Spatio-temporal evolution of strain accumulation derived from multi-scale observations of Late Jurassic rifting in the northern North Sea : a critical test of models for lithospheric extension
Cowie, Patience A.
Underhill, John R.
Behn, Mark D.
Gill, Caroline E.
MetadataShow full item record
KeywordLithospheric extension; Strain accumulation; Normal faulting; Numerical modeling; Basin formation
We integrate observations of lithospheric extension over a wide range of spatial and temporal scales within the northern North Sea basin and critically review the extent to which existing theories of lithospheric deformation can account for these observations. Data obtained through a prolonged period of hydrocarbon exploration and production has yielded a dense and diverse data set over the entire Viking Graben and its flanking platform areas. These data show how syn-rift accommodation within the basin varied in space and time with sub-kilometer-scale spatial resolution and a temporal resolution of 2–3 Myr. Regional interpretations of 2D seismic reflection, refraction and gravity data for this area have also been published and provide an image of total basin wide stretching for the entire crust. These image data are combined with published strain rate inversion results obtained from tectonic subsidence patterns to constrain the spatio-temporal evolution of strain accumulation throughout the lithosphere during the 40 Myr (170–130 Ma) period of Late Jurassic extension across this basin. For the first 25–30 Myr, strain localisation dominated basin development with strain rates at the eventual rift axis increasing while strain rates over the flanking areas declined. As strain rates across the whole basin were consistently very low (< 3 × 10- 16 s- l), thermally induced strength loss cannot explain this phenomenon. The strain localisation is manifest in the near-surface by a systematic migration of fault activity. The pattern and timing of this migration are inconsistent with flexural bending stresses exerting an underlying control, especially when estimates of flexural rigidity for this area are considered. The best explanation for what is observed in this time period is a coupling between near-surface strain localisation, driven by brittle (or plastic) failure, and the evolving thermal structure of the lithosphere. We demonstrate this process using a continuum mechanics model for normal fault growth that incorporates the strain rate-dependence of frictional strength observed in laboratory studies. During the final 10 Myr of basin formation, strain accumulation was focused within the axis and strain rates declined rapidly. Replacement of weak crust by stronger mantle material plus crustal buoyancy forces can adequately explain this decline.
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 234 (2005): 401-419, doi:10.1016/j.epsl.2005.01.039.
Suggested CitationPreprint: Cowie, Patience A., Underhill, John R., Behn, Mark D., Lin, Jian, Gill, Caroline E., "Spatio-temporal evolution of strain accumulation derived from multi-scale observations of Late Jurassic rifting in the northern North Sea : a critical test of models for lithospheric extension", 2005-01-23, https://doi.org/10.1016/j.epsl.2005.01.039, https://hdl.handle.net/1912/362
Showing items related by title, author, creator and subject.
Airborne-radar and ice-core observations of annual snow accumulation over Thwaites Glacier, West Antarctica confirm the spatiotemporal variability of global and regional atmospheric models Medley, Brooke; Joughin, Ian; Das, Sarah B.; Steig, Eric J.; Conway, Howard; Gogineni, S.; Criscitiello, Alison S.; McConnell, Joseph R.; Smith, B. E.; van den Broeke, Michiel R.; Lenaerts, Jan T. M.; Bromwich, D. H.; Nicolas, J. P. (John Wiley & Sons, 2013-07-26)We use an airborne-radar method, verified with ice-core accumulation records, to determine the spatiotemporal variations of snow accumulation over Thwaites Glacier, West Antarctica between 1980 and 2009. We also present a ...
Observed and modeled Greenland ice sheet snow accumulation, 1958-2003, and links with regional climate forcing Hanna, Edward; McConnell, Joseph R.; Das, Sarah B.; Cappelen, John; Stephens, Ag (American Meteorological Society, 2006-02-01)Annual and monthly snow accumulation for the Greenland Ice Sheet was derived from ECMWF forecasts [mainly 40-yr ECMWR Re-Analysis (ERA-40)] and further meteorological modeling. Modeled accumulation was validated using 58 ...
Constraints on lithosphere net rotation and asthenospheric viscosity from global mantle flow models and seismic anisotropy Conrad, Clinton P.; Behn, Mark D. (American Geophysical Union, 2010-05-13)Although an average westward rotation of the Earth's lithosphere is indicated by global analyses of surface features tied to the deep mantle (e.g., hot spot tracks), the rate of lithospheric drift is uncertain despite its ...