Mineral chemistry and thermobarometry of Eocene alkaline volcanic rocks in SW Germi, NW Iran

Iranian Journal of Earth Sciences

مقاله 5، دوره 10، شماره 1، تیر 2018، صفحه 39-51   

نوع مقاله: Original Research Paper

نویسندگان

Mohammad Mobashergermi¹؛ Reza Zarei Sahamieh^{* 2}؛ Mehraj Aghazadeh³؛ Ahmad Ahmadikhalaj⁴؛ Gholamreza Ahmadzadeh⁵

¹Department. Of Geology, Faculty of science, Lorestan University, Iran

²Department. Of Geology, Faculty of science, Lorestan University, Iran.

³Department of Geology, Payame Noor University, Iran.

⁴Department. Of Geology, Faculty of science, Lorestan University

⁵3. Department of Geology, Mohaghegh Ardabil University, Iran

چکیده

Petrography and chemistry of minerals showing that Eocene alkaline volcanic rocks in southwestern of Germi (Talesh zone, NW Iran) mostly have basaltic composition. Mineralogically these rocks are composed of diopsidic clinopyroxene and labradoritic plagioclase phenocrysts. The microlithic and glassy groundmass composed of sanidine, clinopyroxene, biotite, pargasitic amphibole and magnetite associated with devitrified glass. Clinopyroxenes show relatively high Mg-numbers (0.76-0.93), low Al^VI (mostly <0.1), suggesting relatively low-pressure (~5), and water content ~2.5 to less than 10% and high oxygen fugacity (-8.38-11.51) of crystallization condition. High amount existence of magnetite coexisting with amphibole and biotite mineral confirm high fugacity of the host magma. According to clinopyroxene and feldspar thermometry, estimated crystallization temperature varies between 1106˚C to ~1200 ˚C. The clinopyroxene and amphibole mineral composition of studied rocks indicate that they have been formed in a back-arc basin environment. Mineral chemistry in the current zone shows that composition and genesis of common minerals these magmatic rocks are similar to Pushtasar basaltic rocks in the northern part of this area.

کلیدواژه‌ها

Mineral chemistry؛ Thermobarometry؛ Clinopyroxene؛ Eocene alkaline rocks؛ NW Iran

