الگوی دما- فشار فرآیند تشکیل اکلوژیت‌های مجموعه‌ی دگرگونی شفارود در زیرپهنه‌ی تالش در شمال‌غرب ایران با استفاده از گارنتهای منطقه‌بندی‌شده

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده زمین‌شناسی، دانشگاه هرمزگان، بندرعباس، ایران

2 دانشکده زمین‌شناسی، دانشگاه زنجان، زنجان، ایران

چکیده

مجموعه‌ی دگرگونی شفارود در شمال‌غرب ایران در پهنه‌ی کوهستانی البرز- تالش قرار دارد. مجموعه‌ی دگرگونی پالئوزوئیک (کربونیفر- پرمین) قدیمی‌ترین سنگ‌های این منطقه هستند. اکلوژیت‌های مجموعه‌ی دگرگونی شفارود به‌صورت عدسی‌های چند متری به‌همراه توده‌های سرپانتنیتی در بخش‌های قاعده‌ای رخنمون دارند. مجموعه کانی‌های تشکیل‌دهنده‌ی اکلوژیت شامل گارنت، پیروکسن، آمفیبول، میکای سفید، اپیدوت، پلاژیوکلاز، کلریت، کوارتز و اسفن است. تصاویر میکروسکوپ الکترونی و نتایج تجزیه‌ی شیمیایی با ریز پردازنده‌ی الکترونی (EPMA) ساختار منطقه‌بندی شیمیایی رشدی در شکفته بلور‌های گارنت را نشان می‌دهند. براساس محاسبه‌ی الگوی دما- فشار با استفاده از تبدیل ژاکوبین، مرکز‌ و لبه گارنت‌ها به‌ترتیب در دما- فشار  kbar2/18 -Cº ٦00 (رخساره‌ی اکلوژیتی، حدود  km60) و‌ kbar 5/7 -Cº 550 (رخساره‌ی شیست سبز، حدود km25) تشکیل شده‌اند. برپایه نتایج بررسی­ها، الگوی ساختاری برای تحلیل اکلوژیت‌های مجموعه‌ی دگرگونی شفارود شبیه نوع آلپی بوده که طی آن، فرآیند بالاآمدگی و کاهش فشار در شرایط تقریباً هم‌دما به‌دلیل یک بالاآمدگی سریع رخ داده‌است.    

کلیدواژه‌ها

عنوان مقاله [English]

P-T pattern of eclogite formation of the Shafarud Metamorphic Complex in the Talesh subzone, NW Iran using zoned garnets

نویسندگان [English]

  • Nazila Nasihatsheno 1
  • Seyedmohsen Mortazavi 1
  • javad Izadyar 2
1 Department of Geology, University of Hormozgan, Bandarabbas, Iran
2 Department of Geology, Faculty of Sciences, University of Zanjan, Zanjan, Iran
چکیده [English]

The Shafarud Metamorphic Complex is located in the northwestern part of Iran in the Alborz-Talesh Mountain range. Paleozoic metamorphism (Carboniferous-Permian) are the oldest rocks of this region. The eclogites of the Shafarud Metamorphic Complex are exposed as lenses of several meters in size along with serpentinite masses in the basal parts. The mineral assemblage of the eclogites includes garnet, pyroxene, amphibole, white mica, epidote, plagioclase, chlorite, quartz and sphene. SEM images and the results of electron probe micro-analyzer (EPMA) show the growth chemical zoning in garnet porphyroblasts. According to the calculation of the temperature-pressure pattern, using Jacobian transformation, the core and the rim of garnets have been formed respectively at temperature-pressure 600 ºC -18.2 Kbar (eclogite facies, ~60 Km) and 550 ºC- 7.5 Kbar (green schist facies, ~25 Km). According to the results of this study, the structural pattern of the eclogites of the Shafarud Metamorphic Complex is similar to the alpine type, during which the process of uplift and pressure reduction occurred in almost isothermal conditions due to a rapid uplift.

