Rifted margins result from rifting and continental breakup, and often contain remnants of their rifting history in their complex structural architecture. Seismic studies reveal that magma-poor and magma-rich margins are not just a simple juxtaposition of oceanic and continental crust, but that the transition between the oceanic and continental domains may include various crustal bodies such as microcontinents and continental fragments. Microcontinents present a perplexing formation scenario: seafloor spreading ends in a region that is already warm, and thus weak, and is initiated elsewhere in a region of stronger lithosphere. In this project, we investigated various scenarios for microcontinent formation using dynamic numerical models. The project was financed by Det Norske.
Participants: Joya Tetreault (NGU) and Susanne Buiter (NGU).
- Tetreault, J.L. and S.J.H. Buiter, 2018, The influence of extension rate and crustal rheology on the evolution of passive margins from rifting to break-up, Tectonophysics 746, 155-172, doi: 10.1016/j.tecto.2017.08.029
- Tetreault, J. and S. Buiter, 2015a, Scenarios of microcontinent formation applied to the Jan Mayen microcontinent, NGU report 2015.019
- Tetreault, J. and S. Buiter, 2015b, Crustal structure of continental fragments, NGU report 2015.018
Numerical and laboratory models are often used to investigate the evolution of deformation processes in the crust and lithosphere. In both approaches, the freedom in choice of simulation method, materials and their properties, and deformation laws could affect model outcomes. To assess the role of modelling method and to quantify the variability among models, we have performed a comparison of results of 11 numerical codes and 15 laboratories for the same setups. We chose three experiments that describe shortening of a sand-like, brittle wedge.
- Buiter, S.J.H., G. Schreurs, M. Albertz, T.V. Gerya, B. Kaus, W. Landry, L. Le Pourhiet, Y. Mishin, D.L. Egholm, M. Cooke, B. Maillot, C. Thieulot, T. Crook, D. May, P. Souloumiac, and C. Beaumont, 2016, Benchmarking numerical models of brittle thrust wedges, Journal of Structural Geology 92, 140-177, doi: 10.1016/j.jsg.2016.03.003
- Schreurs, G., S.J.H. Buiter, J. Boutelier, C. Burberry, J.-P. Callot, C. Cavozzi, M. Cerca, J.-H. Chen, E. Cristallini, A.R. Cruden, L. Cruz, J.-M. Daniel, G. Da Poian, V.H. Garcia, C.J.S. Gomes, C. Grall, Y. Guillot, C. Guzmán, T. Nur Hidayah, G. Hilley, M. Klinkmüller, H.A. Koyi, C.-Yu Lu, B. Maillot, C. Meriaux, F.Nilfouroushan, C.-C. Pan, D. Pillot, R. Portillo, M. Rosenau, W.P. Schellart, R.W. Schlische, A. Take, B. Vendeville, M. Vergnaud, M. Vettori, S.-H. Wang, M.O. Withjack, D. Yagupsky, and Y. Yamada, 2016, Benchmarking analogue models of brittle thrust wedges, Journal of Structural Geology 92, 116-139, doi: 10.1016/j.jsg.2016.03.005
The Wilson Cycle describes the closing and opening of an ocean along the same plate boundary (J.T. Wilson, 1966, Did the Atlantic close and then re-open? Nature 211, 676-681). For example, the Iapetus Ocean between the Norwegian margin of Baltica and the Greenland margin of Laurentia closed by subduction and collision around 425 million years ago. This led to the formation of the Caledonide mountains and the high-pressure rocks now exposed in western Norway. Extension caused break-up of the new continent and the formation of the North Atlantic Ocean from around 54 million years ago. In this project, we investigated the dynamics of the different stages of a Wilson Cycle: closure of an ocean by subduction, the end of convergence by continental collision, and subsequent rifting. The project was financed by the Norwegian Research Council (project 180449/V30) and the Geological Survey of Norway.
Participants: Susanne Buiter (NGU, now at RWTH Aachen University), Joya Tetreault (NGU), Reza Khabbaz Ghazian (NGU, now at Equinor), Susan Ellis (GNS Science), Torgeir Andersen (University of Oslo, now retired), Trond Torsvik (University of Oslo, NGU), and Per Terje Osmundsen (NGU, now at NTNU).
