The Eurekan Orogen: a transpressional fold-and-thrust belt

A major period of late Cretaceous-Paleogene tectonism which affected the Canadian Arctic Islands and North Greenland is referred to as the Eurekan Orogeny. The Eurekan Orogeny was caused by relative plate motions between Greenland and the Canadian Arctic Islands, driven by linked oceanic spreading systems in the Labrador Sea/Baffin Bay, the Norwegian-Greenland Sea and the Eurasian Basin (Tessensohn and Piepjohn, 2000).

The Eurekan Orogen displays some features of a traditional fold-and-thrust belt: e.g. it consists of a region of folded and thrust-faulted rocks and has associated uplifted and mountainous topography. However, the Eurekan Orogen is atypical of many in several respects (De Paor et al., 1989):

• It lacks a metamorphic hinterland and wedge-shaped profile,
• It has no clear flexural foredeep,
• The age of stratigraphic units exposed at the surface and the intensity of strain both increase towards the foreland,
• It is anomalously wide compared to its length.

The Eurekan Orogeny affected several basins considered to be extremely prospective for future hydrocarbon discoveries (Bird et al., 2008). Paleogene sediments shed from the emerging Eurekan Orogen were deposited in intramontane basins on the Canadian Arctic Islands and form potential reservoir units in Baffin Bay and the Canada Basin (Harrison et al., 2011; Houseknecht and Bird, 2011; Miall, 1991). Eurekan folds and faults are the last major contractional structures to have affected the Sverdrup Basin and Baffin Bay. Therefore, understanding the effects, timing and extent of Eurekan deformation is important for reducing the risks to hydrocarbon exploration in the region.

A CASP review of the Eurekan Orogeny combines data from published literature and geological maps with field data collected during several seasons on Ellesmere Island, with the aim of understanding:

• The extent, style and timing of Eurekan deformation and its wider tectonic significance,
• The implications of the Eurekan Orogeny for hydrocarbon systems

The review has helped to clarify how several factors, such as lithological variation, strain partitioning and structural inheritance, influenced the unusual structural style of the Eurekan Orogeny. Based on these findings, a working model of the tectonic evolution of the region in the late Cretaceous-Paleogene is proposed.