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Zagros orogeny; a subduction-dominated process

Philippe Agard, J. Omrani, L. Jolivet, H. Whitechurch, B. Vrielynck, W. Spakman, P. Monie, B. Meyer and R. Wortel
Zagros orogeny; a subduction-dominated process (in The Zagros; geodynamics and overall structure, Mark B. Allen (prefacer))
Geological Magazine (November 2011) 148 (5-6): 692-725

Abstract

This paper presents a synthetic view of the geodynamic evolution of the Zagros orogen within the frame of the Arabia-Eurasia collision. The Zagros orogen and the Iranian plateau preserve a record of the long-standing convergence history between Eurasia and Arabia across the Neo-Tethys, from subduction/obduction processes to present-day collision (from approximately 150 to 0 Ma). We herein combine the results obtained on several geodynamic issues, namely the location of the oceanic suture zone, the age of oceanic closure and collision, the magmatic and geochemical evolution of the Eurasian upper plate during convergence (as testified by the successive Sanandaj-Sirjan, Kermanshah and Urumieh-Dokhtar magmatic arcs), the P-T-t history of the few Zagros blueschists, the convergence characteristics across the Neo-Tethys (kinematic velocities, tomographic constraints, subduction zones and obduction processes), together with a survey of recent results gathered by others. We provide lithospheric-scale reconstructions of the Zagros orogen from approximately 150 to 0 Ma across two SW-NE transects. The evolution of the Zagros orogen is also compared to those of the nearby Turkish and Himalayan orogens. In our geotectonic scenario for the Zagros convergence, we outline three main periods/regimes: (1) the Mid to Late Cretaceous (115-85 Ma) corresponds to a distinctive period of perturbation of subduction processes and interplate mechanical coupling marked by blueschist exhumation and upper-plate fragmentation, (2) the Paleocene-Eocene (60-40 Ma) witnesses slab break-off, major shifts in arc magmatism and distributed extension within the upper plate, and (3) from the Oligocene onwards ( approximately 30-0 Ma), collision develops with a progressive SW migration of deformation and topographic build-up (Sanandaj-Sirjan Zone: 20-15 Ma, High Zagros: approximately 12-8 Ma; Simply Folded Belt: 5-0 Ma) and with partial slab tear at depths ( approximately 10 Ma to present). Our reconstructions underline the key role played by subduction throughout the whole convergence history. We finally stress that such a long-lasting subduction system with changing boundary conditions also makes the Zagros orogen an ideal natural laboratory for subduction processes.


ISSN: 0016-7568
EISSN: 1469-5081
Coden: GEMGA4
Serial Title: Geological Magazine
Serial Volume: 148
Serial Issue: 5-6
Title: Zagros orogeny; a subduction-dominated process
Title: The Zagros; geodynamics and overall structure
Affiliation: Universite Pierre et Marie Curie, Institut des Sciences de la Terre de Paris, Paris, France
Affiliation: University of Durham, Department of Earth Sciences, United Kingdom
Pages: 692-725
Published: 201111
Text Language: English
Publisher: Cambridge University Press, London, United Kingdom
References: 230
Accession Number: 2011-103429
Categories: Solid-earth geophysicsStructural geology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch maps
N28°00'00" - N35°00'00", E49°00'00" - E54°00'00"
Secondary Affiliation: Geological Survey of Iran, IRN, IranUniversite d'Orleans, FRA, FranceEcole et Observatoire des Sciences de la Terre, FRA, FranceUtrecht University, NLD, NetherlandsUniversite de Montpellier II, FRA, France
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Cambridge University Press. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201152

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