Document Type : Original Research Paper
Authors
1 Ph.D. Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran
2 Professor, Department of Geology, Faculty of Sciences, University of Birjand, Birjand, Iran
Abstract
The late Paleocene – early Eocene granitoid intrusions in the northern Sistan suture zone are regarded as potential tools to record tectonic events. A structural study of the Zahri granitoid body, based on the anisotropy of magnetic susceptibility (AMS) technique provides new data to characterize the internal structure and the kinematic reconstruction. The NW–SE trending body consists basically granite to leucogranite. Based on the results of the analysis of over 360 samples collected from 36 sites, the granitoid body is characterized by a low susceptibility and petrographic observations indicate that paramagnetic minerals such as biotite and amphibole are the most important iron-bearing mineral and can be considered as the main carrier of magnetic susceptibility. Magnetic foliations dominated by moderate dip and foliation strike mostly parallel to the elongated shape of the body, the magnetic lineation mainly trends NE-SW to N-S with plunges to the SW (mean orientation N 197°/32°) and formed during the emplacement and crystallisation of the magma. The Zahri body emplaced in an extensional setting controlled by a NNE-SSW opening direction associated with spaces of the sinistral shear zone in the terminations of Nehbandan fault system during the early Eocene.
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Archanjo, C., Hollanda, M. H., Rodrigues, S., Neves, B. and Armstrong, R., 2008- Fabrics of pre- and syntectonic granite plutons and chronology of shear zones in the Eastern Borborema Province, NE Brazil. Journal of Structural Geology, 30: 310- 326. [https://doi.org/10.1016/j.jsg.2007.11.011].
Be Mezeme, E., Faure, M., Chen, Y., Cocherie, A. and Talbot, J. Y., 2007- Structural, AMS and geochronological study of a laccolith emplaced during Late Variscan orogenic extension: the Rocles pluton (SE French Massif Central). International Journal of Earth Sciences, 96: 215- 228. [https://doi.org/10.1007/s00531-006-0098-2].
Benn, K., Ham, N. M. and Pignotta, G. S., 1998- Emplacement and deformation of granites during transpression: magnetic fabrics of the Archean Sparrow pluton, Slave Province, Canada. Journal of Structural Geology, 20: 1247- 1259. [https://doi.org/10.1016/S0191-8141(98)00065-0].
Benn, K., Paterson, S. R., Lund, S. P., Pignotta, G. S. and Kruse, S., 2001- Magmatic fabrics in batholiths as markers of regional strains and plate kinematics: example of the Cretaceous Mt. Stuart batholith. Physics and Chemistry of the Earth, 26: 343- 354. [https://doi.org/10.1016/S1464-1895(01)00064-3].
Berberian, M. and King, G. C., 1981- Towards a paleogeography and tectonic evolution of Iran. Canadian Journal of Earth Sciences, 18: 210- 265. [https://doi.org/10.1139/e81-019].
Borradaile, G. l. and Alford, C., 1988- Experimental shear zones and magnetic fabrics. Journal of Structural Geology, 10: 895- 904. [https://doi.org/10.1016/0191-8141(88)90102-2].
Bouchez, J. L., 1997- Granite is never isotropic: an introduction to AMS studies of granitic rocks, In: Bouchez, J.L., Hutton, D.H.W. and Stephens, W. E., (Eds), Granite: From Segregation of Melt to Emplacement Fabrics. Kluwer Academic Publishers, Dordrecht, pp. 95- 112. [https://doi.org/10.1007/978-94-017-1717-5_6].
Bouchez, J. L., Delas, C., Gleizes, G., Nedelec, A. and Cuney, M., 1992- Submagmatic microfractures in granites. Geology, 20: 35- 38. [https://doi.org/10.1130/0091-7613(1992)020%3C0035:SMIG%3E2.3.CO;2].
Brocker, M., Fotoohi Rad, G. R., Burgess, R., Theunissen, S., Paderin, I., Rodionov, N. and Salimi, Z., 2013- New age constraints for the geodynamic evolution of the Sistan Suture Zone, eastern Iran. Lithos, 170- 171: 17- 34. [https://doi.org/10.1016/j.lithos.2013.02.012].
