The tectonic and geodynamic evolution the Arctic ocean, the northern Pacific rim and borderlands are still poorly understood. The complex history of subduction, seafloor spreading, back-arc basin opening and destruction, and sedimentary basin evolution in the context of adjacent ocean basins are ill-constrained due to the remoteness of the region and our incomplete knowledge of the geological history.There are several controversies in regard to tectonic models of the Arctic realm, and perhaps the least resolved aspect is the evolution of the Amerasia Basin that occupies more than half of that region. Several mechanism have been proposed, from counter-clock wise rotation of the Alaskan North Slope to open the Canada basin in a back-arc fashion to diachronous rifting of several microcontinents from the North American margin, or simply an extreme plate boundary relocation from the high Arctic to the North Pacific that led to an older Pacific oceanic crust to be trapped in the Amerasia basin. None of these scenarios entirely satisfies the various geological and geophysical constraints.

In neighbouring regions, including the North Pacific and NE Asia, ages and distributions of various terranes and adjacent oceanic basins are also still poorly constrained, including the cause and timing of rifting in the Sea of Okhotsk, and the location and timing of back-arc basins along the Pacific rim of the Arctic.
In particular the connection between the lithosphere and mantle in the Arctic region has been rarely explored. The Mesozoic history of subducted oceans and basins and the poorly understood causes for magmatism and evolution of surface topography in the circum-Arctic region can potentially be unravelled by investigating mantle-lithosphere interaction through time. New global and regional tomographic models and modern techniques to image subducted slabs and a better understanding of global reference frames that aim to link plate motion to mantle dynamics are now sufficiently mature to be included in studies of less explored regions, like the High Arctic. A circum-Arctic geodynamic framework would assist in the understanding of enigmatic uplift and subsidence events that occurred in that region as recently unravelled by drilling expeditions.

This session provides a forum for discussions of a variety of problems linked to the Circum-Arctic geodynamics and aims to bring together a diversity of sub-disciplines including plate tectonic, mantle tomography, geodynamic modelling, igneous and structural geology, geophysical imaging, paleomagnetism, sedimentology, etc.
Particularly encouraged are papers to address lithospheric-mantle interactions in the Arctic region, mantle dynamics and vertical and horizontal motion of various crustal blocks.

Invited Contributors: Sergei Drachev, ExxonMobil International Limited, United Kingdom
Ivan Koulakov, Institute of Petroleum Geology and Geophysics, Russia