مراجع

1. Abdel Rahman AM (1994) Nature of biotites from alkaline, calc-alkaline and per aluminous magmas. Journal of Petrology 35: 525-541.
2. Aghazadeh M, Castro A, Badrzadeh Z, Vogt K (2011) Post-collisional polycyclic plutonism from the Zagros hinterland. The Shaivar-Dagh plutonic complex Alborz belt, Iran. Geological Magazine 148: 980-1008.
3. Aghazadeh M, Castro A, Omrani N R, Emami M H, Moinevaziri H, Badrzadeh Z (2010) The gabbro (shoshonitic)-monzonite-granodiorite association of Khankandi pluton, Alborz mountains, NW Iran. Journal of Asian Earth Sciences 38: 199-219.
4. Anderson LJ (1996) Status of thermobarometry in granitic batholiths. Geological Society of America Special Papers 315: 125-138.
5. Aoki K, Shiba I (1973) Pyroxenes from lherzolite inclusions of Itinomegata-Gata, Japan. Lithos 6: 41-51.
6. Avanzinelli R, Bindi L, Menchetti S, Conticelli S (2004) Crystallization and genesis of per alkaline magmas from Pantelleria volcano, Italy: an integrated petrological and crystal-chemical. Lithos 73(1–2): 41-69.
7. Babakhani AR, KhanNazer H (1997) Geological Quadrangle Map and repot 1:100000 Lahrud, No.5567. Geological Survey of Iran (in Persian).
8. Beane RE (1974) Biotite stability in the porphyry copper environment. Economic Geology 69: 241-256.
9. Beccaluva L, Macciotta G, Piccardo GB, Zeda O (1989) Clinopyroxene composition of ophiolite basalts as petrogenetic indicator. Chemical Geology 77: 165-182.
10. Berberian F, Berberian M (1981) Tectono-plutonic episodes in Iran. American Geophysical Union. Geodynamics Series 3: 5-32.
11. Berman R (1988) Internally consistent thermodynamic data for minerals in the system Na₂O-K₂O-CaO-MgO-FeO-Fe₂O₃- Al₂O₃-SiO₂-TiO₂-H₂O-CO₂. Journal of Petrology 29: 445-522.
12. Bindi L, Cellai D, Melluso L, Conticelli S, Morra V, Menchetti S (1999) Crystal chemistry of clinopyroxene from alkaline undersaturated rocks of the Monte Vulture volcano, Italy. Lithos 46: 259-274.
13. Botcharnikov R, Koepke J, Holtz F, McCammon C, Wilke M (2005) The effect of water activity on the oxidation and structural state of Fe in a Ferro-basaltic melt. Geochimica et Cosmochimica Acta 69: 5071-5085.
14. Brunet MF, Korotaevb MV, Ershovb AV, Nikishinb AM (2003) The South Caspian Basin: a review of its evolution from subsidence modeling. Sedimentary Geology 156: 119-148.
15. Castro A, Aghazadeh M, Badrzadeh Z, Chichorro M (2013) Late Eocene-Oligocene post-collisional monzonitic intrusions from the Alborz magmatic belt, NW Iran. An example of monzonite magma generation from a metasomatized mantle source. Lithos 181: 109-127.
16. Castro A, Stephen WE (1992) Amphibole rich clots in calcalkalin granitic rocks and their enclaves. The Canadian Mineralogist 30: 1093-1112.
17. Coltorti M, Bonadiman C, Faccini B, Grégoire M, O`Reilly S Y, Powell W (2007) Amphiboles from suprasubduction and intraplate lithospheric mantle. Lithos 99: 68-84.
18. Deer WA, Howie R A, Zussman J (1992) An Introduction to the rock-forming minerals. Longman 528p.
19. France L, Ildefonse B, Koepke J, Bech F (2010) A new method to estimate the oxidation state of basaltic series from microprobe analyses. Journal of Volcanology and Geothermal Research 189: 340-346.
20. France L, Koepke J, Ildefonse B, Cichy SB, Deschamps F (2010) Hydrous Partial Melting in the Sheeted Dike Complex at Fast Spreading Ridges: Experimental and Natural Observations. Contributions to Mineralogy and Petrology 160: 683-704.
21. Gasparik T (1984) Two-pyroxene thermobarometry with new experimental data in the system CaO-MgO, Al₂O₃-SiO₂. Contributions to Mineralogy and Petrology 87: 87-97.
22. Gioncada A, Hauser N, Matteini M, Mazzuolir M, Omarini R (2006) Mingling and mixing features in basaltic andesites of the eastern Cordillera (central Andes, 24S): a petrographic and microanalytical study. Periodico di Mineralogia 75(3): 127-140.
23. Hammarstrom A, Jane M, Zen EA (1986) Aluminum in hornblende: An empirical igneous geobarometer. American Mineralogist 71: 1297-1313.
24. Helz RT (1976) Phase relations of basalts in their melting ranges at P_H2O= 5 kbar: Part melt compositions. Journal of Petrology 17: 139-193.
25. Hendry DA, Chivas AR, Long JVP, Reed SJB (1985) Chemical differences between minerals from mineralizing and barren intrusions from some North American prophyry copper deposits. Contributions to Mineralogy and Petrology 89: 317-329.
26. Huot F, Hébert R, Varfalvy V, Beaudoin G, Wang C, Liu Z, Cotten J, Dostal J (2002) The Beimarang mélange (southern Tibet) brings additional constraints in assessing the origin, metamorphic evolution and obduction processes of the Yarlung Zangbo ophiolite. Journal of Asian Earth Sciences 21(3): 307-322.
