Discussion on pre-ocean opening compression of the Northwestern Atlantic margin: evidence from eastern Greenland

Abstract

Scientific editing by Nick Rogers. H. D. Maher Jr, S. Bergh & Alvar Braathen write: ⇓Manby & Lyberis (2000) argue for a Cretaceous–Palaeocene age and a convergent setting for both the fold structures of the Wandel Sea Basin and for the West Spitsbergen fold–thrust belt as an alternative to models of decoupling during Palaeocene–Eocene transpressive motions between Greenland and the Barents Shelf. In this context, we discuss evidence on the timing and kinematics of the West Spitsbergen fold–thrust belt, and constraints on the timing of deformation in the Wandel Sea Basin. Multiple lines of evidence constraining the timing of fold–thrust formation in Spitsbergen are discussed in ⇓Maher et al. (1995) and clearly indicate major fold-thrust development in the Palaeocene–Eocene. Space limitations prevent their description here. The nature of additional Late Cretaceous deformation on Spitsbergen is another question. It is partly constrained by the unconformity at the base of the Tertiary sequence, which is well exposed in many places and is consistently disconformable to the eye. This unconformity involves differential uplift to the north with a regional tilt of a degree or less, has a character inconsistent with previous fold-thrust development along the islands western margin, and can be related to a second pulse within the High Arctic Large Igneous Province (⇓Maher 2001). More recent work confirms a Palaeocene–Eocene age for the Spitsbergen contractional structures. Manby & Lyberis refer to ⇓Blythe & Kleinspehn (1998) as indicating a Late Cretaceous age for Spitsbergen fold–thrust belt uplift. In their summary figure Blythe & Kleinspehn indicate uplift and erosion of source terranes initiating at 70 Ma and continuing until c. 43 Ma. Six detailed thermal histories generated from track-length modelling of samples taken from the Tertiary foreland basin sediments provide particular insight. As the authors note, three samples with depositional ages of …