Camp, V. E. and Griffis, R. J., 1982- Character, genesis and tectonic setting of igneous rocks in the Sistan suture zone, eastern Iran. Lithos, 15: 221- 239. [https://doi.org/10.1016/0024-4937(82)90014-7].
Esmaeily, D., Bouchez, J. L. and Siqueira, R., 2007- Magnetic fabrics and microstructures of the Shah Kuh Jurassic granite pluton (Lut block, Eastern Iran) and geodynamic inference. Tectonophysics, 439: 149- 170. [https://doi.org/10.1016/j.tecto.2007.04.002].
Gébelin, A., Brunel, M., Monié, P., Faure, M. and Arnaud, N., 2007- Transpressional tectonics and Carboniferous magmatism in the Limousin, Massif Central, France: Structural and 40 Ar/ 39 Ar investigations. Tectonics, 26: TC2008. [https://doi.org/10.1029/2005TC001822].
Ghalamghash, J., Nedelec, A., Bellon, H., Vosoughi Abedini, M. and Bouchez, J. L., 2009- The Urumieh plu tonic complex (NW Iran): A record of the geodynamic evolution of the Sanandaj-Sirjan zone during Cretaceous times—Part I: Petrogenesis and K/Ar dating. Journal of Asian Earth Sciences, 35: 401- 415. [https://doi.org/10.1016/j.jseaes.2009.02.002].
Guinebertedu, B., Bouchez, J. L. and Vigneresse, J. L., 1987- The Mortagne granite pluton (France) emplaced by pull apart along a shear zone: Structural and gravimetric arguments and regional implication. Geological Society of America Bulletin, 99: 866- 879. [https://doi.org/10.1130/0016-7606(1987)99%3C763:TMGPFE%3E2.0.CO;2].
Hobbs, B. E., Means, W. D. and Williams, P. F., 1976- An Outline of Structural Geology. John Wiley and Sons, pp. 278–280.
Hrouda, F. and Lanza, R., 1988- Magnetic fabric in the Biella and Traversella stocks (Periadriatic Line): implications for the mode of emplacement. Physics of the Earth and Planetary Interiors, 56: 337- 348. [https://doi.org/10.1016/0031-9201(89)90168-4].
Hrouda, F., Jelínek, V. and Hrusková, L., 1990- A package of programs for statistical evaluation of magnetic data using IBM-PC computers, EOS Trans Am Geophys Union, 71: 1289.
http://www.geosciences.ulg.ac.be/uploads/Documents/mapping/Bolle.pdf
Hutton, D. H. W., 1988- Granite emplacement mechanisms and tectonic controls: inferences from deformation studies, Transactions of the Royal Society of Edinburgh. Earth Sciences, 79: 245- 255. [https://doi.org/10.1017/S0263593300014255].
Jelinek, V., 1978- Statistical processing of anisotropy of magnetic susceptibility measured on groups of specimens. Studia Geophys. Geod, 22: 50- 62. [https://doi.org/10.1007/BF01613632].
Jelinek, V., 1981- Characterization of the magnetic fabric of rocks. Tectonophysics, 79: 563- 567. [https://doi.org/10.1016/0040-1951(81)90110-4].
Lyra, D. S., Savian, J. F., Bitencourt, M. D., Trindade, R. L. F. and Tomé, C. R., 2017- AMS fabrics and emplacement model of Butiá Granite, an Ediacaran syntectonic peraluminous granite from southernmost Brazil. Journal of South American Earth Sciences, In Press. [https://doi.org/10.1016/j.jsames.2017.12.006].
Mamtani, M. A. and Greiling, R. O., 2010- Serrated quartz grain boundaries, temperature and strain rate: testing fractal techniques in a syntectonic granite. In: Spalla, I., Marotta, A.M., Gosso, G. (Eds.), Advances in Interpretation of Geological Processes: Refinement of Multi-Scale Data and Integration in Numerical Modelling. Geological Society of London, Special Publications, 332: 35- 48.