- Tetreault, J.L. and S.J.H. Buiter, 2014, Future accreted terranes: a compilation of island arcs, oceanic plateaus, submarine ridges, seamounts, and continental fragment, Solid Earth 5, 1243-1275, doi: 10.5194/se-5-1243-2014, online open access
- Buiter, S., 2014, How plumes help to break plates, Nature (News & Views), 513, 36-37.
- Ghazian, R.K. and S.J.H. Buiter, 2014, Numerical modelling of the role of salt in continental collision: An application to the southeast Zagros fold-and-thrust belt, Tectonophysics 632, 96-110, doi: 10.1016/j.tecto.2014.06.006
- Buiter, S.J.H. and T.H. Torsvik, 2014, A review of Wilson Cycle plate margins: A role for mantle plumes in continental break-up along sutures? Gondwana Research 26, 627-653, doi: 10.1016/j.gr.2014.02.007
- Buiter, S.J.H., F. Funiciello, and J. van Hunen (eds), 2013, Subduction Zones, Special issue in Solid Earth, oline open access
- Ghazian, R.K. and Buiter, S.J.H., 2013, A numerical investigation of continental collision styles, Geophysical Journal International 193, 1133-1152, doi: 10.1093/gji/ggt068
- Tetreault, J.L. and S.J.H. Buiter, 2012, Geodynamic models of terrane accretion: Testing the fate of island arcs, oceanic plateaus, and continental fragments in subduction zones, Journal of Geophysical Research 117, B08403, doi: 10.1029/2012JB009316
- Buiter, S.J.H., 2012, A review of brittle compressional wedge models, Tectonophysics 530-531, 1-17, doi: 10.1016/j.tecto.2011.12.018
- Crameri, F., Schmeling, H., Golabek, G.J., Duretz, T., Orendt, R., Buiter, S.J.H., May, D.A., Kaus, B.J.P., Gerya, T.V., Tackley, P.J., 2012, A comparison of numerical surface topography calculations in geodynamic modelling: An evaluation of the 'sticky air' method, Geophysical Journal International 189, 38-54, doi: 10.1111/j.1365-246X.2012.05388.x
- Ellis, S.M., Little, T.A., Wallace, L.M., Hacker, B.R., Buiter, S.J.H., 2011, Feedback between rifting and diapirism can exhume ultrahigh-pressure rocks, Earth and Planetary Science Letters 311, 427-438, doi: doi:10.1016/j.epsl.2011.09.031
The Congo Basin in Central Africa is characterised by a near-circular shape, pronounced negative free-air gravity anomaly, and long subsidence history. The basin probably initiated by late Precambrian rifting of thick cratonic lithosphere and a large part of its subsidence history could be explained by post-rift thermal relaxation. However, the upper 1 km of Mesozoic to Cenozoic sediments seems discontinuous in its evolution and several studies have proposed that these sediments were deposited in response to mantle processes. We examined gravity data and 18 seismic tomography models to evaluate the role of the sub-crustal mantle in the more recent evolution of the Congo Basin. Current seismic tomography and gravity data do not prove or disprove the various hypotheses put forward to explain the deposition of the Mesozoic-Cenozoic sedimentary rocks, but the large variability between the tomographic models indicates that it is unlikely that the mantle would play a major role in the subsidence of the Congo Basin. The project was funded by an IS-DAAD collaboration grant and by the Geological Survey of Norway.
Participants: Susanne Buiter (NGU), Bernhard Steinberger (GFZ Potsdam), Sergei Medvedev (University of Oslo), and Joya Tetreault (NGU).
- Buiter, S.J.H., B. Steinberger, S. Medvedev, J. Tetreault, 2012, Could the mantle have caused subsidence of the Congo Basin? Tectonophysics 514-517, 62-80, doi:10.1016/j.tecto.2011.09.024
This project explored the interaction between the African Plate lithosphere and mantle with the aim to better understand possible forces that can shape and modify sedimentary basins and related hydrocarbon accumulation. We focussed on the kinematics of the African Plate since the Palaeozoic, the geophysical characterisation of the present-day structure of the African Plate and its underlying mantle, the timing of major volcanic events, the formation of sedimentary basins, and the computation of regional stresses. Funded by Statoil.
Participants: Carmen Gaina, Susanne Buiter, Morgan Ganerød, Bart Hendriks, Cinthia Labails, Trond Torsvik, Giulio Viola, Robin Watson, and Sergei Medvedev (at that time all Geological Survey of Norway, NGU).
