Breaking supercontinents; no need to choose between passive or active

Other literature type, Article English OPEN
Wolstencroft, Martin ; Davies, John Huw (2017)
  • Publisher: Copernicus Publications on behalf of the European Geosciences Union
  • Journal: (issn: 1869-9529, eissn: 1869-9529)
  • Related identifiers: doi: 10.5194/se-2017-14, doi: 10.5194/se-8-817-2017
  • Subject: Petrology | Q | QE500-639.5 | Dynamic and structural geology | QE640-699 | Science | QE1-996.5 | Geology | Stratigraphy | QE420-499

Much debate has centred on whether continental break-up is predominantly caused by active upwelling in the mantle (e.g. plumes) or by long-range extensional stresses in the lithosphere. We propose the hypothesis that global supercontinent break-up events should always involve both. The fundamental principle involved is the conservation of mass within the spherical shell of the mantle, which requires a return flow for any major upwelling beneath a supercontinent. This shallow horizontal return flow away from the locus of upwelling produces extensional stress. We demonstrate this principle with numerical models, which simultaneously exhibit both upwellings and significant lateral flow in the upper mantle. For non-global break-up the impact of the finite geometry of the mantle will be less pronounced, weakening this process. This observation should motivate future studies of continental break-up to explicitly consider the global perspective, even when observations or models are of regional extent.
  • References (77)
    77 references, page 1 of 8

    Allen, P. A. and Allen, J. R.: Basin Analysis, Principles and Applications, 2nd edn., Blackwell Publishing, Oxford, UK, ISBN: 0632052074, 549 pp., 2005.

    Allken, V., Huismans, R. S., and Thieulot, C.: Threedimensional numerical modeling of upper crustal extensional systems, J. Geophys. Res., 116, B10409, https://doi.org/10.1029/2011JB008319. 2011.

    Audet, P. and Bürgmann, R.: Dominant role of tectonics inheritance in supercontinent cycles, Nat. Geosci., 4, 184-187, 2011.

    Baumgardner, J. R.: Three dimensional treatment of convective flow in the Earth's mantle, J. Stat. Phys., 39, 501-511, 1985.

    Becker, T. W. and Faccenna, C.: Mantle conveyor beneath the Tethyan collisional belt, Earth Planet. Sc. Lett., 3103, 453-461, 2011.

    Bercovici, D. and Long, M. D.: Slab rollback instability and supercontinent dispersal, Geophys. Res. Lett., 41, 6659-6666, 2014.

    Bercovici, D. and Ricard, Y.: Plate tectonics, damage and inheritance, Nature, 508, 513-516, 2014.

    Bialas, R., Buck, W. R., and Qin, R.: How much magma is required to rift a continent?, Earth Planet. Sc. Lett., 292, 68-78, 2010.

    Bleeker, W.: The late Archean record: a puzzle in ca. 35 pieces, Lithos, 71, 99-134, 2003.

    Bott, M. H. P.: The stress regime associated with continental breakup, in: “Magmatism and the Causes of Continental Break-up”, edited by: Storey, B. C., Alabaster, T., and Pankhurst, R., J., Geol. Soc. Lond. Spec. Pub. 68, 125-136, 1992.

  • Metrics
    No metrics available
Share - Bookmark