Geodynamic Evolution of the Eurekan Orogen of Ellesmere Island

Abstract:

The Eurekan Orogeny, which created much of the high topography of Ellesmere Island and adjacent Greenland, occurred as a result of mountain-building processes the dynamics of which are not well understood. It is generally considered that the rotation of Greenland in the Eocene (related to sedimentary basin formation in Baffin Bay) produced compressional tectonics between Greenland and Ellesmere Island. As part of this process, the Eurekan Orogeny formed away from a traditional convergent ocean-closure plate boundary, and represents a style of “intraplate" deformation. In this work, the geodynamic evolution of the Eurekan Orogeny and its relationship to the tectonics of the Canadian polar margin and northern Baffin Basin is explored using high-resolution thermal-mechanical numerical experiments with the modelling code SOPALE. The modelling of the High Arctic is constrained by the first-order crustal structure of the region (deduced by local gravity field and passive seismological data). Presented are suites of numerical experiments that investigate how the pre-existing lithospheric structures (both crustal and sub-crustal) control the evolution of the resulting intraplate orogen. The influence of other primary modelling parameters, such as plate convergence velocity and assumed rheology, are also explored. To highlight the role of surface processes on plate and lithosphere deformation, the importance of climate-controlled erosion and deposition in influencing the tectonics of High Arctic orogenesis is considered. As the tectonic evolution of the region is poorly resolved, we present some of the first interpretations of the development of Ellesmerian and northern Baffin lithosphere from the Earth’s surface down to the base of the lithosphere. The numerical experiments evaluate and refine the geodynamical interpretations for enigmatic intraplate tectonics—applicable to this Arctic region and other instances globally.