Tectonic geomorphology of the Chukchi borderland: constraint for tectonic reconstruction models

Abstract

"The Chukchi Borderland is a region of extended continental crust within the Amerasia Basin and is bounded on one side by oceanic crust of the Canada Basin. Because of its central location within the basin, tectonic models for the reconstruction of the Arctic Ocean, must include the Chukchi Borderland although there is no consensus about its pre-rift location or kinematic development. In recent years bathymetric data have been collected that can offer constraint on the tectonic evolution of the Amerasia Basin by providing details about the geomorphology of the intra-basinal ridges allowing comparison of bathymetric features to those in other ocean basins. Bathymetric information in conjunction with multi-channel seismic and chirp sub-bottom profiler data show the location and strike of inferred faults used to determine rift directions which then provide constraint on tectonic reconstructions. The central Amerasia Basin, which includes the Chukchi Borderland, Mendeleev Ridge and south central Alpha Ridge, has experienced significant extension in generally the same direction and probably during one event. This type of plate boundary scale extension requires the development of accommodation faulting or transfer zones that facilitate the amalgamation of long fault segments. Features consistent with this type of faulting are observed throughout the Chukchi Borderland. There is no evidence of compression along the Northwind Ridge nor is there any indication of a strike-slip boundary within the Northern Chukchi Borderland as some tectonic models suggest. Whichever model is preferred, the geomorphology of the intra-basinal ridges must be taken into account and used as constraint for the reconstruction of the Amerasia Basin"--Leaf iii