Lithospheric structure beneath NW Iran using regional and teleseismic travel-time tomography

Bavali, K. and Motaghi, K. and Sobouti, F. and Ghods, A. and Abbasi, M. and Priestley, K. and Mortezanejad, G. and Rezaeian, M. (2016) Lithospheric structure beneath NW Iran using regional and teleseismic travel-time tomography. Physics of the Earth and Planetary Interiors, 253. pp. 97-107. ISSN 0031-9201 DOI 10.1016/j.pepi.2016.02.006

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Official URL: http://doi.org/10.1016/j.pepi.2016.02.006

Abstract

We compute a 2-D tomogram using the P wave arrival time readings from a temporary seismic experiment to study the seismic structure of the crust and upper mantle in NW Iran. The study area includes the western margins of the South Caspian Basin (SCB), and the Sahand and Sabalan post-collisional volcanoes in NW Iran. We invert 2780 regional and teleseismic relative P wave arrival times recorded by 23 stations along the seismic profile extending from the western shoreline of the Caspian Sea to Lake Urumieh. Our tomographic results show a higher-velocity region beneath the SCB. The observed higher velocities strongly correlate with the observed positive gravity anomalies over the southwestern margins of the Caspian Sea, suggesting an oceanic like nature for the SCB lithosphere. The tomographic results also show several lower-velocity anomalies in the crust. The Sabalan volcano is underlain by a low-velocity zone in the lower crust, which is most likely thermal in nature. In the Sahand region, the lower velocities are considerably shallower in depth and might be controlled by shallow sedimentary structures, as well as an anomalously warm upper crust. The shallow low-velocity regions are connected with deeper low-velocity zones 60–100 km deep in the upper mantle. This pattern points to a possible mantle source of post-collisional volcanism in NW Iran, i.e. the melting of a subducted slab.

Item Type: Article
Uncontrolled Keywords: 2015AREP, IA70
Subjects: 02 - Geodynamics, Geophysics and Tectonics
Divisions: 02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title: Physics of the Earth and Planetary Interiors
Volume: 253
Page Range: pp. 97-107
Identification Number: 10.1016/j.pepi.2016.02.006
Depositing User: Sarah Humbert
Date Deposited: 28 Apr 2016 13:52
Last Modified: 28 Apr 2016 13:52
URI: http://eprints.esc.cam.ac.uk/id/eprint/3653

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