Additional observations on the Late Proterozoic Varangerfjorden unconformity, Finnmark, northern Norway

Abstract

This paper is complementary to the author’s recent publication, which provided several new pieces of evidence for the glacial abrasion of the late Proterozoic Varangerfjorden unconformity. Additional descriptions of striations and diverse pits and embedded clasts on the unconformity surface at Bigganjargga are given, and it is stressed that the primary glacial features of the unconformity have been destroyed by secondary pits and imprints, most severely just west of the Bigganjargga diamictite, where the intra-Smalfjord hiatus joins the unconformity. This point represents the axial zone of the channel, which eroded the Bigganjargga diamictite and provided a favourable environment for diagenetic and possibly later fluids to attack the unconformity surface. Small grooves visible as positive casts at the base of the Smalfjord Formation are reported from Handelsneset. The general regional features of the unconformity at Vieranjarga and Ruossoai’vi and syn-Smalfjord erosional features at Skjåholmen are described. Roches moutonnées of either late Proterozoic or Pleistocene age that had developed on a Precambrian basement gneiss are reported at Karlebotn. Pleistocene striations and pits on the Veinesbotn quartzite are described for comparison purposes.

Keywords

• sedimentary rocks
• unconformities
• glacial erosion
• striations
• gneisses
• roches moutonnées
• Proterozoic
• Bigganjargga
• Handelsneset
• Skjåholmen
• Smalfjord
• Finnmark
• Norway