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Circum-Arctic mantle structure and long-wavelength topography since the Jurassic

Journal Article


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Abstract


  • The circum-Arctic is one of the most tectonically complex regions of the world, shaped by a history of ocean basin opening and closure since the Early Jurassic. The region is characterized by contemporaneous large-scale Cenozoic exhumation extending from Alaska to the Atlantic, but its driving force is unknown. We show that the mantle flow associated with subducted slabs of the South Anuyi, Mongol-Okhotsk, and Panthalassa oceans have imparted long-wavelength deflection on overriding plates. We identify the Jurassic-Cretaceous South Anuyi slab under present-day Greenland in seismic tomography and numerical mantle flow models. Under North America, we propose the “Farallon” slab results from Andean-style ocean-continent convergence around ~30°N and from a combination of ocean-continent and intraoceanic subduction north of 50°N. We compute circum-Arctic dynamic topography through time from subduction-driven convection models and find that slabs have imparted on average <1–16 m/Myr of dynamic subsidence across the region from at least 170 Ma to ~50 Ma. With the exception of Siberia, the main phase of circum-Arctic dynamic subsidence has been followed either by slowed subsidence or by uplift of <1–6 m/Myr on average to present day. Comparing these results to geological inferences suggest that subduction-driven dynamic topography can account for rapid Middle to Late Jurassic subsidence in the Slave Craton and North Slope (respectively, <15 and 21 m/Myr, between 170 and 130 Ma) and for dynamic subsidence (<7 m/Myr, ~170–50 Ma) followed by dynamic uplift (<6 m/Myr since 50 Ma) of the Barents Sea region. Combining detailed kinematic reconstructions with geodynamic modeling and key geological observations constitutes a powerful tool to investigate the origin of vertical motion in remote regions.

Authors


  •   Shephard, G E. (external author)
  •   Flament, Nicolas
  •   Williams, Simon E. (external author)
  •   Seton, Maria (external author)
  •   Gurnis, Michael (external author)
  •   Muller, R. Dietmar (external author)

Publication Date


  • 2014

Citation


  • Shephard, G. E., Flament, N., Williams, S., Seton, M., Gurnis, M. & Muller, R. D. (2014). Circum-Arctic mantle structure and long-wavelength topography since the Jurassic. Journal of Geophysical Research, 119 (10), 7889-7908.

Scopus Eid


  • 2-s2.0-84915748232

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=5266&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/4242

Number Of Pages


  • 19

Start Page


  • 7889

End Page


  • 7908

Volume


  • 119

Issue


  • 10

Abstract


  • The circum-Arctic is one of the most tectonically complex regions of the world, shaped by a history of ocean basin opening and closure since the Early Jurassic. The region is characterized by contemporaneous large-scale Cenozoic exhumation extending from Alaska to the Atlantic, but its driving force is unknown. We show that the mantle flow associated with subducted slabs of the South Anuyi, Mongol-Okhotsk, and Panthalassa oceans have imparted long-wavelength deflection on overriding plates. We identify the Jurassic-Cretaceous South Anuyi slab under present-day Greenland in seismic tomography and numerical mantle flow models. Under North America, we propose the “Farallon” slab results from Andean-style ocean-continent convergence around ~30°N and from a combination of ocean-continent and intraoceanic subduction north of 50°N. We compute circum-Arctic dynamic topography through time from subduction-driven convection models and find that slabs have imparted on average <1–16 m/Myr of dynamic subsidence across the region from at least 170 Ma to ~50 Ma. With the exception of Siberia, the main phase of circum-Arctic dynamic subsidence has been followed either by slowed subsidence or by uplift of <1–6 m/Myr on average to present day. Comparing these results to geological inferences suggest that subduction-driven dynamic topography can account for rapid Middle to Late Jurassic subsidence in the Slave Craton and North Slope (respectively, <15 and 21 m/Myr, between 170 and 130 Ma) and for dynamic subsidence (<7 m/Myr, ~170–50 Ma) followed by dynamic uplift (<6 m/Myr since 50 Ma) of the Barents Sea region. Combining detailed kinematic reconstructions with geodynamic modeling and key geological observations constitutes a powerful tool to investigate the origin of vertical motion in remote regions.

Authors


  •   Shephard, G E. (external author)
  •   Flament, Nicolas
  •   Williams, Simon E. (external author)
  •   Seton, Maria (external author)
  •   Gurnis, Michael (external author)
  •   Muller, R. Dietmar (external author)

Publication Date


  • 2014

Citation


  • Shephard, G. E., Flament, N., Williams, S., Seton, M., Gurnis, M. & Muller, R. D. (2014). Circum-Arctic mantle structure and long-wavelength topography since the Jurassic. Journal of Geophysical Research, 119 (10), 7889-7908.

Scopus Eid


  • 2-s2.0-84915748232

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=5266&context=smhpapers

Ro Metadata Url


  • http://ro.uow.edu.au/smhpapers/4242

Number Of Pages


  • 19

Start Page


  • 7889

End Page


  • 7908

Volume


  • 119

Issue


  • 10