Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Mineral chemistry, thermobarometry, and petrogenesis of igneous rocks from the Negisan area, east of Rudbar, Kerman province, Iran

Document Type : Original Research Paper

Authors
Mehrnaz Zaifi 1
Gholamreza Ghadami 1
Mohammad Poosti 1
Mohammad Fadaeian 2
1 Department of Geology, Faculty of Sciences, University of Hormozgan, Bandar Abbas, Hormozgan, Iran
2 Department of Geology, Faculty of Sciences, Payame Noor University, Tehran, Iran
10.22071/gsj.2026.561524.2236
Abstract
This study investigates the mineral chemistry, thermobarometric conditions, and petrogenetic evolution of Quaternary basaltic and olivine–basaltic lava flows exposed in the Negisan area, located in the southeastern segment of the Urumieh–Dokhtar Magmatic Arc (UDMA) and within the Dehaj–Sarduiyeh Magmatic Belt (DSMB). These volcanic units consist predominantly of porphyritic to glomeroporphyritic basalts characterized by phenocrysts of plagioclase (bytownite–labradorite), clinopyroxene (diopside–augite), and olivine (chrysolite), set within a microcrystalline to hyalomicrolitic groundmass. Comprehensive petrographic analysis reveals the pervasive presence of disequilibrium textures, including sieve-textured plagioclase and embayed olivine, indicative of dynamic open-system magmatic evolution. Quantitative major-element data obtained by electron probe microanalysis (EPMA) offer robust constraints on the physicochemical conditions of mineral crystallization. Clinopyroxene compositions correspond to an alkaline magma affinity and plot within the within-plate basalt tectonomagmatic field. Single-mineral thermobarometric calculations using clinopyroxene chemistry yield crystallization temperatures of 1160–1200 °C and pressures of 2–5 kbar, corresponding to mid- to upper-crustal magma storage depths (~7–18 km), under oxidizing and water-rich magmatic conditions. Systematic compositional contrasts between the olivine basalts (less evolved) and basalts (more evolved) demonstrate that fractional crystallization was the dominant differentiation mechanism. Nonetheless, petrographic evidence for magma mixing indicates that open-system recharge and interaction were also essential in magma evolution. These findings collectively support a model in which Negisan mafic volcanism represents late-stage, post-collisional magmatic activity associated with extensional tectonics following the final closure of the Neo-Tethys Ocean beneath the Central Iran microplate. The integration of petrography, mineral chemistry, and thermobarometry provides new insights into the magmatic plumbing system and geodynamic evolution of the southeastern UDMA.
Keywords
Alkaline basalt
Mineral chemistry
Thermobarometry
Negisan
Dehaj-Sarduiyeh
Kerman
Subjects
Agard, P., Omrani, J., Jolivet, L., and Mouthereau, F., 2005. 'Convergence history across Zagros (Iran): constraints from collisional and earlier deformation', International Journal of Earth Sciences, 94(3), pp. 401-419. doi: 10.1007/s00531-005-0481-4.
Agard, P., Omrani, J., Jolivet, L., Whitechurch, H., Vrielynck, B., Spakman, W., Monié, P., Meyer, B., and Wortel, R., 2011. Zagros orogeny: a subduction-dominated process. Geological Magazine 148(5-6), 692-725. https://doi.org/10.1017/S001675681100046X
Ahmadzadeh, G., Jahangiri, A., Lentz, D., and Mojtahedi, M., 2010. `Petrogenesis of Plio-Quaternary post-collisional ultrapotassic volcanism in NW of Marand, NW Iran`, Journal of Asian Earth Sciences, 39(1-2), pp.37-50.
Alavi, M., 1994. 'Tectonics of the Zagros orogenic belt of Iran: new data and interpretations', Tectonophysics, 229(3-4), pp. 211-238. doi: 10.1016/0040-1951(94)90030-2.
Allen, M.B., Kheirkhah, M., Emami, M.H., and Jones, S.J., 2013. 'Generation of Arc and Within-plate Chemical Signatures in Collision Zone Magmatism: Quaternary Lavas from Kurdistan Province, Iran', Journal of Petrology, 54(5), pp. 887-911. doi: 10.1093/petrology/egt002.
Aoki, K. I., and Kushiro, I., 1968. `Some Clinopyroxenes from Ultramafic Inclusions in Dreiser Weiher, Eifel` Contributions to Mineralogy and Petrology, 18, 326-337. https://doi.org/10.1007/bf00399694.
Bahraman, S., 2017. `Geochemistry and petrogenesis of Quaternary volcanic rocks, north of Zehkalut, east of Kerman province` M.Sc. thesis, Faculty of Basic Sciences, University of Hormozgan, 126 p, (in Persian).
Beccaluva, L., and Serri, G., 1988. 'Boninitic and low-Ti subduction-related lavas from the northern Apennine ophiolites', Canadian Journal of Earth Sciences, 25(7), pp. 1055-1071. doi: 10.1139/e88-103.
