Chemical compositions and optical characters of sodic–calcic and calcic amphiboles in basic schists of Shahneshin area, southwest of Zanjan

Document Type : Original Article

Authors

Abstract

Shahneshin area is located in southwest of Zanjan at the border between Zanjan and Kurdestan provinces. Based on petrographic investigation, Shahneshin basic schists could be divided into actinolite schist, actinolite pyroxene schist, actinolite pyroxene garnet schist and actinolite epidote schist. Actinolite schists are the most abundant rocks among basic schists and are composed of amphibole, muscovite, chlorite and albite as major minerals. Amphiboles occurred in two different fabric including inclined and parallel to the main schistosity. Optical characters of amphibole changes from core towards rim in which birefringence and extinction angle decrease and ppl color changes from green-blue to the pale green. In the other hand, chemical analysis of the same amphibole from core towards rim shows that core has richerite-winchite composition while rim has actinolite composition. Therefore, there is clear relation between optical and chemical characters in which reverse glaucophane substitution (CaM4 MgOctAlOct) and plagioclase substitution (CaM4 AlT) occurred. P-T calculation using chemical composition of amphibole cores show that they formed under 14 kbar pressure and 440 OC temperature while their rims formed under pressure of 4 kbar and temperature of 520 OC. Thus optical and chemical zoning observed in amphiboles in Shahneshin basic schists could be formed due to changes in pressure and temperature of the metamorphism.

