WP1: Continental rifting and breakup processes

Work package leaders: Jan Inge Faleide (UiO) and Susanne Buiter (NGU)
Contributions from: Snorre Olaussen (UNIS), Alexander Minakov (UiO), Johannes Schweitzer (NORSAR), Rolf Mjelde (UiB)

Introduction

The Lomonosov Ridge, a narrow continental sliver extending for more than 1500 km, is a unique geological structure on Earth. It separated from the northern Barents Shelf during initial opening of the Eurasia Basin in earliest Eocene time (about 55 mill years ago). The crustal architecture of the conjugate northern Barents Sea and Lomonosov Ridge margins is characterized by a sharp continent-ocean transition more typical for sheared margins than rifted margins (Minakov et al. 2012a). These conjugate margins may be classified as magma-poor along most of their lengths. In the western Eurasia Basin, the partly volcanic Yermak Plateau and Morris Jesup Rise form conjugate features that start to overlap in plate reconstructions long before closure of the entire Eurasia Basin (Engen et al. 2008; Jokat et al. 2016). This segment of the Eurasia Basin developed close to contraction/shortening in the Eurekan and Spitsbergen fold-and-thrust belts during Eocene time (Bergh et al. 1997; Leever et al. 2011; Piepjohn et al. 2016). Furthermore, the line of breakup cross-cuts the structural grain of the northern Barents Shelf and Svalbard at a high angle.

In WP1 we will study the tectonic setting and geological processes that prevailed during breakup between the Lomonosov Ridge and the northern Barents Shelf, and between the Yermak Plateau and Morris Jesup Rise. The study implies acquisition of geological and geophysical data from onshore Svalbard across the Eurasia Basin to the Lomonosov Ridge.

Main objective

Identify the main controls on rifting/breakup processes that formed the Lomonosov Ridge, Yermak Plateau and Morris Jesup Rise. To achieve this we have to improve our understanding of the links between deep and shallow processes, and between vertical and horizontal movements (plate tectonics). Additional (secondary) objectives include: Inheritance and cross-cutting relationships, dynamics of rifting (processes of rifting, obliqueness, propagation…), mantle rheology and structure/processes, tectonic pre-glacial uplift. Furthermore, we need to understand how an orogenic belt (Eurekan-Spitsbergen) could co-exist with an incipient oceanic basin in early Cenozoic times.