LAUSR

Abstract The opening and pre-opening history of the Amerasia Basin is poorly constrained. Key tectonic events have been interpreted from outcrop data in adjacent sedimentary basins or from geophysical data along its continental margins. However, due to its location in a polar region, data are scarce and the existing models of tectonic evolution are controversial. The northernmost exposed adjacent basin is the Mississippian to Late Cretaceous Sverdrup Basin, the original structural framework of which is unclear because it was overprinted by the latest Cretaceous to Paleogene Eurekan Orogeny. This paper presents a restored structural cross-section of the eastern half of the Sverdrup Basin in order to remove deformation attributed to Eurekan shortening and identify previous Mississipian to Late Cretaceous structures. Our results reveal that the evolution of the Sverdrup Basin during the Mesozoic was dominated by the rising of salt diapirs in the basin centre and by Triassic to Jurassic extensional fault development at the basin’s margins. Diapirs were squeezed during Eurekan tectonic inversion whilst extensional faults formed thrusts. The discovery of Triassic fault activity is a new finding in the Sverdrup Basin and forms an extra element to be considered in tectonic models for the opening of the Amerasia Basin.