Investigations on mineral chemistry and P-T estimation for formation of diopside, garnet and coexisting minerals in the calc- silicate hornfelses from the Alvand metamorphic aureole, Hamadan, West of Iran

Ghorbani, H; Moazzen, M; Saki, A

doi:10.22071/gsj.2017.41049

Document Type : Original Research Paper

Authors

¹ Ph.D. Student, Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

² Professor, Department of Earth Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran

³ Associate Professor, Faculty of Geology, University of Shahid Chamran, Ahvaz, Iran

https://doi.org/10.22071/gsj.2017.41049

Abstract

Calc-silicate hornfelses are resulted from temperature excreted from the Alvand Batholith on the surrounding carbonate rocks. Metamorphic minerals in these rocks are vesuvianite + garnet+clinopyroxene+ tremolite/actinolite+quartz+calcite±epidote. Calc- silicate minerals occurred in two stages of prograde and retrograde metamorphism. Mineral chemistry of clinopyroxene and garnet in calc-silicate hornfelses determined by EPMA shows that these minerals are mainly diopside and grossular. Based on clinopyroxene-garnet thermometry with coexisting minerals such as tremolite/actinolite, quartz, . . . temperature of ~550˚C was calculated for metamorphism of the clac-silicate hornfelses. Pressure of metamorphism was estimated to be about 3.5 Kbar. Fluid composition in the calc- silicate hornfelses had X_CO2 = 0.2 which indicates that during prograde metamorphism carbonate minerals reacted out and the amount of these minerals was reduced in the rocks.

Keywords

20.1001.1.10237429.1395.26.101.16.4

References

Alavi, M., 1994- Tectonics of the Zagros Orogenic belt of Iran: new data and interpretations. Tectonophysics 299: 211-238.

Alavi, M., 2004- Regional stratigraphy of the Zagros Fold-Thrust belt of Iran and its proforelenad evolution”, American Journal of Science 304: 1-20.

Berberian, M. and Berberian, F., 1981- Tectono-Plutonic episodes in Iran. In: Zagros- Hindu Kush- Himalaya Geodynamic Evolution. Geodynamics series, vol. 3, copright by the American Geophysical Union.

Berberian, M. and King, G. C. P., 1981- Towards a paleogeography and tectonic evolution of Iran, Cand. J. Earth. Sci., 18: 210- 265.

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: 431-435.

Ernest, W. G., 1976- Petrologic phase equilibria. W. H. Freeman, San Francisco.

Holland, T. J. B. and Powell, R., 1985- An internally consistent thermodynamic data set with uncertainties and correlations: 2 Data and results. Journal of Metamorphic Geology, 3(4): 343-370.

Mohajjel, M., Fergusson, C. L. and Sahandi, M. R., 2003- Cretaceous- Tertiary convergence and continental, Sanandaj- Sirjan Zone, western Iran, J. Asian Earth Sci, 21: 397 – 412.

Morimoto, N. and Kitamara, M,. 1988- Q-J diagram for classification of pyroxenes. Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologist, 78: 141. (in Japanese).

Saki, A., 2011- Formation of Spinel- cordierite- plagioclase symplectites replacing andalusite in metapelitic of the Alvand aureole, Iran, Geological Magazine 148: 423- 434.

Saki, A., Moazzen, M. and Baharifar, A. A., 2012- Migmatite microstructures and partial melting of Hamadan metapelitic rocks within the Alvand contact aureole, western Iran, International Geology Review in press.

Sepahi, A. A., 2008- Typology and petrogenesis of granitic rocks in the Sanandaj-Sirjan metamorphic belt, Iran”: With emphasis on the Alvand plutonic complex, N. Jb. Geol. Palaton. Abn, 247: 295-312.

Sepahi, A. A., Whitney, D. L. and Baharifar, A. A., 2004- Petrgenesis of And-Ky-Sil veins and host rocks, Sanadaj- Sirjan metamorphic belt, Hamadan, Iran, Jpurnal of Metamorphic Geology 22: 119- 134.

Shahbazi, H., Siebel, W., Pourmoafee, M., Ghorbani, M., Sepahi, A. A., Shang, C. K. and Vousoughi Abedini, M., 2010- Geochemistry and U-Pb zircon geochronology of the Alvand plutonic complex in Sanandaj- Sirjan (Iran): New evidence for Jurassic magmatism. Journal of Asian Earth Sciences, in press.

Valizadeh, M. V. and Cantagrel, J. M., 1975- Premieres donnees radiometriques (K-Ar et Rb-Sr) sur les mica du complexe magmatique du Mont Alvand pres Hamadan (Iran Occidental), Comptes Rendus Hebdomadaires des Seances de l’ Academie des Sciences, Serie D. Sciences Naturelles 281: 1083- 1086.

Whitney, D. L. and Evans, B. W., 2010- Abbreviation for names of rock – forming. Minerals. American mineralogist, volume 95: 185-187

Scientific Quarterly Journal of Geosciences

Investigations on mineral chemistry and P-T estimation for formation of diopside, garnet and coexisting minerals in the calc- silicate hornfelses from the Alvand metamorphic aureole, Hamadan, West of Iran

References

References

Volume 26, Issue 101 - Serial Number 101
VOL.26, NO101
December 2017
Pages 139-146

Investigations on mineral chemistry and P-T estimation for formation of diopside, garnet and coexisting minerals in the calc- silicate hornfelses from the Alvand metamorphic aureole, Hamadan, West of Iran

References

References

Volume 26, Issue 101 - Serial Number 101VOL.26, NO101December 2017Pages 139-146

Volume 26, Issue 101 - Serial Number 101
VOL.26, NO101
December 2017
Pages 139-146