- van Hinsbergen, D.J.J., Buiter, S.J.H., Torsvik, T.H., Gaina, C. and Webb, S.J. (eds), 2011, The Formation and Evolution of Africa: A Synopsis of 3.8 Ga of Earth History, Geological Society, London, Special Publication 357, 378 pp.
- Steinberger, B., S. Buiter, S. Medvedev, J. Tetreault, 2010, The mantle under Africa: An overview of global and regional tomography models, lithosphere thickness models and their effect on present-day and past dynamic topography, NGU report 2010.058
The c2c (crust-to-core) Marie Curie Research Training Network aims to enhance understanding of the changing chemical and physical properties of slab material as it is compressed and heated in response to sinking into Earth’s interior, its interaction with the surrounding ‘unperturbed’ Earth, and the quantification of material fluxes. The network consists of 11 institutes in 9 countries. NGU participates with numerical models of subduction zone dynamics, focussing on slab dehydration and mantle wedge hydration, and sediment subduction. Our participation was funded by the EU and the Geological Survey of Norway.
NGU participants: Susanne Buiter, Matthieu Quinquis, and Zurab Chemia
- Quinquis, M.E.T. and Buiter, S.J.H., 2014, Testing the effects of basic numerical implementations of water migration on models of subduction dynamics, Solid Earth 5, 537-555, doi: 10.5194/se-5-537-2014, online open access
- Quinquis, M.E.T., Buiter, S.J.H., S. Ellis, 2011, The role of boundary conditions in numerical models of subduction zone dynamics, Tectonophysics 497, 57-70, doi:10.1016/j.tecto.2010.11.001
The project aims to provide an improved understanding
of the dynamic development of sedimentary basins and
To this purpose, we view the formation
of extensional sedimentary basins as a surface
expression of mode selection occurring on a crustal scale.
We predict modes of deformation by using an analytical analysis of
the rate of internal dissipation of energy and
the gravitational rate of work.
Results of finite-element calculations of
equivalent simple models agree with the analytical mode predictions.
The figure shows an example of the formation of a sedimentary basin by extension. The centre 200 km out of the 400 km modelling domain are shown. The frictional strength of the model materials softens with increasing strain. The basin is always kept completely filled with sediments (the different shades of yellow indicate different times of deposition), which also undergo strain softening. The grid in the figure is used to track material properties and visualises deformation; it is not the calculation grid (which is more dense). Calculations used sopale, developed by the Dalhousie Geodynamics Group.
Participants: Susanne Buiter, Ritske Huismans, and Chris Beaumont (and that time all Geodynamics Group, Dalhousie University, Canada).
- Buiter, S.J.H., R.S. Huismans and C. Beaumont, 2008, Dissipation analysis as a guide to mode selection during crustal extension and implications for the styles of sedimentary basins, Journal of Geophysical Research 113 (B6), doi: 10.1029/2007JB005272
- Huismans, R.S., S.J.H. Buiter and C. Beaumont, 2005, The effect of plastic-viscous layering and strain-softening on mode selection during lithospheric extension, Journal of Geophysical Research 110, B02406, doi: 10.1029/2004JB003114
- Buiter, S.J.H., Huismans, R.S., Beaumont, C. and Pfiffner, O.A., 2002, Self-consistent numerical models of extensional basin formation and subsequent contractional inversion, Bollettino di Geofisica teorica ed applicata 42, 1/2 supplement, 27-31
Basin inversion is the process of shortening an extensional sedimentary basin whereby the basin fill is uplifted and partially extruded, and pre-existing faults are re-used. Mild to moderate basin inversion has, among others, been identified on seismic profiles in the North Sea and the Alpine foreland. It is characterised by uplift of the basin fill, folding of syn- and post-rift sediments and (partial) reactivation of normal faults. Examples of strong or complete inversion can be found in the Alps and Pyrenees. Folding, faulting, fault rotation, fault reactivation and extrusion of the basin fill play a role in the generation of sometimes complex deformational structures. We used numerical experiments to a) investigate structures resulting from basin inversion and b) understand why extensional basins remain weak enough over several tens of millions of years to localise shortening and invert.
Participants: Susanne Buiter, Adrian Pfiffner, Chris Beaumont, Marion Panien, and Guido Schreurs. The projects were conducted at the University of Bern, Switzerland, and Dalhousie University, Canada.
