STRUCTURAL RESTORATION OF GEOLOGICAL CROSS-SECTIONS OF NORTH-EASTERN ELLESMERE ISLAND (CANADIAN ARCTIC): INSIGHT INTO THE ELLESMERIAN AND EUREKAN DEFORMATIONS

The study area on NE Ellesmere Island is part of the Central Ellesmere Fold Belt, which was formed during the Ellesmerian (?)Late Devonian - earliest Carboniferous) and Eurekan (Eocene) deformations. Understanding the Eurekan deformation provides useful information about the opening of the Arctic Ocean basin and related plate tectonic processes. Restoration of compressional structures and estimation of the related shortening are essential for reconstructing pre-Eurekan plate tectonics. Two restored geological cross-sections provide amounts of shortening during the Eurekan and Ellesmerian deformations and permit an insight into the sequential kinematics. Cross-section 1 (Radmore Harbour) and Cross-section 2 Dobbin Bay), published by Piepjohn et al. (2008), were modeled based on sequential restoration techniques using the commercial software Move2015TM. The total shortening is in a range of ~34 km or ~43% for Cross-section 1 and ~35 km or ~35.2% for Cross-section 2 representing minimum amounts. We reinterpreted the Jolliffe Glacier Anticline and Eugenie Glacier Anticline as parts of the Ellesmerian blind thrust system with local detachments in the Cass Fjord and Baumann Fiord formations. The Ellesmerian shortening varies between ~18.4% or ~14.6 km (Cross-section 1) and ~7.7% or ~7.7 km (Cross-section 2). We found that shortening of ~30% was achieved during the Eurekan deformation and determine shortening of ~19.4 km and ~27.5 km for Cross-sections 1 and 2, respectively. We reinterpret the Rawlings Bay Thrust as branching off the basal detachment in a depth of ~8 km and suggest flat-lying stratigraphic units for the footwall of the Rawlings Bay Thrust and Parrish Glacier Thrust.