Pre-collisional extension of microcontinental terranes by a subduction pulley

Erkan Gün*, Russell N. Pysklywec, Oğuz H. Göğüş, Gültekin Topuz

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Terrane accretion is a ubiquitous process of plate tectonics that delivers fragments of subduction-resistant lithosphere into a subduction zone, resulting in events such as ocean plateau docking or continental assembly and orogenesis. The post-collisional extension of continental terranes is a well-documented tectonic process linked with gravitational collapse and/or trench retreat. Here we propose that microcontinental terranes can also undergo a substantial extension before their collision with the upper plate, owing to pull from the trenchward part of the subducting plate. Forward geodynamic numerical experiments demonstrate that this pre-collisional extension can occur over a protracted phase on microcontinents that are drifting towards a subduction zone, which distinguishes the deformation from post-collisional extension on the overriding plate, as is traditionally postulated. The results show that the magnitude of pre-collisional extension is inversely correlated with the size of the microcontinental terrane and imposed convergence velocity. We find that locations along the Tethyan belts, namely, the Sesia zone and Eastern Anatolia, are evidence for this style of pre-collisional extension, as this mechanism reconciles with geothermobarometric data and kinematic analyses. The operation of this subduction pulley reveals that drifting lithospheric plates may undergo substantial tectonic events before the arrival and involvement with regular plate boundary processes.

Original languageEnglish
Pages (from-to)443-450
Number of pages8
JournalNature Geoscience
Issue number6
Publication statusPublished - Jun 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Limited.


This research was enabled in part by support provided by SciNet and Compute Canada ( A modified version of the SOPALE (2000) software was used to run numerical models. The SOPALE modelling code was originally developed by P. Fullsack at Dalhousie University with C. Beaumont and his Geodynamics group. We used Ö. F. Bodur’s script to plot the P–T–t paths. Funding for this research was provided by an NSERC Discovery Grant (RGPIN-2019-06803)-RNP and TÜBİTAK grant (114Y226) to G.T.

FundersFunder number
Compute Canada
Natural Sciences and Engineering Research Council of CanadaRGPIN-2019-06803
Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada


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