Martin-Hernandez, F., Luneburg, C. M., Aubourg, C. and Jackson, M. (Eds), 2004- Magnetic Fabric: Methods and Applications. Geological Society, London, Special publications, 238. [https://doi.org/10.1144/GSL.SP.2004.238.01.01].
Martins, H. C. B., Sant’Ovaia, H., Abreu, J., Oliveira, M. and Noronha, F., 2011- Emplacement of the Lavadores granite (NW Portugal): U/Pb and AMS results. Comptes Rendus Geoscience, 343: 387- 396. [https://doi.org/10.1016/j.crte.2011.05.002].
Mondal, T. K., 2018- Evolution of fabric in Chitradurga granite (south India)- A study based on microstructure, anisotropy of magnetic susceptibility (AMS) and vorticity analysis. Tectonophysics, 723: 149- 161. [https://doi.org/10.1016/j.tecto.2017.12.013].
Montalbano, S., Diot, H. and Bolle, O., 2016- Asymmetrical magnetic fabrics in the Egersund doleritic dike swarm (SW Norway) reveal sinistral oblique rifting before the opening of the Iapetus. Journal of Structural Geology, 85: 18- 39. [https://doi.org/10.1016/j.jsg.2016.01.006].
Movahhed-Avval, H. and Emami, M. H., 1978- Geological map of MOKHTARAN 1:100,000. Geological Survey of Iran.
Navai, I., 1974- Geological map of SAHLABAD 1:100,000. Geological Survey of Iran.
Pang, K. N., Chung, S. L., Zarrinkoub, M. H., Khatib, M. M., Mohammadi, S. S., Chiu, H. Y., Chu, C. H., Lee, H. Y. and Lo, C. H., 2013- Eocene–Oligocene post-collisional magmatism in the Lut–Sistan region, eastern Iran: Magma genesis and tectonic implications. Lithos, 180-181: 234- 251. [https://doi.org/10.1016/j.lithos.2013.05.009].
Parés, J. M. and Van der Pluijm, B., 2002- Evaluating magnetic lineation (AMS) in deformedrocks. Tectonophysics, 350: 283- 298. [https://doi.org/10.1016/S0040-1951(02)00119-1].
Passchier, C. W. and Trouw, R. A. J., 2005- Microtectonics. Springer, Berlin. 315p.
Paterson, S. R. and Fowler, T. K., 1993- Re-examining pluton emplacement processes. Journal of Structural Geology, 15: 191- 206. [https://doi.org/10.1016/0191-8141(93)90095-R].
Paterson, S. R., Fowler, T. K., Schmidt, K. L., Yoshinobu, A. S., Yuan, E. S. and Miller, R. B., 1998- Interpreting magmatic fabric patterns in plutons. Lithos, 44:53- 82. [https://doi.org/10.1016/S0024-4937(98)00022-X].
Paterson, S. R., Vernon, R. H. and Tobish, O. T., 1989- A review of criteria for the identification of magmatic and tectonic foliations in granitoids. Journal of Structural Geology, 11: 349- 363. [https://doi.org/10.1016/0191-8141(89)90074-6].
Raposo, M. I. B., D'Agrella-Filho, M. S. and Pinese, J. P. P., 2007- Magnetic fabrics and rock magnetism of Archaean and Proterozoic dike swarms in the southern São Francisco Craton, Brazil. Tectonophysics, 443: 53- 71. [https://doi.org/10.1016/j.tecto.2007.08.001].
Rochette, P., 1987- Magnetic susceptibility of the rock matrix related to magnetic fabric studies. Journal of Structural Geology, 9:1015- 1020. [https://doi.org/10.1016/0191-8141(87)90009-5].
Sadeghian, M., Bouchez, J. L., Nedelec, A., Siqueira, R. and Valizadeh, M. V., 2005- The granite pluton of Zahedan (SE Iran): a petrological and magnetic fabric study of a syntectonic sill emplaced in a transtensional setting. Journal of Asian Earth Sciences, 25: 301- 327. [https://doi.org/10.1016/j.jseaes.2004.03.001].
