Additional Observations on the Late Proterozoic Varangerfjorden Unconformity, Finnmark, Northern Norway
17 ADDITIONAL OBSERVATIONS ON THE LATE PROTEROZOIC VARANGERFJORDEN UNCONFORMITY, FINNMARK, NORTHERN NORWAY KAUKO LAAJOKI LAAJOKI, KAUKO 2001. Additional observations on the late Proterozoic Va- rangerfjorden unconformity, Finnmark, northern Norway. Bulletin of the Geo- logical Society of Finland 73, Parts 1–2, 17–34. This paper is complementary to the author’s recent publication, which pro- vided several new pieces of evidence for the glacial abrasion of the late Proter- ozoic 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 unconformi- ty have been destroyed by secondary pits and imprints, most severely just west of the Bigganjargga diamictite, where the intra-Smalfjord hiatus joins the un- conformity. This point represents the axial zone of the channel, which eroded the Bigganjargga diamictite and provided a favourable environment for diage- netic 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 de- scribed. Roches moutonnées of either late Proterozoic or Pleistocene age that had developed on a Precambrian basement gneiss are reported at Karlebotn. Pleis- tocene striations and pits on the Veinesbotn quartzite are described for compar- ison purposes. Key words: sedimentary rocks, unconformities, glacial erosion, striations, gneiss- es, roches moutonnées, Proterozoic, Bigganjargga, Handelsneset, Skjåholmen, Smalfjord, Finnmark, Norway Kauko Laajoki: University of Oulu, Department of Geology, Box 3000, 90401 Oulu, Finland, and Mineralogical-Geological Museum, University of Oslo, Sars’ gate 1, 0562 Oslo, Norway.
[Show full text]