Tertiary or Cretaceous age for Spitsbergen's fold‐thrust belt on the Barents Shelf

Abstract

Several publications propose that main‐phase fold‐thrust development on Spitsbergen was Late Cretaceous and not Tertiary as previously thought. The question of timing is crucial to models for crustal response to transpressive plate motions. Involvement of Tertiary strata in fold‐thrust structures, the sedimentology of the Tertiary basin strata, and studies of paleo‐stress field evolution all indicate Paleocene to Eocene fold‐thrust development during opening of the Norwegian‐Greenland oceanic basin. A regional angular unconformity of < 1° between Paleocene and Early Cretaceous strata is consistently disconformable to the eye and precludes any significant older deformation in the immediate area. Pre‐unconformity deformation was likely strike slip in character and concentrated in the west. The proposal for Late Cretaceous fold‐thrust belt formation is inconsistent with the geology.