Geochemistry, Mineral Chemistry and Thermobarometry of Boneh-Shorou Amphibolites in Gelmandeh Massive (Saghand-Central Iran)
- 1 Department of Geology, Faculty of Science, Miyane Branch, Islamic Azad University, Miyane, Iran
- 2 Department of Earth and Environmental Sciences, Section for Mineralogy, Petrology and Geochemistry, Ludwig-Maximilians University, Muenchen, Germany
- 3 Department of Petrology and Economic Geology, School of Geosciences, Shahrood University of Technology, Shahrood, Iran
- 4 Department of Geology, Faculty of Science, Science and Research Branch, Islamic Azad University, Tehran, Iran
Abstract
The Gelmandeh Massive is located in the Central part of Iranian Microcontinent. Amphibolitic rocks occupy the main portion of Gelmandeh complex, which consists of hornblendite, garnet amphibolites, and gneiss. Geochemical investigations indicate that the ratio of Eu/Eu* separates samples into two categories: first category with ratio of Eu/Eu* > 1 and the second with ratio of Eu/Eu* < 1, which the former indicates an enriched mantle origin while the latter points to crustal contamination. Generally, amphibolites can be differentiated into two separate series. First series is characterized with calc-alkaline to alkaline composition with enriched mantle origin, and the second one has calc-alkaline to tholeiitic nature and it is of continental type that underwent crustal contamination within subduction zone. The microprobe electron analysis shows that the amphiboles were a member of the calcic group and hastingsite-tschermakite series. Geo-barometric studied and mineral paragenesis show that the metamorphism is of Barovian type with PT condition upto 7 K bar and 580 ° C.
- Haghipour, A., Pelissier, G., Bolourchi, M.H., Valeh, N., Aghanabati, A., Davoudzadeh, M., Stocklin, J., Sluiter, W. and Huber, H. (1970) Geological Map of Ardakan (1/250000). Iranian Geological Survey.
- Babakhani, A.R. and Majidi, J. (1995) Geological Map of Saghand (1/100000). Iranian Geological Survey.
- Ramezani, J. and Tucker, R.D. (2003) The Saghand Region, Central IRAN: U-Pb Geochronology, Petrogensis and Implication for Gondwana Tectonics. American Journal of Science, 303, 622-665. http://dx.doi.org/10.2475/ajs.303.7.622
- Ramezani, J. (1997) Regional Geology, Geochronology and Geochemistry of the Igneous and Metamorphic Rock Suites of the Saghand Area, Central IRAN. Ph.D. Thesis, Washington University, St. Louis, Missouri, 416.
- De la Roche, H., Leterrier, J., Grandclaude, P. and Marchal, M. (1980) A Classification of Volcanic and Plutonic Rocks Using R1-R2 Diagrams and Major Element Analyses—Its Relationships with Current Nomenclature. Chemical Geology, 29, 183-210. http://dx.doi.org/10.1016/0009-2541(80)90020-0
- Pearce, J.A. (1996) A User’s Guide to Basalt Discrimination Diagrams. In: Wyman, D.A., Ed., Trace Element Geochemistry of Volcanic Rocks: Applications for Massive Sulphide Exploration, Geological Association of Canada, Short Course Notes, Vol. 12, 79-113.
- Hastie, A.R. Kerr, A.C. Pearce, J.A. and Mitchell, S.F. (2007) Classification of Altered Volcanic Island Arc Rocks Using Immobile Trace Elements: Development of the Th-Co Discrimination Diagram. Journal of Petrology, 48, 2341-2357. http://dx.doi.org/10.1093/petrology/egm062
- Irvin, T.N. and Baragar, W.R.A. (1971) A Guide to the Chemical Classification of the Common Volcanic Rocks. Canadian Journal of Earth Sciences, 8, 523-548. http://dx.doi.org/10.1139/e71-055
- Thompson, A.B. (1982) Dehydration Melting of Politic Rocks and the Generation of H2O-Undersaturated Granitic Liquids. American Journal of Science, 282, 1567-1595. http://dx.doi.org/10.2475/ajs.282.10.1567
- Wood, D.A. (1980) The Application of a Th-Hf-Ta Diagram to Problems of Tectonomagmatic Classification and to Establishing the Nature of Crustal Contamination of Basaltic Lavas of the British Tertiary Volcanic Province. Earth and Planetary Science Letters, 50, 11-30. http://dx.doi.org/10.1016/0012-821X(80)90116-8
- Harker, A. (1909) The Natural History of Igneous Rocks. Methuen & Co., London.
- Spear, F. (2005) Metamorphic Phase Equilibria and Pressure-Temperature-Time Paths. Department of Earth and Environmental Sciences Rensselaer, Polytechnic Institute Troy, New York, Mineralogical Society of America, Washington DC.