Preprints
https://doi.org/10.5194/se-2021-71
https://doi.org/10.5194/se-2021-71

  27 May 2021

27 May 2021

Review status: a revised version of this preprint is currently under review for the journal SE.

Impact of Timanian thrust systems on the late Neoproterozoic–Phanerozoic tectonic evolution of the Barents Sea and Svalbard

Jean-Baptiste P. Koehl1,2,3,4, Craig Magee5, and Ingrid M. Anell6 Jean-Baptiste P. Koehl et al.
  • 1Centre for Earth Evolution and Dynamics (CEED), University of Oslo, PO Box 1028 Blindern, N-0315 Oslo, Norway
  • 2Department of Geosciences, UiT The Arctic University of Norway in Tromsø, N-9037 Tromsø, Norway
  • 3Research Centre for Arctic Petroleum Exploration (ARCEx), UiT The Arctic University of Norway in Tromsø, N-9037 Tromsø, Norway
  • 4CAGE – Centre for Arctic Gas Hydrate, Environment and Climate, UiT The Arctic University of Norway in Tromsø, N-9037 Tromsø, Norway
  • 5School of Earth Science and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom
  • 6Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, N-0316 Oslo, Norway

Abstract. The Svalbard Archipelago is composed of three basement terranes that record a complex Neoproterozoic–Phanerozoic tectonic history, including four contractional events (Grenvillian, Caledonian, Ellesmerian, and Eurekan) and two episodes of collapse- to rift-related extension (Devonian–Carboniferous and late Cenozoic). These three terranes are thought to have accreted during the early–mid Paleozoic Caledonian and Ellesmerian orogenies. Yet recent geochronological analyses show that the northwestern and southwestern terranes of Svalbard both record an episode of amphibolite (–eclogite) facies metamorphism in the latest Neoproterozoic, which may relate to the 650–550 Ma Timanian Orogeny identified in northwestern Russia, northern Norway and the Russian Barents Sea. However, discrete Timanian structures have yet to be identified in Svalbard and the Norwegian Barents Sea. Through analysis of seismic reflection, and regional gravimetric and magnetic data, this study demonstrates the presence of continuous, several kilometers thick, NNE-dipping, deeply buried thrust systems that extend thousands of kilometers from northwestern Russia to northeastern Norway, the northern Norwegian Barents Sea, and the Svalbard Archipelago. The consistency in orientation and geometry, and apparent linkage between these thrust systems and those recognized as part of the Timanian Orogeny in northwestern Russia and Novaya Zemlya suggests that the mapped structures are likely Timanian. If correct, these findings would indicate that Svalbard’s three basement terranes and the Barents Sea were accreted onto northern Norway during the Timanian Orogeny and should, hence, be attached to Baltica and northwestern Russia in future Neoproterozoic–early Paleozoic plate tectonics reconstructions. In the Phanerozoic, the study suggests that the interpreted Timanian thrust systems represented major preexisting zones of weakness that were reactivated, folded, and overprinted by (i.e., controlled the formation of new) brittle faults during later tectonic events. These faults are still active at present and can be linked to folding and offset of the seafloor.

Jean-Baptiste P. Koehl 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-2021-71', Anthony Doré, 18 Jun 2021
    • AC1: 'Reply on RC1', Jean-Baptiste Koehl, 21 Sep 2021
  • RC2: 'Comment on se-2021-71', Jeremy Rimando, 21 Jun 2021
    • AC2: 'Reply on RC2', Jean-Baptiste Koehl, 21 Sep 2021

Jean-Baptiste P. Koehl et al.

Jean-Baptiste P. Koehl et al.

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Short summary
The present study shows evidence of hundreds-thousands of kilometers long, several kilometers thick fault (large cracks in the Earth's crust) systems extending from northwestern Russia to the northern Norwegian Barents Sea and the Svalbard Archipelago using seismic, magnetic, and gravimetric data. The study suggests that the crust in Svalbard and the Barents Sea was already attached to Norway and Russia at ca. 650–550 Ma, thus challenging existing models.