". Ore geology Reviews 65 (2015), Part 2, Pages 522–544.

[43] Siahcheshm, K., Calagari, A., Abedini, A., "Hydrothermal evolution in the Maher-Abad porphyry Cu-Au deposit, SW Birjand, Eastern Iran: Evidence from fluid inclusions". Ore Geology Reviews 58 (2014), pp 1-13.

[44] Arjmandzadeh, R., Santos, J.F., "Sr-Nd isotope geochemistry and tectonomagmatic setting of the Dehsalm Cu-Mo porphyry mineralizing intrusives from Lut Block, eastern Iran". International Journal of Earth Sciences 103 (2014), Issue 1, pp 123-140.

[45] Yang Z., Hou Z., White N.C., Chang Z., Li Z., Song Y., ″Geology of the post-collisional porphyry copper–molybdenum deposit at Qulong, Tibet″, Ore Geology Reviews 36 (2009) 133–159.

[46] Lowell J. D., Guilbert J. M., ″Lateral and vertical alteration– mineralization zoning In porphyry ore deposits″, Economic Geology 65 (1970) 373–408.

[47] Miri Beydokhti, R., ″Mineralization, alteration, petrology and age dating of intrusive rocks, southwest-west of Dehsalm, (in Persian)″, Ph.D thesis, Ferdowsi University of Mashhad (2016) 247 p.

[48] Sillitoe R. H, ″Porphyry Copper Systems″, Economic Geology 105 (2010) 3–41.

[49] Gustafson L.B., ″Some major factors of porphyry copper genesis″, Economic Geology 73 (1978) 600–607.

[50] Frotteir G.L., Burov E., ″The development and fracturing of plutonic apexes: implications for porphyry ore deposits″, Earth and Planetary Science Letters 214 (2003) 341-356.