کلیدواژه‌ها [English]

  • Talesh
  • Shafarud Metamorphic Complex
  • garnet
  • temperature-pressure pattern

مراجع

  1. [1] Likhanov I. I., "Metamorphic indicators for collision, extension, and shear zone geodynamic settings of the Earth's crust", Petrology 28 (2020) 1-16. [DOI:10.1134/S086959112001004X]
  2. [1] Likhanov I. I., "Metamorphic indicators for collision, extension, and shear zone geodynamic settings of the Earth's crust", Petrology 28 (2020) 1-16. [DOI:10.1134/S086959112001004X]
  3. [2] Powell R., Holland T. J. B. H., Worley B., "Calculating phase diagrams involving solid solutions via non‐linear equations, with examples using THERMOCALC", Journal of metamorphic Geology 16.4 (1998) 577-588. [DOI:10.1111/j.1525-1314.1998.00157.x]
  4. [2] Powell R., Holland T. J. B. H., Worley B., "Calculating phase diagrams involving solid solutions via non‐linear equations, with examples using THERMOCALC", Journal of metamorphic Geology 16.4 (1998) 577-588. [DOI:10.1111/j.1525-1314.1998.00157.x]
  5. [3] Tracy R. J., "Compositional zoning and inclusions in metamorphic minerals,"Characterization of metamorphism through mineral equilibria", De Gruyter (2018) 354-398. [DOI:10.1515/9781501508172-013]
  6. [3] Tracy R. J., "Compositional zoning and inclusions in metamorphic minerals,"Characterization of metamorphism through mineral equilibria", De Gruyter (2018) 354-398. [DOI:10.1515/9781501508172-013]
  7. [4] Etzel T. M., Elizabeth J. C., "Garnet Chemical Zoning Based Thermobarometry: Method Evaluation and Applications in the Menderes Massif, Western Turkey", Geosciences 11.12 (2021) 505. [DOI:10.3390/geosciences11120505]
  8. [4] Etzel T. M., Elizabeth J. C., "Garnet Chemical Zoning Based Thermobarometry: Method Evaluation and Applications in the Menderes Massif, Western Turkey", Geosciences 11.12 (2021) 505. [DOI:10.3390/geosciences11120505]
  9. [5] Hickmott D. D., "Trace element zoning in garnets--implications for metamorphic petrogenesis", Doctoral dissertation, Massachusetts Institute of Technology (1988).
  10. [5] Hickmott D. D., "Trace element zoning in garnets--implications for metamorphic petrogenesis", Doctoral dissertation, Massachusetts Institute of Technology (1988).
  11. [6] Hickmott D., Spear F.S., "Major-and trace-element zoning in garnets from calcareous pelites in the NW Shelburne Falls Quadrangle, Massachusetts: garnet growth histories in retrograded rocks", Journal of Petrology 33.5 (1992) 965-1005. [DOI:10.1093/petrology/33.5.965]
  12. [6] Hickmott D., Spear F.S., "Major-and trace-element zoning in garnets from calcareous pelites in the NW Shelburne Falls Quadrangle, Massachusetts: garnet growth histories in retrograded rocks", Journal of Petrology 33.5 (1992) 965-1005. [DOI:10.1093/petrology/33.5.965]
  13. [7] Kohn M.J., Valley J.W., Elsenheimer D., Spicuzza M.J., "O isotope zoning in garnet and staurolite: evidence for closed-system mineral growth during regional metamorphism", American Mineralogist 78, no. 9-10 (1993) 988-1001.
  14. [7] Kohn M.J., Valley J.W., Elsenheimer D., Spicuzza M.J., "O isotope zoning in garnet and staurolite: evidence for closed-system mineral growth during regional metamorphism", American Mineralogist 78, no. 9-10 (1993) 988-1001.
  15. [8] Spear F. S., "Metamorphic phase equilibria and pressure-temperature-time paths", Mineralogical Society of America Monograph (1993) 352-356.
  16. [8] Spear F. S., "Metamorphic phase equilibria and pressure-temperature-time paths", Mineralogical Society of America Monograph (1993) 352-356.
