نبذة مختصرة : Structurally, the study area belongs to the tectonic range of the Central Alborz. The rocks were analyzed to detect main elements as well as rare and rare earth elements. Based on microscopic studies, the rocks in the region include basalt, trachyandesite and basaltic andesite with alkaline geochemical properties. According to geochemical studies, the early magma was affected by Nb, Ti, Ta, Eu negative anomalies, the enrichment of Rhizosphere rocks of rare earth elements (LRRE), high LREE/HREE ratio and low K/Nb ratio and high ratios of Th/Nb, La/Nb, Ba/Nb, Zr/ Nb magmatic contamination. The early basaltic magma has been formed of a garnet lherzolite mantle with phlogopite/pargasite by metasomatism at a pressure of 2.5-5.3 GPa at depths of more than 80-150 km. Structural evidence suggests the formation of these volcanic rocks in intercontinental rift zones. The formation of these rocks can be attributed to the effects of intercontinental extensional phases in deep faults during Eocene Alpine orogeny phases. ; Las actividades del magmatismo terciario en Alborz (Irán) se atribuyen principalmente a la subducción y final del neotetis. Este fenómeno es el objeto de este estudio, además de un acercamiento al origen del magma de esta área inferior. Adicionalmente, los autores estudiaron las características y origen del magma con base en la geoquímica de los elementos principales y de las tierras raras, y presentaron un modelo de su estado tectonomagmatico. El terciario volcánico de Alamut es parte del magmatismo en la secuencia central de rocas volcánicas en Alborz occidental (incluye basalto, traquiandesita, y andesita basáltica con propiedades geoquímicas alcalinas, con textura porfirítica, rocas piroclásticas y brecha volcánica), directamente sobre las unidades pertenecientes a la Formación Karaj (del Eoceno medio). Las propiedades geoquímicas indican que el magma madre se caracteriza por altos índices de elementos tierras raras ligeros y elementos tierras raras pesados, al igual que proporciones torio/niobio, ...
Relation: https://revistas.unal.edu.co/index.php/esrj/article/view/74025/80385; Abdel-Rahman, A. M., & Nassar, P. E. (2004). Cenozoic volcanism in the Middle East: petrogenesis of alkali basalts from northern Lebanon. Geological Magazine, 141, 545-563. https://doi.org/10.1017/S0016756804009604 Allen, M. B., Ghassemi, M. R., Shahrabi, M., & Qorashi, M. (2003). Accommodation of Late Cenozoic oblique shortening in the Alborz range, northern Iran. Journal of Structural Geology, 25, 659–672. https://doi.org/10.1016/S0191-8141(02)00064-0 Arfania, R. (2018). Role of supra-subduction zone ophiolites in the tectonic evolution of the southeastern Zagros Orogenic Belt, Iran. Iranian Journal of Earth Sciences, 10(1), 31-38. Berberian, M. (1982). The southern Caspian: A compressional depression floored by a trapped, modified oceanic crust. Canadian Journal of Earth Sciences, 20, 163-183. DOI:10.1139/e83-015 DePaolo, D. J., & Wasserberg, G. J. (1979). Neodymium isotopes in flood basalts from the Siberian Platform and inferences about their mantle sources. Proceedings of the National Academy of Science of the United States of America, 76, 3056-3060. https://doi.org/10.1073/pnas.76.7.3056 Derakhshi, M., Ghasemi, H., & Sahami, T. (2014). Geology and Petrology of the Soltan Maydan Basaltic Complex in North- Northeast of Shahrud Eastern Alborz, north of Iran. Scientific Quarterly Journal Geosciences, 23( 91). Ebrahimi, M., Esmaeili, R., & Aouizerat, A. (2017). New geodynamical model for the regional Tertiary extension during the Zagros orogeny: A transtensional arc? Iranian Journal of Earth Sciences, 9(2), 115-120. Haghnazar, S., Malakotian, S., & Allahyari, K. (2015). Tectono-magmatic setting of Cretaceous pillow basalts in the north part of the Alborz mountains in east of Guilan province (north of Iran): a part of ophiolite sequence or intra-continental rift? Iranian Journal of Geosciences, 24(94), 171-182. Haghnazar, S., Vosoughy Abebini, M., & Pourmoafi, M. (2009). Mantle