Application of clinopyroxene as a petrogenic mineral in determining the nature of Ordovician intrusive rocks in Ziarat (Southern Gorgan, Golestan Province)

Document Type : Research Article

Authors

• Qassem Azizzadeh
• Seyed Jamal Sheikhzakariaee
• Mostafa Raghimi
• Aziz Rahimi Chakdel

Department of Earth Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran

10.22067/econg.v13i3.81312

Abstract

Introduction
The study area is located in the Eastern Alborz zone (Gansser, 1951) which is a part of the northern margin of Gondwana during the Paleozoic (Stöcklin, 1974; Salehi Rad, 1979; Berberian and King, 1981; Şengor, 1990; Alavi, 1991, 1996; Stampfli and Borel, 2002; Allen et al., 2003; Horton et al., 2008; Sinha, 2012, 2013). According to studies conducted by Gansser (1951) and Hubber (1957), the gabbro masses of South Gorgan (Nahar Khuran Valley) belong to the ophiolite collection. Meanwhile, 6km South-East of Galougah city, Gorgan schists have been covered by underlying Jurassic sandstones with s steep discontinuity. The parts resulting from the erosion of Gorgan schists were observed in the sequence conglomerate of the underlying Jurassic. At the beginning of the Ziarat Valley, about 800 meters above the Nahar Khuran, two small tectonic masses (the thickness of about 11 meters) are placed on the layers. These masses are mostly metamorphic. The metamorphic rocks (Gorgan schists), as one of the important geological units in Iran, are mainly formed from low-metamorphic rocks such as slate, phyllite, chlorite schist, greenschist and micaschist along with volcanic rocks and gabbrodiorite masses infiltrating them.
 
Materials and Methods
To prepare a geological map of the study area, field sampling and fieldwork were first done from the various units in the region. Over 100 samples were collected from the area. Approximately 70 thin cross-sectional samples of the tectonic rocks of the area were selected from them and investigated using a polarizing microscope. In this paper, 11 points of clinopyroxene were selected for microprobe analysis. The point analysis done on these minerals was conducted using the EPMA method using a microprobe analysis set in the Center of Mineral Processing of Iran (Karaj). The structural formula is calculated using the Excel (Spreadsheet) and dividing them was done by the MinPet 2.02 software package. Given that microprobe analysis is unable to distinguish Fe2⁺ and Fe3⁺ and given that it reports total iron as FeO*, it is necessary to separate these two from each other in order to calculate the minerals’ structural formula.
 
Results
Petrographic studies identified rocks including gabbro, olivine gabbro, monzonite, gabbro to monzogabbro altered, metagabbro, and catalactic porphyry diorite. Mineralogically, these rocks consist of phenocrysts of plagioclase with labradorite composition, clinopyroxene and olivine with accessory minerals of apatite, sphene, biotite, and metal minerals. Secondary minerals are chlorite, sericite, clay mineral and epidote. The dominant textures in these rocks are granular and ophitic. The results of electron microprobe analysis of these clinopyroxenes show that they have augite compositions. In addition, gabbros also mostly show alkaline composition. 
 
Discussion
To precisely investigate the rocks in the research area, the results of the chemical analyses of minerals were used in determining their petrogenesis. Felsic minerals mainly include altered plagioclase, the main combination of which is labradorite and which is converted to the secondary albite due to hydrothermal alteration processes. The combination of clinopyroxenes available in the volcanic rocks is in Quad range and has a composition of augite. The temperature calculated for the clinopyroxenes in gabbros is 1277.7 to 1353.1°C and the pressure is more than 10 Kbars.  (On the baseline of 3.65kbar per 1km in depth), the formation of clinopyroxenes in the parent magma was over 37km. The primary water content of the gabbro magmas is estimated to have been between 0.5 and 5 wt.%. Distribution of aluminum in tetra and octa positions of clinopyroxenes depends on pressure and the amount of water available in the crystallization environment. Accordingly, the amount of Al^IV decreases as the amount of water increases. Tectonomagmatic diagrams suggest that the host rocks are alkaline and are related to volcanic arc setting.
 