Saint-Blanquat (de), M. and Tikoff, B., 1997- Development of magmatic to solid-state fabrics during syntectonic emplacement of the Mono Creek granite, Sierra Nevada batholith. In: Bouchez, J. L., Hutton, D. H. W. and Stephens, W.E., (Eds), Granites: From segregation of melt to emplacement Fabrics. Kluwer Academic Publishers, Dordrecht, pp. 231- 252. [https://doi.org/10.1007/978-94-017-1717-5_15].
Talbot, J. Y., Faure, M., Chen, Y. and Martelet, G., 2005- Pull-Apart emplacement of the Margeride granitic complex (French Massif Central). Implications for the late evolution of the Variscan orogeny. Journal of Structural Geology, 27:1610- 1629. [https://doi.org/10.1016/j.jsg.2005.05.008].
Tarling, D. H. and Hrouda, F., 1993- The magnetic anisotropy of rocks. Chapman and Hall, Bury St Edmunds, p. 217.
Theunissen, S., Brocker, M. and Fotoohi Rad, G. H., 2010- HP metamorphism in the Sistan suture zone, eastern Iran: New insights from Rb-Sr data. 88th Annual meeting of the German Mineralogical Society, Münster, Germany.
Tikoff, B. and Teyssier, C., 1992- Crustal-scale, en echelon ‘P-shear’ tensional bridges: A possible solution to the batholithic room problem. Geology, 20: 927- 930. [https://doi.org/10.1130/0091-7613(1992)020%3C0927:CSEEPS%3E2.3.CO;2].
Tirrul, R., Bell, I. R., Griffis, R. J. and Camp, V. E., 1983- The Sistan suture zone of eastern Iran. Geological Society of America Bulletin, 94: 134- 150. [https://doi.org/10.1130/0016-7606(1983)94%3C134:TSSZOE%3E2.0.CO;2].
Trubac, J., Zak, J., Chlupacova, M. and Janousek, V., 2009- Magnetic fabric of the Říčany granite, Bohemian Massif: a record of helical magma flow? Journal of Volcanology and Geothermal Research, 181: 25- 34. [https://doi.org/10.1016/j.jvolgeores.2008.12.005].
Vernant, P., Nilforoushan, F., Hatzfeld, D., Abbassi, M. R., Vigny, C., Masson, F., Nankali, H., Martinod, J., Ashtiani, A., Bayer, R., Tavakolim, F. and Chéry, J., 2004- Present-day crustal deformation and plate kinematics in the Middle East constrained by GPS measurements in Iran and northern Oman. Geophysical Journal International, 157: 381- 398. [https://doi.org/10.1111/j.1365-246X.2004.02222.x].
Vernon, R. H., Johnson, S. E. and Melis, E. A., 2004- Emplacement related microstructures in the margin of a deformed pluton: the San Jose tonalite, Baja California, Mexico. Journal of Structural Geology, 26: 1867- 1884. [https://doi.org/10.1016/j.jsg.2004.02.007].
Walker, R. and Jackson, J., 2002- Offset and evolution of the Gowk fault, SE Iran: a major intra-continental strike–slip system. Journal of Structural Geology, 24: 1677- 1698. [https://doi.org/10.1016/S0191-8141(01)00170-5].
Walker, R. and Jackson, J., 2004- Active tectonics and late Cenozoic strain distribution in central and eastern Iran. Tectonics, 23: TC5010. [https://doi.org/10.1029/2003TC001529].
Zarrinkoub, M. H., Chung, S. L., Chiu, H. Y., Mohammadi, S. S., Khatib, M. M. and Lin, I. J., 2010- Zircon U–Pb age and geochemical constraints from the northern Sistan suture zone on the Neotethyan magmatic and tectonic evolution in eastern Iran. Abstract to GSA Conference on “Tectonic Crossroads: Evolving Orogens in Eurasia–Africa–Arabia”, Turkey, 520p.
Zarrinkoub, M. H., Pang, K. N., Chung, S. L., Khatib, M. M., Mohammadi, S. S., Chiu, H. Y. and Lee, H. Y., 2012- Zircon U–Pb ages and geochemical constraints on the origin of the Birjand ophiolite, eastern Iran. Lithos, 154: 392–405. [https://doi.org/10.1016/j.lithos.2012.08.007].
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