Detection of pressure and temperature in formation of Jandaq ophiolite amphibolites (North-east of Isfahan Province) by using amphibole and plagioclase barometry and thermometry

Abstract

Amphibolites are one of the metamorphic rock units of Jandaq ophiolite and exposed in a considerable volume. These rocks are metamorphism products of basalts, pillow lavas and diabasic dikes of Jandaq ophiolite. Amphibolites contain amphibole, plagioclase, garnet, alkali feldspar (orthoclase), magnetite, biotite, muscovite, sphene, quartz, epidote and calcite minerals. These rocks contain very good lineation and foliation. By metamorphic differentiation, mafic and felsic minerals are separated in some locations. Metasediments that are present in Jandaq area, were originaly sedimentary cover of Jandaq ophiolite, before the metamorphism has taken place. Mineralogical studies, hornblende barometry, and amphibole – plagioclase thermometry, conclude that the metamorphism of Jandaq ophiolite amphibolites occured in upper part of amphibolite facies condition (7.98 to 9.01 Kbars and 714 to 737 oC). Temperature of metamorphism in Jandaq ophiolite amphibolites is higher than amphibolites that are in Jandaq metamorphic rocks (8.58 to 10.87 Kbars and 619 to 668 oC).

Keywords


[1] Almasian M., "Tectonics of the Anarak area (Central Iran)", Islamic Azad University, Science and Research Unit, PhD thesis (1997) 164 p.

[2] Technoexport, "Geology of Anarak area (Central Iran)", Geological Survey of Iran, V/O “Technoexport”, Report TE/No. 19 (1984) 136 p.

[3] Technoexport, "Outline of metallogeny of Anarak area (Central Iran)", Geological Survey of Iran, V/O “Technoexport”, Report TE/No. 21 (1984) 132 p.

[4] Technoexport, "Geology and minerals of Jandaq area (Central Iran)", Geological Survey of Iran, V/O “Technoexport”, Report TE/No. 4 (1979) 171 p.

[5] Davoudzadeh M., Lensch G. and Diefenbach K.W., "Contribution to the paleogeography, stratigraphy and tectonics of the Infracambrian and lower Paleozoic of Iran", Neues Jahrbuch Fur geologie und palaontolgie Abhandlungen 172 (1986) 245 – 269.

[6] Davoudzadeh M., "Geology of Iran, In: E. M. Moores and R. W. Fairbridge (Eds.): Encyclopedia of Asian and European Regional Geology: 384-405", Chapman and Hall (1997) 903 p.

[7] هاتف محمد رضا، "زمین شناسی و پترولوژی سنگ های آذرین و دگرگونی منطقه خور – جندق (ایران مرکزی)"، پایان نامه کارشناسی ارشد پترولوژی، گروه زمین شناسی دانشگاه اصفهان (1374) 213 صفحه.

[8] Pessagno E.A. Jr., Ghazi A.M., Kariminia S.M., Duncan R.A., Hassanipak A.A., "Tectonostratigraphy of the Khoy complex, Northwestern Iran", Stratigraphy, 1, no. 2 (2004) 49-63.

[9] ترابی، قدرت، "پترولوژی افیولیت های منطقه انارک (شمال شرق استان اصفهان) با تاکید بر مطالعه سنگ های اولترامافیک-مافیک افیولیت شمال انارک و سنگ های اولترامافیک-مافیک ملانژ افیولیتی عشین-زوار"، رساله دکترای پترولوژی، بخش زمین شناسی دانشگاه تربیت مدرس (1383) 240 صفحه.

[10] Droop G.T.R., "A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria", Mineralogical Magazine 51 (1987) 431-435.

[11] Spear F.S., "Metamorphic Phase Equilibra and Pressure-Temperature-Time Paths", Mineralogical Society of America (1995) 799 p.

[12] Hammarstrom J.M., Zen E., "Aluminum in hornblende: An empirical igneous geobarometer", American Mineralogist 71 (1986) 1297-1313.

[13] Anderson J.L., "Status of thermobarometry in granitic batholiths", Transactions of the Royal Society of Edinburgh 87 (1996) 125-138. [also published in GSA Special Paper 315].

[14] Anderson J.L., Smith D.R., "The effect of temperature and oxygen fugacity on Al-in-hornblende barometry", American Mineralogist 80 (1995) 549-59.

[15] Hollister L.S., Grissom G.C., Pters E.K., Stowell H.H., Sisson V.B., "Confirmation of the empirical correlation of Al in hornblende with pressure of solidification of calc-alkaline plutons", American Mineralogist 72 (1987) 231-239.

[16] Johnson M.C., Rutherford M.J., "Experimental calibration of an aluminum-in-hornblende geobarometer with application to Long Valley caldera (California) volcanic rocks", Geology 17 (1989) 837-841.

[17] Schmidt M.W., "Amphibole composition in tonalite as a function of pressure: an experimental calibration of the Al-in-hornblende barometer", Contrib. Mineral. and Petrol. 110 (1992) 304-10.

[18] Schmidt M.W., "Phase relations and compositions in tonalite as a function of pressure: an experimental study at 650 °C", American Journal of Science 293 (1993) 1011-60.

[19] Blundy J.D. and Holland T.J.B., "Calcic amphibole equilibria and a new amphibole-plagioclase geothermometer", Contributions to Mineralogy and Petrology 104 (1990) 208-24.

[20] Holland T. and Blundy J., "Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry", Contributions to Mineralogy and Petrology 116 (1994) 433-47.

[21] Yardley B.W.D., "An introduction to metamorphic petrology", Longman, London, (1989) 248 p.