27. Kroll H, Evangelakakis C, Voll G (1993) Two-feldspar geothermometery: A review and revision for slowly cooled rocks. Contributions to Mineralogy and Petrology 114: 510-518.
28. Kuscu GG, Floyd P (2001) Mineral compositional and textural evidence for magma mingling in the Saraykent volcanic rocks. Lithos 56: 207-230.
29. Kushiro I (1960) Si-Al Relation in clinopyroxenes from igneous rocks. American Journal of Science 258: 548-554.
30. LeBass NJ (1962) The role of aluminous in igneous clinopyroxenes and plagioclase with relation to their parentage. American Journal of earth Science 260: 267 - 88.
31. Leterrier J, Maurry RC, Thonon P, Girard D, Marchal M (1982) Clinopyroxene composition as a method of identification of the magmatic affinites of paleo-volcanic series. Earth and Planetary Science Letters 59: 139-154.
32. Manoli S, Molin G (1988) Crystallographic procedures in the study of experimental rocks: X-ray single-crystal structure refinement of clinopyroxene from Lunar 74275 high-pressure experimental basalt. Mineralogy and petrology 39: 187-200.
33. Masson F, Djamour Y, Van Gorp S, Chéry J, Tavakoli F, Nankali H, Vernant P (2006) Extension in NW Iran driven by the motion of the south Caspian basin. Earth and Planetary Science Letters 252: 180-188.
34. Mobashergermi M (2013) Petrology, petrography and geochemical studies of basaltic rocks in Southwest of Germi (Ardabil province). MSc thesis, Department of Geology, University of Tabriz, Tabriz, Iran (in Persian).
35. Mobashergermi M, Akbari Z, Jamshedibadr M (2015) Geochemistry, petrogeneses and origin magmatic evolution in the olivine gabbro dikes in Southwest of Germi city. Journal of Petrology 6(20): 65-86 (in Persian).
36. Mobashergermi M, Zaraisahameh, R, Jahangeri A, (2015) Petrography and mineral chemistry of basaltic Prisms in south of Germi city, Pushtasar axis (South talesh). Journal of new findings in geology practical 6(20): 65-86 (in Persian).
37. Molina J, Scarrow J, Montero PG, Bea F (2009) High-Ti amphibole as a petrogenetic indicator of magma chemistry: evidence for mildly alkalic-hybrid melts during evolution of Variscan basic-ultrabasic magmatism of central Iberia. Contribution to Mineralogy and Petrology 158: 69-98.
38. Morimoto N, Fabrise J, Ferguson A, Ginzburg IV, Ross M, Seifert FA, Zussman J, Akoi KI, Gottardi G (1988) Nomenclature of pyroxenes. Mineralogical Magazine 52: 535 -55.
39. Papike JJ, Cameron M (1976) Crystal chemistry of silicate minerals of geophysical interest. Reviews of Geophysics 14: 37-80.
40. Perugini D, Poli G, Valentini L (2005) strange attractors in plagioclase oscillatory zoning petrological implications. Contributions to Mineralogy and Petrology 149: 482-497.
41. Princivalle F, Tirone M, Comin-Chiaramonti P (2000) Clinopyroxenes from metasomatized spinel-peridotite mantle xenoliths from Nemby (Paraguay): crystal chemistry and petrological implications. Mineralogy and Petrology 70: 25-35.
42. Schmidt MW (1992) Amphibole composition in tonalite as a function of pressure: an experimental calibration of the Al in hornblende barometer, Contributions to mineralogy and Petrology 110: 304 -310.
43. Schweitzer E, Papike J, Bence A (1979) Statistical analysis of clinopyroxenes from deep-sea basalts. American Mineralogist 64: 501-513.
44. Soesoo A (1997) A multivariate statistical analysis of clinopyroxene composition: empirical coordinates for the crystallization PT-estimations. Geological Society of Sweden. Geologiska Föreningen 119: 55-60.
45. Stein E, Dietl C (2001) Hornblende thermobarometry of granitoids from the Central Odenwald (Germany) and their implications for the geotectonic development of the Odenwald. Mineralogy and Petrology 72: 185–207.
46. Taylor W, Nimis J (2000) Thermometry clinopyroxene in the Hawaii basalt. Mineralogy 21: 25-36.
47. Vynhal CR, McSween HY, Speer JA (1991) Hornblende chemistry in southern Appalachian granitoids: Implications for aluminum hornblende thermobarometry and magmatic epidote stability. American Mineralogist 76: 176-188.
48. Whitney D L, Evans B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95: 185–187.
49. Wones DR, Eugster HP (1965) Stability of biotite: experiment, theory and application. American Mineralogist 50: 1228-1272.
50. Wones DR, Gilbert MC (1982) Amphiboles in the igneous environment. Mineralogical Society of America Reviews in Mineralogy 9: 355-390.
51. Yoder HS, Tilley GE (1962) Origion of basalt magmas: an experimental study of natural and synthetic rock systems. Journal of Petrology 3: 348-532.
52. Zhu Y, Ogasawara Y (2004) Clinopyroxene phenocrysts (with green salite cores) in, trachybasalts: implications for two magma chambers under the Kokchetav UHP massif, North Kazakhstan. Journal of Asian Earth Sciences 22: 517-527.