References
Alavi, M., 1991. Sedimentary and structural characteristics of the Paleo–Tethys remnants in northeastern Iran. Geological Society of America Bulletin, 103(8): 983–992.  https://doi.org/10.1130/0016-7606(1991)103<0983:SASCOT>2.3.CO;2
Alavi, M., 1996. Tectonostratigraphic synthesis and structural style of the Alborz mountain system in northern Iran. Journal of Geodynamics, 21(1): 1–33. https://doi.org/10.1016/0264-3707(95)00009-7
Allen, M.B., Ghassemi, M.R., Shahrabi, M. and Qorashi, M., 2003. Accommodation of late Cenozoic oblique shortening in the Alborz range, northern Iran. Journal of Structural Geology, 25(5): 659–672. https://doi.org/10.1016/S0191-8141(02)00064-0
Berberian, M. and King, G.C.P., 1981. Toward apaleogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences, 18(2): 210–265. https://doi.org/10.1139/e81-019
Gansser, A., 1951. Geological reconnaissance in the Gorgan and surrounding areas. Geological Survey of Iran, Tehran, report 18, 37 pp.
Hubber, H., 1957. Geological reporte on south Gorgan mountain front between Nika and Shah-Pasand. National Iran Oil Company, Tehran, report 164, 39 pp.
Salehi Rad, M.R., 1979. Etude géologique de la region de Gorgan (Alborz oriental, Iran). Ph.D. Thesis, University of Paris, Paris, France, 162 pp.
Şengor, A.M.C., 1990. A new model for the late Palaeozoic–Mesozoic tectonic evolution of Iran and implications for Oman. Geological Society of London, 49‌(1): 797–831. http://dx.doi.org/10.1144/gsl.sp.1992.049.01.49
Sinha A.K., 2012. Petrological characterization of Proterozoic mafic dykes from the Singhbhum craton, eastern India, 34^th International Geological Congress, University of Queensland, Brisbane, Australia.
Sinha, A.K., 2013. Geochemistry of distinct mafic dykes from the Damodar valley Gondwana basins and Chhotanagpur gneissic terrain, eastern India: implications for their petrogenesis and tectonic setting. 125^th anniversary of The Geological Society of America, Cornell University, New York, USA.
Stampfli, G.M. and Borel, G.D., 2002. A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrones. Earth and Planetary science letters 196 (1–2): 17–33. https://doi.org/10.1016/S0012-821X(01)00588-X
Stöcklin, J., 1974. Possible ancient continental margins in Iran. In: C.A. Burk and C.L. Drake (Editors), The geology of continental margins. Springer, New York, pp. 873–887. https://doi.org/10.1007/978-3-662-01141-6_64

Keywords

• Clinopyroxene
• Geothermobarometry
• Alkaline series
• Ordovician
• Alborz structural zone
• Gorgan

20.1001.1.20087306.1400.13.3.4.2

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References

Alavi, M., 1991. Sedimentary and structural characteristics of the Paleo–Tethys remnants in northeastern Iran. Geological Society of America Bulletin, 103(8): 983–992.  https://doi.org/10.1130/0016-7606(1991)103<0983:SASCOT>2.3.CO;2

Alavi, M., 1996. Tectonostratigraphic synthesis and structural style of the Alborz mountain system in northern Iran. Journal of Geodynamics, 21(1): 1–33. https://doi.org/10.1016/0264-3707(95)00009-7

Allen, M.B., Ghassemi, M.R., Shahrabi, M. and Qorashi, M., 2003. Accommodation of late Cenozoic oblique shortening in the Alborz range, northern Iran. Journal of Structural Geology, 25(5): 659–672. https://doi.org/10.1016/S0191-8141(02)00064-0

Azizzadeh, Q., Raghimi, M., Sheikhzakariaee, S. and Rahimi Chakdel, A., 2018. Geochemical characteristics of Gabbroic rocks in Zyarat in North East of Iran. Bulletin of the Mineral Research and Exploration, 157‌‌(157): 153–164. https://doi.org/10.19111/bulletinofmre.413716

Beccaluva, L., Macciotta, G., Piccardo, GB. and Zeda, O., 1989. Clinopyroxene composition of ophiolite basalts as petrogenetic indicator. Chemical Geology, 77‌(3–4): 165–182. https://doi.org/10.1016/0009-2541(89)90073-9

Berberian, M. and King, G.C.P., 1981. Toward apaleogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences, 18(2): 210–265. https://doi.org/10.1139/e81-019

Berger, J., Femenias, O., Mercier, J.C.C. and Demaiffe, D., 2005. Ocean-floor hydrothermal metamorphism in the Limousin ophiolites (western French Massif Central): evidence of a rare preserved Variscan oceanic marker. Journal of Metamorphic Geology, 23(9): 795–812. https://doi.org/10.1111/j.1525-1314.2005.00610.x

Brunet, M.F., Ershov, A.V., Korotaev, M.V. and Nikishin, A.M., 2003. The South Caspian basin: a review of its evolution from subsidence modelling. Sedimentary Geology, 156(1–4): 119–148. https://doi.org/10.1016/S0037-0738(02)00285-3

Darvishzadeh, A., 1991. Geology of Iran. Neda Publication, Tehran, 901 pp.

