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Geochemical evidence for deep mantle melting and lithospheric delamination as the origin of the inland Damavand volcanic rocks of northern Iran

Mirnejad, H. and Hassanzadeh, J. and Cousens, B. L. and Taylor, B. E. (2010) Geochemical evidence for deep mantle melting and lithospheric delamination as the origin of the inland Damavand volcanic rocks of northern Iran. Journal of Volcanology and Geothermal Research, 198 (3-4). pp. 288-296. ISSN 0377-0273. https://resolver.caltech.edu/CaltechAUTHORS:20110223-093925171

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Abstract

The intraplate Damavand volcanic field that overlies the Alborz Mountains in northern Iran is dominantly comprised of trachyandesite and alkali olivine basalt Alkali olivine basalt is the most primitive rock type among Damavand lavas and exhibits a number of geochemical characteristics (e.g., high MgO, Ni and Cr abundances) that preclude substantial differentiation and crustal contamination. The lavas are light rare earth element enriched and have small negative Nb-Ta-Ti and positive Ba and Pb anomalies. The initial Nd and Sr isotope compositions of these lavas plot within the mantle array and cluster near bulk silicate Earth-values, while Pb isotope ratios are typical of modern upper crust. Oxygen isotope ratios range from + 6.5 to + 6.9‰. Although previous studies suggest that the mantle source of the Damavand volcanic rocks was metasomatized by the release of fluids during Tertiary subduction of Neo-Tethys oceanic crust under the Iranian Plate, the geochemistry of the alkali olivine basalts (e.g., BSE-like Sr and Nd isotopic compositions; the position of samples on Ti/V vs. Zr/Nb, Ce/Pb vs. Ce, and Th-Ta-Hf diagrams) is not reconcilable with derivation of the parental magma from such a mantle source. In addition, the Mid-Ocean Ridge Basalt (MORB) normalized trace element patterns of the Damavand alkaline olivine basalts most resemble those of Ocean Island Basalt (OIB) that implies the role of deep mantle source in their genesis. It seems that local upwelling of deep mantle materials underneath the Alborz Mountains resulted in the eruption of intraplate Damavand lavas. Compressional stress exerted on the Iranian plate following Neo-Thetys closure was the likely cause of sub-continental lithosphere elamination which led to such local mantle upwelling.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.jvolgeores.2010.09.014 DOIUNSPECIFIED
http://www.sciencedirect.com/science/article/B6VCS-511TNBY-2/2/86a3acfaafe988e2ed95d57a58716906PublisherUNSPECIFIED
Additional Information:© 2010 Elsevier B.V. Received 16 February 2010. Accepted 9 September 2010. Available online 17 September 2010. We would like to thank the editor, Dr. M. J. Rutherford and anonymous reviewers for thorough reviews and comments. J. Davidson and J. Omrani are thanked for critically reading a revised version of the manuscript and providing constructive comments.
Subject Keywords:Damavand; delamination; Neo-Tethys; partial melting; deep mantle
Issue or Number:3-4
Record Number:CaltechAUTHORS:20110223-093925171
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20110223-093925171
Official Citation:H. Mirnejad, J. Hassanzadeh, B.L. Cousens, B.E. Taylor, Geochemical evidence for deep mantle melting and lithospheric delamination as the origin of the inland Damavand volcanic rocks of northern Iran, Journal of Volcanology and Geothermal Research, Volume 198, Issues 3-4, 15 December 2010, Pages 288-296, ISSN 0377-0273, DOI: 10.1016/j.jvolgeores.2010.09.014. (http://www.sciencedirect.com/science/article/B6VCS-511TNBY-2/2/86a3acfaafe988e2ed95d57a58716906)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22448
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:24 Feb 2011 16:04
Last Modified:03 Oct 2019 02:37

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