- Buiter, S.J.H., O.A. Pfiffner and C. Beaumont, 2009, Inversion of extensional sedimentary basins: A numerical evaluation of the localisation of shortening, Earth and Planetary Science Letters 288, 492-504, doi: 10.1016/j.epsl.2009.10.011
- Panien, M., S.J.H. Buiter, G. Schreurs and O.A. Pfiffner, 2006, Inversion of a symmetric basin: insights from a comparison between analogue and numerical experiments, in: Analogue and Numerical Modelling of Crustal-Scale Processes, Buiter, S.J.H. and Schreurs, G. (eds), Geological Society, London, Special Publication 253, 253-270
- Susanne J.H. Buiter and O. Adrian Pfiffner, 2003, Numerical models of the inversion of half-graben basins, Tectonics 22 (5), 10.1029/2002TC001417
We quantified vertical surface displacements at convergent plate margins resulting from imposed variations on the subduction process. We used a two-dimensional mechanical model (TECTON) to examine surface displacements resulting from variations in slab buoyancy, velocity of the surface plates, friction along the interplate contact and subduction zone roll-back. We find that vertical surface displacements induced by changes in a subduction zone system can reach a magnitude of a few (ca. 2-4) kilometres on the margins of both the overriding and the subducting plate.
Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed at the Earth’s surface. We determined the range of displacement magnitudes which can be associated with slab detachment using numerical models. The lithospheric plates in our models have an effective elastic thickness, which provides an upper bound for rapid processes, like slab detachment, to the surface deformation of lithosphere with a more realistic rheology. Subduction with a non-migrating trench system followed by detachment leads to a maximum surface uplift of 2–6 km, while this may be higher for the case of roll-back preceding detachment. Overall, surface uplift of these magnitudes is not diagnostic of slab detachment since variations during ongoing subduction may result in similar vertical surface displacements.
Participants: Susanne Buiter, Rob Govers, Rinus Wortel. This project was conducted at Utrecht University, the Netherlands.
- Buiter, S.J.H., R. Govers and M.J.R. Wortel, 2002, Two-dimensional simulations of surface deformation caused by slab detachment, Tectonophysics 354, 195-210
- Buiter, S.J.H., R. Govers and M.J.R. Wortel, 2001, A modelling study of vertical displacements at convergent plate margins, Geophysical Journal International 147, 415-427
Lithosphere of the Adriatic plate has been subducting in a westward direction beneath Italy during several millions of years. Some regional tomographic images of the subducted Adriatic lithosphere have suggested that it is detached at depth. Wortel and Spakman (1992, Proc. KNAW 95) hypothesize that this is the result of propagation of a horizontal tear in the subducted lithosphere southwards along strike of the convergent plate margin. The resulting re-distribution of slab pull loads is expected to change vertical and horizontal motions at the surface. We investigated the effects of slab detachment below Italy on surface topography. We find that slab detachment below Northern Italy would lead to significant surface uplifts. However, from our flexure models we conclude that a trend in vertical loads along strike of the Apennines cannot be inferred from Plio-Pleistocene deflection data.
Participants: Susanne Buiter, Rinus Wortel, Rob Govers, Michiel van der Meulen. This project was conducted at Utrecht University, the Netherlands.
- Van der Meulen, M.J.,S.J.H. Buiter, J.E. Meulenkamp, M.J.R. Wortel, 1999, An early Pliocene uplift of the central Apenninic foredeep, and its geodynamic significance, Tectonics 19, p. 300-313.
- Buiter, S.J.H., M.J.R. Wortel and R. Govers, 1998, The role of subduction in the evolution of the Apennines foreland basin, Tectonophysics 296, p. 249-268
This project was conducted at Utrecht University, the Netherlands. We calculated the three-dimensional seismic velocity structure beneath Indonesia from information contained in tectonic (surface) reconstructions. The effect of the surface motions described in a reconstruction on the thermal structure of the underlying mantle is modelled with a kinematic modelling method. This results in a prediction of the present-day temperatures which are converted into seismic (P-wave) velocity anomalies. By comparing the predicted velocity models with tomography results of the area, the quality of the tectonic reconstructions can be evaluated.
The figure shows a vertical section across the Banda arc. From above to below: 1) topographic location map, 2) R-model based on reconstruction of Rangin et al (1990), 3) LL-model based on reconstruction of Lee and Lawver (1995), 4) tomographic BSE-model (Bijwaard et al, 1998).