  17. [9] Spear F. S., "Phase equilibria of amphibolites from the Post pond Volcanics, Mt. Cube quadrangle, Vermont", Journal of Petrology 23.3 (1982) 383-426. [DOI:10.1093/petrology/23.3.383]
  18. [9] Spear F. S., "Phase equilibria of amphibolites from the Post pond Volcanics, Mt. Cube quadrangle, Vermont", Journal of Petrology 23.3 (1982) 383-426. [DOI:10.1093/petrology/23.3.383]
  19. [10] Spear F. S., "Metamorphic fractional crystallization and internal metasomatism by diffusional homogenization of zoned garnets", Contributions to Mineralogy and Petrology 99.4 (1988) 507-517. [DOI:10.1007/BF00371941]
  20. [10] Spear F. S., "Metamorphic fractional crystallization and internal metasomatism by diffusional homogenization of zoned garnets", Contributions to Mineralogy and Petrology 99.4 (1988) 507-517. [DOI:10.1007/BF00371941]
  21. [11] De Capitani C., Petrakakis K., "The computation of equilibrium assemblage diagrams with Theriak/Domino software", American mineralogist 95.7 (2010) 1006-1016. [DOI:10.2138/am.2010.3354]
  22. [11] De Capitani C., Petrakakis K., "The computation of equilibrium assemblage diagrams with Theriak/Domino software", American mineralogist 95.7 (2010) 1006-1016. [DOI:10.2138/am.2010.3354]
  23. [12] Spear F. S., Peacock S. M., Kohn M. J., Florence F. P., Menard T., "Computer programs for petrologic PTt path calculations", American Mineralogist 76.11-12 (1991) 2009-2012.
  24. [12] Spear F. S., Peacock S. M., Kohn M. J., Florence F. P., Menard T., "Computer programs for petrologic PTt path calculations", American Mineralogist 76.11-12 (1991) 2009-2012.
  25. [13] Konrad-Schmolke M., Handy M.R., Babist J., O'Brien P.J., "Thermodynamic modelling of diffusion-controlled garnet growth", Contributions to Mineralogy and Petrology 149 (2005) 181-195. [DOI:10.1007/s00410-004-0643-6]
  26. [13] Konrad-Schmolke M., Handy M.R., Babist J., O'Brien P.J., "Thermodynamic modelling of diffusion-controlled garnet growth", Contributions to Mineralogy and Petrology 149 (2005) 181-195. [DOI:10.1007/s00410-004-0643-6]
  27. [14] Gaidies F., De Capitani C., Abart R., Schuster R., "Prograde garnet growth along complex P-T-t paths: results from numerical experiments on polyphase garnet from the Wölz Complex (Austroalpine basement)", Contributions to Mineralogy and Petrology 155 (2008) 673-688. [DOI:10.1007/s00410-007-0264-y]
  28. [14] Gaidies F., De Capitani C., Abart R., Schuster R., "Prograde garnet growth along complex P-T-t paths: results from numerical experiments on polyphase garnet from the Wölz Complex (Austroalpine basement)", Contributions to Mineralogy and Petrology 155 (2008) 673-688. [DOI:10.1007/s00410-007-0264-y]
  29. [15] Gulbin Yu L. "Optimization of the garnet-biotite geothermometer. Temperature trends", Geology of Ore Deposits 53 (2011) 528-557. [DOI:10.1134/S1075701511070087]
  30. [15] Gulbin Yu L. "Optimization of the garnet-biotite geothermometer. Temperature trends", Geology of Ore Deposits 53 (2011) 528-557. [DOI:10.1134/S1075701511070087]
  31. [16] Spear F. S., Selverstone J., "Quantitative PT paths from zoned minerals: theory and tectonic applications", Contributions to Mineralogy and Petrology 83.3-4 (1983) 348-357. [DOI:10.1007/BF00371203]
  32. [16] Spear F. S., Selverstone J., "Quantitative PT paths from zoned minerals: theory and tectonic applications", Contributions to Mineralogy and Petrology 83.3-4 (1983) 348-357. [DOI:10.1007/BF00371203]
  33. [17] Alavi M., "Tectonostratigraphic synthesis and structural style of the Alborz mountain system in northern Iran", Journal of Geodynamics 21.1 (1996) 1-33. [DOI:10.1016/0264-3707(95)00009-7]
