Preprints
https://doi.org/10.5194/se-2021-68
https://doi.org/10.5194/se-2021-68

  19 May 2021

19 May 2021

Review status: a revised version of this preprint was accepted for the journal SE.

Detrital zircon provenance record of the Zagros mountain building from the Neotethys obduction to the Arabia-Eurasia collision, NW Zagros fold-thrust belt, Kurdistan region of Iraq

Renas I. Koshnaw1,a, Fritz Schlunegger1, and Daniel F. Stockli2 Renas I. Koshnaw et al.
  • 1Institute of Geology, University of Bern, Baltzerstrasse 1+3, CH- 3012 Bern, Switzerland
  • 2Department of Geological Sciences, Jackson School of Geosciences, University of Texas at Austin, Austin, TX 78712, USA
  • apresent address: Department of Structural Geology and Geodynamics, Geoscience Center, University of Göttingen, Goldschmidtstraße 3, 37077 Göttingen, Germany

Abstract. Recognition of new angular unconformity and synthesizing of new detrital zircon U-Pb and (U-Th)/He provenance records, including zircon (U-Th)/(He-Pb) double dating, from the NW Zagros elucidate the basin dynamics of the foreland wedge-top and intermontane units, as well as the tectonic processes in the source terranes in response to different geodynamic phases. In this contribution, we present field observations and detrital zircon provenance data from hinterland basins to reconstruct the basin dynamics and the underlying tectonic controls in the NW Zagros in the Kurdistan region of Iraq. Results reveal that the deposition of the suture zone units of the Red Beds Series (RBS; Suwais Group, Govanda Formation, Merga Group) occurred in an intermontane basin on top of folded Upper Cretaceous units with an angular unconformity. The RBS provenance data point at the Paleogene Walash-Naopurdan-Kamyaran (WNK) arc-related complex as a source area and show substantial decrease of magmatism by ~ 36 Ma, as reflected by the youngest ages peaks. New detrital zircon provenance data from the hinterland wedge-top units of the proto-Zagros foreland basin (the Tanjero, Kolosh, and Gercus Formations) exhibit exclusive derivation from the Upper Cretaceous Neotethys ophiolitic terranes, different from the provenance of the older Lower Cretaceous and Paleozoic units that are dominated by the Paleozoic and Neoproterozoic age spectra. These shifts in provenance between different tectonostratigraphic units argue for sediment route reversal from E to W in response to ophiolite obduction, arrival of the WNK complex and commencement of the continental collision during the late Eocene, followed by deposition of the RBS in the hinterland of the proto-Zagros fold-thrust belt, and paleodrainage connection with the post-collisional Neogene foreland basin.

Renas I. Koshnaw et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on se-2021-68', Frédéric Mouthereau, 15 Jun 2021
    • AC1: 'Reply on RC1: Mouthereau, Frédéric', Renas Koshnaw, 27 Aug 2021
  • RC2: 'Comment on se-2021-68', Anonymous Referee #2, 02 Aug 2021
    • AC2: 'Reply on RC2: Anonymous Referee', Renas Koshnaw, 27 Aug 2021

Renas I. Koshnaw et al.

Renas I. Koshnaw et al.

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Short summary
As continental plates collide, mountain belts grow. This study investigated the provenance of rocks from the northwestern segment of the Zagros mountain belt to unravel the convergence history of the Arabian and Eurasian plates. Provenance data synthesis and field relationships suggest that Zagros mountains developed as a result of the oceanic crust emplacement on the Arabian continental plate, followed by the Arabia-Eurasia collision, and later uplift of the broader region.