Tectonic inversion in the Wandel Sea Basin: A new structural model of Kilen (eastern North Greenland)

Abstract

The seminunatak Kilen in eastern North Greenland, with its complexly deformed Carboniferous‐Cretaceous strata, is a key area to understand the tectonic history of the transform plate boundary between eastern North Greenland and Svalbard. Detailed 3‐D geological mapping from oblique photogrammetry along with limited ground fieldwork and interpretation of previously published data forms the basis for a new structural model of Kilen. Previous structural models interpreted rhombic‐shaped fault patterns as the evidence for strike‐slip tectonics. These structures are here interpreted to be the result of a post‐Coniacian NE‐SW extension with NW‐SE trending normal faults followed by later, N‐S compression of presumable Paleocene‐Eocene age, folding the faults passively and suggesting the presence of a basal detachment. Furthermore, two thrust sheets have been distinguished on Kilen: a lower Kilen Thrust Sheet and an upper Hondal Elv Thrust Sheet separated by a subhorizontal fault: the Central Detachment. The style of deformation and the structures described are interpreted as the result of Paleocene‐Eocene N‐S directed compression resulting in basin inversion with strike‐slip faults only having minor status. This indicates that the Greenland margin as exposed on Kilen and the conjugate Svalbard margin in the West Spitsbergen fold‐and‐thrust belt are more similar than previously anticipated.

3D restoration of a Cretaceous rift basin in Kilen, eastern North Greenland

“…Initial mapping and dating of key units resulted in the recognition of 23 lithostratigraphic units of Jurassic-Cretaceous age and an Upper Palaeozoic mélange unit (Pedersen, 1989;Håkansson et al, 1993Håkansson et al, , 1994a. More recent fieldwork by the Geological Survey of Denmark and Greenland (GEUS) (Bojesen-Koefoed et al, 2014) has indicated the need for a stratigraphic revision and a more simplified stratigraphic scheme is applied here to divide the succession into five units cf., Svennevig et al (2016a) (Fig. 3).…”

“…Abbreviations: KCTZ -Kap Cannon Thrust Zone, TLFZ -Trolle Land Fault Zone, TLFS -Trolle Land Fault System, EGFZ -East Greenland Fault Zone, HFFZ -Harder Fjord Fault Zone. difficult ( Fig. 2; Håkansson et al, 1993Håkansson et al, , 1994aSvennevig et al, 2016a). Initial mapping and dating of key units resulted in the recognition of 23 lithostratigraphic units of Jurassic-Cretaceous age and an Upper Palaeozoic mélange unit (Pedersen, 1989;Håkansson et al, 1993Håkansson et al, , 1994a.…”

“…In pre-Atlantic opening times, these faults were parallel to the Billefjorden and Lomfjorden fault zones on the conjugate Svalbard margin (Soper et al, 1982;Faleide et al, 1993;Piepjohn & von Gosen, 2001;Gosen & Piepjohn, 2003;Leever et al, 2011). and Stemmerik et al (2000) with schematic faults from Kilen modified from Svennevig et al (2016a). Dykes are simplified from Bengaard & Henriksen (1984).…”

“…According to Håkansson & Pedersen (1982, 2015, Mesozoic deposition on Kilen was controlled by dextral transtension resulting in the formation of several pull-apart basins culminating in end-Cretaceous transpression. Recently, Svennevig et al (2016a) presented an alternative structural interpretation of …”

“…This structural model allows for a new and simpler view of the Mesozoic Wandel Sea Basin as a rift basin dominated by extensional faults; in line with basins along the conjugate southwestern Barents Sea margin such as the Bjørnøya, Sørvestnaget and Tromsø basins (Faleide et al, 2008;Gernigon et al, 2014). This paper explores the implications of this new tectonic model for Mesozoic basin evolution by presenting a pre-folding 3D reconstruction of the basin at Kilen using the structural model of Svennevig et al (2016a). The reconstruction focuses on the main faults and uses a single, well constrained, mid-Cretaceous horizon as a marker.…”