  34. [17] Alavi M., "Tectonostratigraphic synthesis and structural style of the Alborz mountain system in northern Iran", Journal of Geodynamics 21.1 (1996) 1-33. [DOI:10.1016/0264-3707(95)00009-7]
  35. [18] Asadian Q., Mirzaee A. R., Eftekhar Nezhad j., "Geology map and Explanatory Text of the Khalkhal-Rezvanshahr Quadrangle Map (in Persian)", Geological Survey of Iran, scale 1:100,000 (1998) series sheet 5765.
  36. [18] Asadian Q., Mirzaee A. R., Eftekhar Nezhad j., "Geology map and Explanatory Text of the Khalkhal-Rezvanshahr Quadrangle Map (in Persian)", Geological Survey of Iran, scale 1:100,000 (1998) series sheet 5765.
  37. [19] Holland T., Powell R., "AX-Activity-Composition Software", Department of Earth Sciences, University of Cambridge, Cambridge UK (2005).
  38. [19] Holland T., Powell R., "AX-Activity-Composition Software", Department of Earth Sciences, University of Cambridge, Cambridge UK (2005).
  39. [20] Powell R., Holland T. J. B., "An internally consistent dataset with uncertainties and correlations: 3. Applications to geobarometry, worked examples and a computer program", Journal of metamorphic Geology, 6.2 (1988) 173-204. [DOI:10.1111/j.1525-1314.1988.tb00415.x]
  40. [20] Powell R., Holland T. J. B., "An internally consistent dataset with uncertainties and correlations: 3. Applications to geobarometry, worked examples and a computer program", Journal of metamorphic Geology, 6.2 (1988) 173-204. [DOI:10.1111/j.1525-1314.1988.tb00415.x]
  41. [21] Whitney D. L., Evans B. W., "Abbreviations for names of rock-forming minerals", American mineralogist, 95(1) (2010) 185-187. [DOI:10.2138/am.2010.3371]
  42. [21] Whitney D. L., Evans B. W., "Abbreviations for names of rock-forming minerals", American mineralogist, 95(1) (2010) 185-187. [DOI:10.2138/am.2010.3371]
  43. [22] Coleman R. G., Lee D. E., Beatty L. B., Brannock W. W., "Eclogites and eclogites: their differences and similarities", Geological Society of America Bulletin, 76(5) (1965) 483-508. [DOI:10.1130/0016-7606(1965)76[483:EAETDA]2.0.CO;2]
  44. [22] Coleman R. G., Lee D. E., Beatty L. B., Brannock W. W., "Eclogites and eclogites: their differences and similarities", Geological Society of America Bulletin, 76(5) (1965) 483-508. [DOI:10.1130/0016-7606(1965)76[483:EAETDA]2.0.CO;2]
  45. [23] Kohn M. J., "Geochemical Zoning in Metamorphic", Crust 3 (2005) 229. [DOI:10.1016/B0-08-043751-6/03176-5]
  46. [23] Kohn M. J., "Geochemical Zoning in Metamorphic", Crust 3 (2005) 229. [DOI:10.1016/B0-08-043751-6/03176-5]
  47. [24] Faryad S.W., Nahodilová R., Dolejš D., "Incipient eclogite facies metamorphism in the Moldanubian granulites revealed by mineral inclusions in garnet", Lithos 114.1-2 (2010) 54-69. [DOI:10.1016/j.lithos.2009.07.014]
  48. [24] Faryad S.W., Nahodilová R., Dolejš D., "Incipient eclogite facies metamorphism in the Moldanubian granulites revealed by mineral inclusions in garnet", Lithos 114.1-2 (2010) 54-69. [DOI:10.1016/j.lithos.2009.07.014]
  49. [25] Ernst W. G., "Tectonic history of subduction zones inferred from retrograde blueschist PT paths", Geology 16.12 (1988) 1081-1084.

    https://doi.org/10.1130/0091-7613(1988)0162.3.CO;2 [DOI:10.1130/0091-7613(1988)0162.3.CO;2]
  50. [25] Ernst W. G., "Tectonic history of subduction zones inferred from retrograde blueschist PT paths", Geology 16.12 (1988) 1081-1084.

    https://doi.org/10.1130/0091-7613(1988)0162.3.CO;2 [DOI:10.1130/0091-7613(1988)0162.3.CO;2]

فایل ها

سابقه مقاله

  • تاریخ دریافت: 17 تیر 1402
  • تاریخ بازنگری: 12 مرداد 1402
  • تاریخ پذیرش: 04 شهریور 1402

هم رسانی

ارجاع به این مقاله

آمار