Dioh, E., Béziat, D., Grégoire, M. and Debat, P., 2009. Origin of rare earth element variations in clinopyroxene from plutonic and associated volcanic rocks from the Foulde basin, Northern Kedougou inlier, Senegal, West Africa. European Journal of Mineralogy, 21(5): 1029–1043. https://doi.org/10.1127/0935-1221/2009/0021-1963

Downes, H. and Leyreloup, A., 1986. Granulitic Xenoliths from the french massif central, Petrology, Sr and Nd isotope systematics and model age estimatics. Geological Society London, 24(1): 319–330. https://doi.org/10.1093/petroj/40.10.1465

Droop, G.‌T.‌R., 1987. A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria. Mineralogical Magazine, 51(361): 431–435. https://doi.org/10.1180/minmag.1987.051.361.10

Eickmann, B., Bach, W., Rosner, M. and Peckmann, J., 2009. Geochemical constraints on the modes of carbonate precipitation in peridotites from the Logatchev Hydrothermal Vent Field and Gakkel Ridge. Chemical Geology, 268(1–2): 97–106. https://doi.org/10.1016/j.chemgeo.2009.08.002

Foley, S.‌F. and Venturelli, G., 1989. Boninites and Related Rocks. Springer, New York, 496 pp.

Fotovat Roudsari, H., 2006. Structural analysis of shear zones in Gorgan Transformation Collection, M.Sc. Thesis, Tarbiat Modares University, Tehran, Iran, 77 pp.

Gansser, A., 1951. Geological reconnaissance in the Gorgan and surrounding areas. Geological Survey of Iran, Tehran, report 18, 37 pp.

Ghasemi, H., Kazemi, Z. and Salehian, Sh., 2015. Comparision of the Mafic Igneous Rocks from the Ghelli Formation (Upper Ordovician) and the Gorgan Schists in the Eastern Alborz Zone. Geosciences, 24(96): 263–301.  https://doi.org/10.22071/GSJ.2015.41771

Ghavidel-Syooki, M., 2009. Palynostratigraphy and paleogeography of Ordovician strata (Abastu and Abarsaj formations) from the southeastern Caspian Sea, northeastern Iran. Joint meeting of spores-pollen and acritarch subcommissions, University of the Algarve, Faro, Portugal.

Ghorbani, H., Moazen, M. and Saki, A., 2019. Comparison of the Thermometery-Barometery methods by using Thermocalc and Theriak-domino to study Calc- silicate Hornfelses in Cheshin, Hamedan. Journal of Economic Geology, 11(2): 195–209. (in Persian with English abstract) https://doi.org/10.22067/ECONG.V11I2.66002

Green, D.H. and Ringwood, A.E., 1967. The genesis of basaltic magmas. Contributions to Mineralogy and Petrology, 15(2): 103–109. https://doi.org/10.1007/BF00372052

Helz, R.T., 1976. Phase relations of basalts in their melting range at PH2O = 5 kb. Part Π Melt compositions, Journal of Petrology, 17(2): 139–193.  https://doi.org/10.1093/petrology/14.2.249

Horton, B.K., Hassanzadeh, J., Stockli, D.F., Axen, G.J., Gillis, R.J., Guest, B., Amini, A.H., Fakhari, M., Zamanzadeh, S.M. and Grove, M., 2008. Detrital zircon provenance of Neoproterozoic to Cenozoic deposits in Iran: Implications for chronostratigraphy and collisional tectonics. Tectonophysics, 451(1–4): 97–122. https://doi.org/10.1016/j.tecto.2007.11.063

Hubber, H., 1957. Geological reporte on south Gorgan mountain front between Nika and Shah-Pasand. National Iran Oil Company, Tehran, report 164, 39 pp.

