Teknik, Vahid, Thybo, Hans, Artemieva, Irina M. and Ghods, Abdolreza (2020) A new tectonic map of the Iranian plateau based on aeromagnetic identification of magmatic arcs and ophiolite belts. Tectonophysics, 792 (Article number 228588). DOI 10.1016/j.tecto.2020.228588.

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Abstract

Highlights

• The Radially averaged power spectrum method is applied to calculate average magnetic susceptibility in Iran.
• The results demonstrate that known occurrences of Magmatic-Ophiolite Arcs (MOA) correlate with high average susceptibility areas.
• We interpret two parallel, hitherto unknown, MOAs in eastern Iran which developed in a steeply dipping (>60° dip) subduction zone.
• Neo-Tethys subduction angle was shallow (<20° dip) of in NW Iran and steep (>60° dip) in SE Iran which indicates slab tearing.
• We define a new outline of the economically important Tabas sedimentary basin.

Abstract

The Iranian plateau is one of the most complex geodynamic settings within the Alpine-Himalayan belt. The Paleo-Tethys and Neo-Tethys ocean subduction is responsible for the formation of several magmatic arcs and sedimentary basins within the plateau. These zones mostly are separated by thrust faults related to paleo-suture zones, which are highlighted by ophiolites. Sediment cover and overprint of a different magmatic phase from late Triassic to the Quaternary impede identification of some magmatic arcs and ophiolite belts.

We track the known magmatic arcs, such as the Urmia-Dokhtar Magmatic Arc (UDMA), and unknown, sediment covered magmatic arcs by aeromagnetic data. We present a new map of average susceptibility calculated by the radially averaged power spectrum method. High average susceptibility values indicate the presence of a number of lineaments that correlate with known occurrences of Magmatic-Ophiolite Arcs (MOA), and low average susceptibility coincides with known sedimentary basins like Zagros, Makran, Kopeh-Dagh, and Tabas. In analogy to Zagros, low average susceptibility values indicate sedimentary basins to the south of the Darouneh fault and in the northern part of the Lut, Tabas and Yazd blocks. We interpret the Tabas basin as a pull-apart or back-arc basin. We identify hitherto unknown parallel MOAs in eastern Iran and the SE part of UDMA which both indicate steeply dipping (>60° dip) paleo-subduction zones. In contrast, we interpret shallow subduction (<20° dip) of Neo-Tethys in the NW part of UDMA as well as in the Sabzevar-Kavir MOA.

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