Berberian, M., and King, G.C.P., 1981. 'Towards a paleogeography and tectonic evolution of Iran', Canadian Journal of Earth Sciences, 18(2), pp. 210-265. doi: 10.1139/e81-019.
Berger, J., Féménias, O., Mercier, J.C.C., and Demaiffe, D., 2005. 'A new geochemical tool to distinguish between igneous and metamorphic pyroxenes', Lithos, 82(1-4), pp. 21-34. doi: 10.1016/j.lithos.2004.12.001.
Chiu, H.Y., Chung, S.L., Zarrinkoub, M.H., Mohammadi, S.S., and Khatib, M.M., 2013. 'Zircon U–Pb age constraints from the Urumieh–Dokhtar magmatic arc, Iran, on the magmatic response to Neotethyan subduction and Zagros collision', Lithos, 162, pp. 72-87. doi: 10.1016/j.lithos.2012.12.012.
Deer, W.A., Howie, R.A., and Zussman, J., 1992. An Introduction to the Rock-Forming Minerals. 2nd edn. London: Longman Scientific & Technical.
Dimitrijević, M.D., and Dimitrijević, M.N., 1973. `Olistostrome mélange in the Yugoslavian Dinarides and late Mesozoic plate tectonics`, The Journal of geology, 81(3), pp.328-340.
Eftekharnejad, J., 1987. Geological map of Nagisan, Scale 1:100,000. Tehran: Geological Survey and Mineral Exploration of Iran.
Fedele, L., Rahimzadeh, B., Salari, G., Agostini, S., and Masoudi, F., 2022. `A showcase of igneous processes in the Urumieh–Dokhtar Magmatic Arc: The Miocene-Quaternary collisional magmatism of the Bijar-Qorveh area, northwest Iran`, Journal of Petrology, 63(7), egac047. https://doi.org/10.1093/petrology/egac047.
France, L., Koepke, J., Ildefonse, B., Cichy, S.B., and Deschamps, F., 2010. 'A new appraisal of the Al-in-clinopyroxene barometer: evidence from the Skaergaard intrusion', Contributions to Mineralogy and Petrology, 160(5), pp. 755-767. doi: 10.1007/s00410-010-0503-x.
Ghasemi, A., and Talbot, C.J., 2006. 'A new tectonic scenario for the Sanandaj–Sirjan Zone (Iran)', Journal of Asian Earth Sciences, 26(6), pp. 683-693. doi: 10.1016/j.jseaes.2005.01.003.
Ghorbani, M. R., Akbari, M., Graham, I. T., Benoit, M., and Sepidbar, F., 2025. `What do arc magmatism trace-element patterns and Sr–Nd–Pb isotopic data reflect? Insights from the Urumieh–Dokhtar magmatic arc of Iran`, Solid Earth, 16, 663–680. https://doi.org/10.5194/se-16-663-2025.
Ghorbani, M., 2013. The Economic Geology of Iran: Mineral Deposits and Natural Resources. Dordrecht: Springer Science & Business Media.
Hassanzadeh, J., 1993. `Metallogenic and tectonomagmatic events in the SE sector of the Cenozoic active continental margin of central Iran (Shahr e Babak area, Kerman Province)`, University of California, Los Angeles.
Helz, R.T., 1973. 'Phase relations of basalts in their melting range at PH2O= 5 kb as a function of oxygen fugacity: part I. Mafic phases', Journal of Petrology, 14(2), pp. 249-302. doi: 10.1093/petrology/14.2.249.
Jahangiri, A., 2007. 'Post-collisional Miocene adakitic volcanism in NW Iran: Geochemical and geodynamic implications', Journal of Asian Earth Sciences, 30(3-4), pp. 433-447. doi: 10.1016/j.jseaes.2006.11.003.
Jankovics, M. É., Dobosi, G., Embey-Isztin, A., Kiss, B., Sági, T., Harangi, S. Ntaflos, T., 2013 `Origin and Ascent History of Unusually Crystal-Rich Alkaline Basaltic Magmas from the Western Pannonian Basin` Bulletin of Volcanology, 75, Article No. 749. https://doi.org/10.1007/s00445-013-0749-7.
Khodami, M., Noghreyan, M., and Davoudian, A., 2009 `PlioceneQuaternary Adakite volcanism in the Isfahan area, Central Iranian magmatic belt` Neues Jahrbuch für Mineralogie-Abhandlungen, pp. 235-248.
Le Bas, M.J., 1962. 'The role of aluminum in igneous clinopyroxenes with relation to their parentage', American Journal of Science, 260(4), pp. 267-288. doi: 10.2475/ajs.260.4.267.
Leterrier, J., Maury, R.C., Thonon, P., Girard, D., and Marchal, M., 1982. 'Clinopyroxene composition as a method of identification of the magmatic affinities of Paleo-volcanic series', Earth and Planetary Science Letters, 59(1), pp. 139-154. doi: 10.1016/0012-821X(82)90122-4.
Mansouri, A., 2018` Geochemistry and petrogenesis of dacite-andesite domes, north of Zehalut, east of Kerman province`, M.Sc. thesis, Faculty of Basic Sciences, University of Hormozgan, 191 p, (in Persian).