Keywords

References

  1. [1] Hawthorne, F.C. and Veblen, D.R., "Amphiboles and other hydrous pyriboles-mineralogy", Reviews in Mineralogy (1981) 1-102. [DOI:10.1515/9781501508219-005]
  2. [1] Hawthorne, F.C. and Veblen, D.R., "Amphiboles and other hydrous pyriboles-mineralogy", Reviews in Mineralogy (1981) 1-102. [DOI:10.1515/9781501508219-005]
  3. [2] Veblen D. R., & Ribbe P. H. "Amphiboles: Petrology and experimental phase relation", Reviews in Mineralogy (1982) 390p. [DOI:10.1515/9781501508196]
  4. [2] Veblen D. R., & Ribbe P. H. "Amphiboles: Petrology and experimental phase relation", Reviews in Mineralogy (1982) 390p. [DOI:10.1515/9781501508196]
  5. [3] Gilbert M. C., Helz R. T., Popp R. K., Spear F. S., Veblen D. R., Ribbe, P. H., "Amphiboles: petrology and experimental phase relations", MSA Reviews in Mineralogy 9 (1982) 231-267.
  6. [3] Gilbert M. C., Helz R. T., Popp R. K., Spear F. S., Veblen D. R., Ribbe, P. H., "Amphiboles: petrology and experimental phase relations", MSA Reviews in Mineralogy 9 (1982) 231-267.
  7. [4] Deer W.A., Howher. a., Zussman. J., "An introduction to the rock forming minerals", Longman Scientific and Technical, England (1992) 581p.
  8. [4] Deer W.A., Howher. a., Zussman. J., "An introduction to the rock forming minerals", Longman Scientific and Technical, England (1992) 581p.
  9. [5] Spear F.S., "Metamorphic phase equilibria and pressure- temperature- time path", Mineralogical Society of America, Washington (1995) 799p.
  10. [5] Spear F.S., "Metamorphic phase equilibria and pressure- temperature- time path", Mineralogical Society of America, Washington (1995) 799p.
  11. [6] Izadyar J., "Optical characters, chemical composition and formation mechanism of colorless sodic and sodic-calcic amphiboles in piemontite-quartz schists from high P-low T Sanbagawa metamorphic belt in central Shikoku, Japan", Iranian Journal of Crystallography and Mineralogy 13(1) (2005) 135-154 (in Persian).
  12. [6] Izadyar J., "Optical characters, chemical composition and formation mechanism of colorless sodic and sodic-calcic amphiboles in piemontite-quartz schists from high P-low T Sanbagawa metamorphic belt in central Shikoku, Japan", Iranian Journal of Crystallography and Mineralogy 13(1) (2005) 135-154 (in Persian).
  13. [7] Nasrabadi M., Roseti F., Moein vVaziri H., Razavi M. H., Mojalal M., "Mineralogy and thermobarometery of blueschists from Soltan Abad metamorphic complex (NE Sabzevar)", Iranian Journal of Crystallography and Mineralogy 20(1) (2013) 123-140 (in Persian).
  14. [7] Nasrabadi M., Roseti F., Moein vVaziri H., Razavi M. H., Mojalal M., "Mineralogy and thermobarometery of blueschists from Soltan Abad metamorphic complex (NE Sabzevar)", Iranian Journal of Crystallography and Mineralogy 20(1) (2013) 123-140 (in Persian).
  15. [8] Nasrabadi M., Gholizadeh K., "Thermobarometry and tectonic setting of metamorphic rocks from the ophiolitic complex of north Torbat-E-Heidarieh", Iranian Journal of Crystallography and Mineralogy 24(2) (2016) 355-370 (in Persian).
  16. [8] Nasrabadi M., Gholizadeh K., "Thermobarometry and tectonic setting of metamorphic rocks from the ophiolitic complex of north Torbat-E-Heidarieh", Iranian Journal of Crystallography and Mineralogy 24(2) (2016) 355-370 (in Persian).
  17. [9] Hajalioghli R., "Mineral chemistry, P-T and tectonometamorphic evolutions of garnet amphibolites from the Takht-e-Soleyman", Iranian Journal of Crystallography and Mineralogy 25(4) (2018) 749-760 (in Persian). [DOI:10.29252/ijcm.25.4.749]
  18. [9] Hajalioghli R., "Mineral chemistry, P-T and tectonometamorphic evolutions of garnet amphibolites from the Takht-e-Soleyman", Iranian Journal of Crystallography and Mineralogy 25(4) (2018) 749-760 (in Persian). [DOI:10.29252/ijcm.25.4.749]
  19. [10] Hosseini B., Ahmadi A. R., "Structural and thermobarometric investigations of metamorphic rocks in the north of Asadabad (Sanandaj-Sirjan zone)", Iranian Journal of Crystallography and Mineralogy 27(1) (2019) 151-166 (in Persian). [DOI:10.29252/ijcm.27.1.151]
  20. [10] Hosseini B., Ahmadi A. R., "Structural and thermobarometric investigations of metamorphic rocks in the north of Asadabad (Sanandaj-Sirjan zone)", Iranian Journal of Crystallography and Mineralogy 27(1) (2019) 151-166 (in Persian). [DOI:10.29252/ijcm.27.1.151]
  21. [11] Borg I. Y., "Optical properties and cell parameters in the glaucophane-riebeckite series", Contributions to Mineralogy and Petrology 15(1) (1967) 67-92. [DOI:10.1007/BF01167215]
  22. [11] Borg I. Y., "Optical properties and cell parameters in the glaucophane-riebeckite series", Contributions to Mineralogy and Petrology 15(1) (1967) 67-92. [DOI:10.1007/BF01167215]
  23. [12] Holland T. J. B., and Powell R., "An internally consistent thermodynamic data set with uncertainties and correlations: The system Na2O-K2O-CaO-MgO-MnO-FeO-Fe2O3-Al2O3-SiO2-TiO2-C-H2-O2", Journal of Metamorphic Geology 8 (1990) 89-124. [DOI:10.1111/j.1525-1314.1990.tb00458.x]
  24. [12] Holland T. J. B., and Powell R., "An internally consistent thermodynamic data set with uncertainties and correlations: The system Na2O-K2O-CaO-MgO-MnO-FeO-Fe2O3-Al2O3-SiO2-TiO2-C-H2-O2", Journal of Metamorphic Geology 8 (1990) 89-124. [DOI:10.1111/j.1525-1314.1990.tb00458.x]
  25. [13] Fonoudi, M and Sayareh, A.R., "Geology map of Yassoukand (Ghojor) 1:100000" Geological Survey and Mineral Exploration of Iran (2000) (in Persian).
  26. [13] Fonoudi, M and Sayareh, A.R., "Geology map of Yassoukand (Ghojor) 1:100000" Geological Survey and Mineral Exploration of Iran (2000) (in Persian).
  27. [14] Pouromidi A., "Petrography and thermodynamic studying of basic schists from Shahneshin metamorphic complex in north of Yasoukand, southwest of Zanjan", M.Sc. thesis in petrology, University of Zanjan (2016) (in Persian).
  28. [14] Pouromidi A., "Petrography and thermodynamic studying of basic schists from Shahneshin metamorphic complex in north of Yasoukand, southwest of Zanjan", M.Sc. thesis in petrology, University of Zanjan (2016) (in Persian).
  29. [15] Whitney D. L., Evans B. W., "Abbreviations for names of rock-forming minerals", American Mineralogist 95 (2010) 185-187. [DOI:10.2138/am.2010.3371]
  30. [15] Whitney D. L., Evans B. W., "Abbreviations for names of rock-forming minerals", American Mineralogist 95 (2010) 185-187. [DOI:10.2138/am.2010.3371]
  31. [16] Klein C. and Hurlbut Jr C. S., "Manual of Mineralogy. John Wiley & Sons. Inc", New York (1999) 681p.
  32. [16] Klein C. and Hurlbut Jr C. S., "Manual of Mineralogy. John Wiley & Sons. Inc", New York (1999) 681p.
  33. [17] Leak B.E., The IMA Commission., "Nomenclature of amphiboles. Report of the sub-committee on Amphiboles of the international mineralogical Association on New-Minerals and mineral names", Eur J Mineral 9 (1997) 623 -651. [DOI:10.1127/ejm/9/3/0623]
  34. [17] Leak B.E., The IMA Commission., "Nomenclature of amphiboles. Report of the sub-committee on Amphiboles of the international mineralogical Association on New-Minerals and mineral names", Eur J Mineral 9 (1997) 623 -651. [DOI:10.1127/ejm/9/3/0623]
  35. [18] 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]
  36. [18] 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]
  37. [19] Holland T. J., & Richardson S. W., "Amphibole zonation in metabasites as a guide to the evolution of metamorphic conditions", Contributions to Mineralogy and Petrology 70(2) (1979) 143-148. [DOI:10.1007/BF00374442]
  38. [19] Holland T. J., & Richardson S. W., "Amphibole zonation in metabasites as a guide to the evolution of metamorphic conditions", Contributions to Mineralogy and Petrology 70(2) (1979) 143-148. [DOI:10.1007/BF00374442]
Iranian Journal of Crystallography and Mineralogy
Volume 28, Issue 4 - Serial Number 80
December 2020
Pages 845-858

Files

History

  • Receive Date: 31 December 2019
  • Revise Date: 23 January 2020
  • Accept Date: 04 March 2020

Share

How to cite

Statistics