DEFormation MODelling in the North Atlantic and Arctic

In conventional plate tectonic reconstructions, major plates such as Greenland, Eurasia and North America, are assumed to be rigid. However, prior to the onset of seafloor spreading, rifting lithosphere experiences significant deformation that is usually not accounted for in plate reconstruction models. This includes the passive margins of the North Atlantic and Barents Shelf, which have been dominated by numerous rifting episodes (Carboniferous, Late Permian, Late Jurassic-Early Cenozoic and Late Cretaceous-Paleogene) since Early Devonian post-Caledonian collapse. The DEFMOD, or “DEFormation MODelling of the North Atlantic and Arctic,” project aims to bridge the knowledge gap about sedimentary basins and regional plate tectonics by constructing 4-D (3 spatial dimensions + time) geodynamic models for Late Paleozoic-Cenozoic times.

Picture: Clockwise from left to right (1) Grace at the North Pole and Swedish icebreaker Oden in the background, (2) polar bear, (3) daily helicopter flights for the ice-sampling team, (4) typical sunrise/sunset view from deck, (5) opened core showing the variation in sedimentary layers, (6) reloading the core liner with the Canadian icebreaker Louis in the background.

Unravelling the far-field, regional tectonic effects on rift history is key for assessing the potential of new hydrocarbon fields and recovery from existing and future fields. Such effects may include strain rates in intervening deforming regions; uplift, subsidence and observed stratigraphic hiatus events; basin-scale features; oceanic gateways, and heat flow.Within a testable regional framework,structural and sedimentary data will be combined with results from geophysical inversions and state of the art numerical modeling of the lithosphere and mantle. The time-dependent location and size of sedimentary basins will be restored along the North Atlantic margins and the Barents Shelf as well as in Baffin Bay and Ellesmere Island, also leading to a revised set of regional palaeogeographic maps. 

Caption: Simplified reconstruction of North Atlantic and basins (Faleide et al., 2008) at 53 Ma overlain with change in velocity field between 53 and 52 Ma implied by existing plate model (Seton et al., 2012) with major rigid plates. Stress, deformation and restoration on basin scales are not yet accounted for.

I completed my PhD in geodynamics within EarthByte group at the University of Sydney. Since late 2013, I have undertaken a postdoctoral research position at the Centre for Earth Evolution and Dynamics (CEED), a Norwegian Centre of Excellence hosted at the University of Oslo. Key research interests include understanding the history of ocean basin opening and closure of the Arctic and northern Panthalassa (the pre-Pacific ocean basin), deciphering deep mantle structure and use of the GPlates reconstruction software.

Publications:

Abdelmalak, M. M., Andersen, T.B., Planke, S., Faleide, J.I., Corfu, F., Tegner, C., Shephard, G.E. Zastrozhnov D.and Myklebust R. 2015. The Ocean-Continent-Transition in the Mid-Norwegian Margin: Insight From Seismic Data and an Onshore Caledonian Field Analogue. Geology v.43 (11) p.1011-1014.

Jones, M.T., Augland, L.E. Shephard, G.E., Burgess, S.D., Eliassen, G.T., Jochmann, M.M., Friis B., Jerram, D.A., Planke, S., Svensen, H.H. 2017. Constraining shifts in North Atlantic plate motions during the Palaeocene by U-Pb dating of Svalbard tephra layers.  Scientific Reports. doi:10.1038/s41598-017-06170-7

Jones, M.T., Eliassen, G.T., Shephard, G.E., Svensen, H.H., Jochmann, M., Friis, B., Augland, L.E., Jerram, D.A., Planke, S. 2016. Provenance of bentonite layers in the Palaeocene strata of the Central Basin, Svalbard: implications for magmatism and rifting events around the onset of the North Atlantic Igneous Province. Journal of Volcanology and Geothermal Research v327 p571-584 doi:10.1016/j.jvolgeores.2016.09.014

Shephard, G.E., Matthews, K.J., Hosseini, K., Domeier, M. 2017. On the consistency of seismically imaged lower mantle slabs.​ Scientific Reports v7. doi:10.1038/s41598-017-11039-w 

Shephard, G.E., R.G. Trønnes, W. Spakman, I. Panet, C. Gaina. 2016. Evidence for a distinct slab under Greenland and links to Cretaceous High Arctic magmatism. Geophysical Research Letters v.43 p.3717-3726 doi:10.1002/2016GL068424

Müller, R.D., Seton, M., Zahirovic, S., Williams, S., Matthews, KJ., Wright, N.M., Shephard, G.E., Maloney, K.T., Barnett-Moore, N., Hosseinpour, M., Bower, D.J., and Cannon, J. 2016. Ocean basin evolution and global-scale plate reorganization events since Pangea breakup. Annual Reviews v.44.

Full publication list available at Google Scholar [https://scholar.google.no/citations?user=PDAfpXEAAAAJ&hl=en]