Jamshidi, Kh., Afsharian, A., Sahbaie, M., and Dehhaghi, F., 1991. 1:250000 geological map of Gorgan. Geological Survey and Mineral Exploration of Iran Press.

Jenny, J.G., 1977. Precambrien et Paleozoique inferieur de l’Elbourz oriental entre Aliabad et Shahrud, Iran du nord–est. Eclogae Geologicae Helvetiae 70(1): 761–770. https://doi.org/10.19111/bulletinofmre.413716

Kretz, R., 1983. Symbols of rock-forming minerals. American Mineralogist, 68(2): 277–279. https://doi.org/10.1130/B26587

Le Bas, M.‌J., 1962. The role of aluminum in igneous. Clinopyroxenes with relation to their parentage. American Journal of Science, 260(4): 267–288. https://doi.org/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): 139–154. https://doi.org/10.1016/0012-821X(82)90122-4

Lindsley, D.H., 1983. Pyroxene thermometry. American Mineralogist, 68(5–6): 477–493. https://doi.org/10.29252/ijcm.27.3.707

Liu, T.‌C., Chen, B.‌R. and Chen, C.‌H., 2000. Melting experiment of a Wannienta Basalt in the Kuanyinshan area, northern Taiwan. Journal of Asian Earth Sciences, 18(5): 519–531. https://doi.org/10.1016/S1367-9120(00)00002-X

Morimoto, N., Fabrise, J., Ferguson, A., Ginzburg, I.‌V., Ross, M., Seifert, F.‌A., Zussman, J., Aoki, K. and Gottardi, G., 1988- Nomenclature of pyroxene, Mineralogical Magazine, 52(367): 535–‌55. https://doi.org/10.22067/econg.v8i2.46817

Nakamura, D., 2009. A new formulation of garnet- clinopyroxene geothermometer based on accumulation and statistical analysis of a large experimental data set. Journal of Metamorphic Geology, 27(7): 495–508. https://doi.org/10.1111/j.1525-1314.2009.00828.x

Nimis, P.A., 1995. A clinopyroxene geobarometer for basaltic systems based on crystal-structure modeling. Contributions to Mineralogy and Petrology, 121(2): 115–125. https://doi.org/10.1007/s004100050093

Nimis, P. and Taylor, W.R., 2000. Single clinopyroxene thermobarometry for garnet peridotite. Part 1. Calibration and testing of a Cr-in-Cpx barometer and an enstatite-in-Cpx thermometer. Contributions to Mineralogy and Petrology, 139(5): 541–554. https://doi.org/10.1007/s004100000156

Nimis, P. and Ulmer, P., 1998. Clinopyroxene geobarometry of magmatic rocks. 1. An expanded structural geobarometer for anhydrous and hydrous, basic and ultrabasic systems. Contributions to Minerology and Petrology, 133(1–2): 122–135. https://doi.org/10.1007/s004100050442

Nisbet, E.‌G. and Pearce, J.‌A., 1977. Clinopyroxene composition in mafic lavas from different tectonic settings, Contributions to Mineralogy and Petrology, 63: 149‌–‌160. https://doi.org/10.1007/BF00398776

Nosova, A.‌A., Sazonova, L.‌V., Narkisova, V.‌V. and Simakin, S.‌G., 2002. Minor elements in clinopyroxene from Paleozoic volcanics of the Tagil island arc in the Central Urals. Geochemistry International, 40(3): 219–232. https://doi.org/10.1134/S0016702910030043

Ottonello, G., 1997. Principles of geochemistry. Columbia University Press, Nw York, USA, 894 pp.

Pearce, J.‌A., 2008. Geochemical. fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust. Lithos, 100 (1–4): 14–48. https://doi.org/10.1016/j.lithos.2007.06.016

Putirka, K., 2008. Thermometers and Barometers for Volcanic Systems. Reviews in Mineralogy and Geochemistry, 69(1): 61–120. https://doi.org/10.2138/rmg.2008.69.3

Putirka, K., Johnson, M., Kinzler, R. and Walker, D., 1996. Thermobarometry of mafic igneous rocks based on clinopyroxene-liquid equilibria, 0-30 kbar. Contributions to Mineralogy and Petrology, 123(1): 92–108. https://doi.org/10.1007/s004100050145