Middlemost, E.A.K., 1986. Magmas and Magmatic Rocks: An Introduction to Igneous Petrology. London: Longman Group.
Mohajjel, M., Fergusson, C.L., and Sahandi, M.R., 2003. 'Cretaceous–Tertiary convergence and continental collision, Sanandaj–Sirjan Zone, western Iran', Journal of Asian Earth Sciences, 21(4), pp. 397-412. doi: 10.1016/S1367-9120(02)00035-4.
Mohammadi, S., 2007 `Petrology and geochemistry of rocks from the Negisan area`, Ph.D. dissertation, Faculty of Earth Sciences, Shahid Beheshti University, 264 p, (in Persian).
Morimoto, N., and Kitamura, M., 1983. 'The Q-J diagram for classification of pyroxenes', Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 78, pp. 193-199.
Morimoto, N., Fabries, J., Ferguson, A.K., Ginzburg, I.V., Ross, M., Seifert, F.A., Zussman, J., Aoki, K., Gottard, G., 1988. 'Nomenclature of pyroxenes', American Mineralogist, 73(9-10), pp. 1123-1133.
Mouthereau, F., Lacombe, O., and Vergés, J., 2012. 'Building the Zagros collisional orogen: timing, strain distribution and the dynamics of Arabia/Eurasia plate convergence', Tectonophysics, 532, pp. 27-60. doi: 10.1016/j.tecto.2012.01.027.
Nelson, S.T., and Montana, A., 1992. `Sieve-textured plagioclase in volcanic rocks produced by rapid decompression`, American mineralogist, 77(11-12), pp.1242-1249.
Nezafati, N., 2006. `Au-Sn-W-Cu Mineralization in the Astaneh-Sarband Area, West Central Iran including a comparison of the ores with ancient bronze artifacts from Western Asia`, Doctoral dissertation, University of Freiberg.
Omrani, J., Agard, P., Whitechurch, H., Benoit, M., Prouteau, G., and Jolivet, L., 2008. 'Arc magmatism and subduction history beneath the Zagros Mountains, Iran: a new report of adakites and geodynamic consequences', Lithos, 106(3-4), pp. 380-398. doi: 10.1016/j.lithos.2008.09.007.
Reubi, O., and Blundy, J., 2009. `A dearth of intermediate melts at subduction zone volcanoes and the petrogenesis of arc andesites`, Nature, 461(7268), pp.1269-1273.
Richards, J.P., 2015. 'Tectonic, magmatic, and metallogenic evolution of the Tethyan orogen: From subduction to collision', Ore Geology Reviews, 70, pp. 323-345. doi: 10.1016/j.oregeorev.2014.11.009.
Sarjoughian, F., and Kananian, A., `2017. `Zircon U–Pb geochronology and emplacement history of intrusive rocks in the Ardestan section, central Iran`, Geologica Acta, 15(1), 25–36. https://www.redalyc.org/journal/505/50549984003/html/ .
Schweitzer, E.L., Papike, J.J., and Bence, A.E., 1979. 'Statistical analysis of clinopyroxenes from deep-sea basalts', American Mineralogist, 64(5-6), pp. 501-513.
Shafiei, B., Haschke, M., and Shahabpour, J., 2009. 'Recycling of orogenic arc crust triggers porphyry Cu mineralization in Kerman Cenozoic arc rocks, SE Iran', Mineralium Deposita, 44(3), pp. 265-283. doi: 10.1007/s00126-008-0216-1.
Shahabpour, J., 2005. 'Tectonic evolution of the porphyry copper deposits in the Kerman region, SE Iran', Journal of Asian Earth Sciences, 25(1), pp. 1-17. doi: 10.1016/j.jseaes.2004.01.003.
Shahabpour, J., 2007. 'Island-arc affinity of the central Iranian volcanic belt', Journal of Asian Earth Sciences, 30(5-6), pp. 652-665. doi: 10.1016/j.jseaes.2007.02.001.
Soesoo, A., 1997. 'A new single-clinopyroxene thermometer and its application to the Otepää intrusion, Estonia', GFF, 119(1), pp. 51-56. doi: 10.1080/11035899709546252.
Stöcklin, J., 1968. `Structural history and tectonics of Iran: a review`, AAPG bulletin, 52(7), pp.1229-1258.
Torabi, G., 2009. Subduction-related Eocene shoshonites from the Cenozoic Urumieh–Dokhtar magmatic arc (Qaleh-Khargooshi area, west of Yazd province, Iran). Turkish Journal of Earth Sciences, 18(4), 583–613. https://doi.org/10.3906/yer-0711-2.
Verdel, C., Wernicke, B.P., Hassanzadeh, J., and Guest, B., 2011. 'A Paleogene extensional arc flare-up in Iran', Tectonics, 30(3), TC3008. doi: 10.1029/2010TC002809.
Scientific Quarterly Journal of Geosciences
Volume 36, Issue 2 - Serial Number 140
Summer 2026, Vol. 36, Issue 2, Serial No. 140
Spring 2026
Pages 85-102