Valdres-sparagmittens stratigrafiske stilling.

Abstract

The Valdres Sparagmite is a deposit chiefly of arkoses (sparagmites) in central Southern Norway. It lies above fossiliferous Ordovician sediments and has thus been considered as of Ordovician or Silurian age by Norwegian geologists. The Valdres Sparagmite shows interesting relations with the overthrust crystalline massifs of southern Norway. There is one set of massifs which have been emplaced before or during the deposition of the Valdres Sparagmite, because some of them are covered by this deposit and because they can be proved to have yielded material to it. Another set of massifs have been overthrust above the Valdres Sparagmite. The two sets of massifs are commonly being referred to as the lower and upper Jotun Nappes. Thus two phases can be discerned in the Caledonian orogeny in southern Norway, the older of which, broadly contemporaneous with the deposition of the Valdres Sparagmite, may be Taconic. The view expressed above has recently been challenged by the Swedish geologist Oskar Kulling, who interpreted the Valdres Sparagmite as of Eocambrian age and as being overthrust together with its crystalline basement and in places inverted below it. The writer has for some years wished to clarify the statigraphic position of the Valdres Sparagmite and the writings of Dr. Kulling have been an impetus to publish this present paper.