Putirka, K., Mikaelian, H., Ryerson, F. and Shaw, H., 2003. New clinopyroxene-liquid thermobarometers for mafic, evolved, and volatile-bearing lava compositions, with applications to lavas from Tibet and the Snake River Plain, Idaho. American Mineralogist, 88(10): 1542–1554. https://doi.org/10.2138/am-2003-1017

Ross, P. and White, J.D.L., 2006‌. Debris jets in continental phreatomagmatic volcanoes: a field study on their subterranean deposits in the Coombs Hill ventcomplex, Antarctica. Journal of Volcanology and Geothermal Research. 149‌(1–2): 62–84. https://doi.org/10.1016/j.jvolgeores.2005.06.007

Salavati, M. and Fahim Guilany, R., 2014. Petrology and geochemistry of Imam-Zadeh Hashem mafic and ultramafic bodies, southern Guilan province. Journal of Economic Geology, 6‌(1): 87–105. (in Persian with English abstract) http://dx.doi.org/10.22067/ECONG.V6I1.38362

Salehian, Sh., 2011. Study of Petrology and Geochemistry of Mafic Igneous Rocks in Gorgan Shistes. M.Sc. Thesis, Shahroud University of Technology, Shahroud, Iran, 175 pp.

Salehi Rad, M.R., 1979. Etude géologique de la region de Gorgan (Alborz oriental, Iran). Ph.D. Thesis, University of Paris, Paris, France, 162 pp.

Sayari, M., 2012. APG: An efficient software program for Amp-Pl thermobarometry based on graphical method. Journal of Sciences, Islamic Republic of Iran, 22‌(4): 345–349. http://dx.doi.org/10.22059/JSCIENCES.2011.23869

Şengor, A.M.C., 1990. A new model for the late Palaeozoic–Mesozoic tectonic evolution of Iran and implications for Oman. Geological Society of London, 49‌(1): 797–831. http://dx.doi.org/10.1144/gsl.sp.1992.049.01.49

Shahpasand Zadeh, M., 1992. Structural Analysis and Interpretation of Sedimentary Environment of Gorgan. 10th Symposium of Geological Society of Iran, Tarbiat Modarres University, Tehran, Iran.

 Shahpasand Zadeh, M. and Keshavarz, S., 2019. Structural evolution and sedimentary-tectonic analysis of Gorgan schists: remnants of a pre-arc zone or intercontinental palate remnants of Paleo Tethys. 1st National Conference on Geology of Alborz Orogene and Caspian Sea, Golestan University, Gorgan, Iran.

Sinha A.K., 2012. Petrological characterization of Proterozoic mafic dykes from the Singhbhum craton, eastern India, 34th International Geological Congress, University of Queensland, Brisbane, Australia.

Sinha, A.K., 2013. Geochemistry of distinct mafic dykes from the Damodar valley Gondwana basins and Chhotanagpur gneissic terrain, eastern India: implications for their petrogenesis and tectonic setting. 125th anniversary of The Geological Society of America, Cornell University, New York, USA.

Soesoo, A., 1997. A multivariate statistical analysis of clinopyroxene composition: empirical coordinates for the crystallization PT- estimation. Journal of the Geological Society of Sweden, 119‌(1): 55–60. https://doi.org/10.1080/11035899709546454

Soto, J.‌I., 1993. Software for thermobarometry and activity calculations with mafic and ultramafic assemblages. American Mineralogists, 78‌(7–8): 840‌–‌844. https://doi.org/10.1016/0098-3004(94)00101-Y

Spear, F. S., 1995. Metamorphic phase equilibria and pressure - temperature- time paths. Mineralogical Society of American, Washington D.C., USA, 799 pp.

Stampfli, G.M. and Borel, G.D., 2002. A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrones. Earth and Planetary science letters 196 (1–2): 17–33. https://doi.org/10.1016/S0012-821X(01)00588-X

Stöcklin, J., 1968. Structural history and tectonics of Iran: A review. The American Association of Petroleum Geologists Bulletin, 52‌(7): 1229–1258. https://doi.org/10.1306/5D25C4A5-16C1-11D7-8645000102C1865D

Stöcklin, J., 1974. Possible ancient continental margins in Iran. In: C.A. Burk and C.L. Drake (Editors), The geology of continental margins. Springer, New York, pp. 873–887. https://doi.org/10.1007/978-3-662-01141-6_64

Winchester, J.A. and Floyd, P.A., 1977. Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology, 20‌(1): 325–343. https://doi.org/10.1016/0009-2541(77)90057-2