source characteristics of Javaherdasht basalts (east of Gilan), Based on Attention to geochemical and isotopic features. Iranian Journal of Geology, 2(8), 95-102. Irvin, T., & Baragar, W. R. A. (1971). A guide to the chemical classification of the common volcanic rocks. Canadian Journal of Earth Science Letters, 8, 523-548. https://doi.org/10.1139/e71-055 Jafarian, A. S. R., Imami, M. E., & Vosoughi Abedini, M. (2009). Petrology and Geochemistry of the Main Elements of the Basalt Collection of Sultan Sq. Applied Geology Quarterly, 4, 1-19. Jung, S. (1999). The role of crustal contamination during the evolution of continental rift-related basalts. A case study from the Vogelsberg area (central Germany). Geolines, 9, 48-58 Le Bas, M. J., Le Maitre, R. W., Streckeisen, A., & Zanettin, B. (1986). A chemical classification of volcanic rocks based on the total alkali-silica diagram. Journal of Petrology, 27, 745-750. https://doi.org/10.1093/petrology/27.3.745 Le Roex, A. P., Dick, H. J. B., Erlank, A. J., Reid, A. M., Frey, F. A., & Hart, S. R. (1983). Geochemistry, mineralogy and petrogenesis of lavas erupted along the southwest Indian ridge between the Bouvet triple junction and 11 degrees east. Journal of Petrology, 24, 267-318. https://doi.org/10.1093/petrology/24.3.267 Meng, L., Li, Zh., Chen, H., Li, X., & Wang, X. (2012). Geochronological and geochemical results from Mesozoic basalts in southern South China Block support the flat-slab subduction model. Lithos, 127-140. https://doi.org/10.1016/j.lithos.2011.11.022 Plank, T., & Langmuir, C. H. (1988). An evaluation of the global variations in the major element chemistry of arc basalts. Earth Planet, 90, 349–370. https://doi.org/10.1016/0012-821X(88)90135-5 Ritz, J. F., Nazari, H., Ghasemi, A., & Salamati, R. (2006). Active transtension inside central Alborz: A new insight into northern Iran–southern Caspian geodynamics. Geology, 34, 477–480. https://doi.org/10.1130/G22319.1 Saunders, A. D., & Tarney, J. (1984). Geochemical characteristics of basaltic volcanism within back-arc basins In Marginal Basin Geology. Special Publication of the Geological Society, London, 16, 59-76. https://doi.org/10.1144/GSL.SP.1984.016.01.05 Shervais, J. W. (1982). Ti-V plots and the petrogenesis of modern and ophiolitic lavas. Earth and Planetary Science Letters, 59, 101–118. https://doi.org/10.1016/0012-821X(82)90120-0 Talusani, V. R. ( 2010). Bimodal tholeiitic and mildly alkalic basalts from Bhir area, central Deccan Volcanic Province, India: Geochemistry and petrogenesis. Journal of Volcanology and Geothermal Research, 189, 278-290. https://doi.org/10.1016/j.jvolgeores.2009.11.019 Verdel, C., Wernicke, B. P., & Hassanzadeh, J. (2011). A Paleogene extensional arc flare-up in Iran. Tectonics, 30, TC3008. https://doi.org/10.1029/2010TC002809 Wang, Y. N., Zhang, C. J., & Xiu, S. Z. (2001). Th/Hf-Ta/Hf identification of tectonic setting of basalts (in Chinese). Acta Petrologica Sinica, 17(3), 413-421. Xu, Y. G., Ma, J. L., Frey, F. A., Feigenson, M. D., & Liu, J. F. (2005). Role of lithosphere–asthenosphere interaction in the genesis of Quaternary alkali and tholeiitic basalts from Datong, western North China Craton. Chemical Geology, 224, 247-271. https://doi.org/10.1016/j.chemgeo.2005.08.004 Yaxley, G. M. (2000). Experimental study of the phase and melting relations of homogeneous basalt + peridotite mixtures and implications for the petrogenesis of flood basalts. Contributions to Mineralogy and Petrology, 139, 326-338. https://doi.org/10.1007/s004100000134 Zaeimnia, F., Kananian, A., & Salavaty, M. (2011). Petrogenesis of Southern Amlash Alkaline Rocks in the South Caspian Sea, North of Iran. Geosciences, 78, 69-78. Zanchi, A., Berra, F., Mattei, M., Zanchetta, S., Nawab, A., & Sabouri, J. (2005). The early Mesozoic Cimmerian orogeny in the Alborz mountains, Iran. Geophysical Research, 7, 1607-7962.; https://revistas.unal.edu.co/index.php/esrj/article/view/74025
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