NJG18-1-03
1938
Progressive metamorphism of sparagmite rocks of southern Norway
18
1
54-65

The Eocambrian Sparagmite Formation covers large areas in south-eastern Norway. Petrographically it is a coarse, quartzose sediment which in its unmetamorphic facies consists almost exclusive!y of fragments of quartz and feldspar, frequently conglomeratic. Due to the effect of the Caledonian falding the metamorphism of the Sparagmitian increases, generally speaking, from South-east to Northwest. In the upper parts of Gudbrandsdalen and Østerdalen, in Rondane, and in the Atnasjø District, the sparagmite is typically schistose; unmetamorphic facies being quite unknown in these parts. Still closer to the central parts of the Caledonian falding the sparagmite rocks are overlain by pelitic sediments of the Trondheim syncline, but still farther to the West sparagmite beds crop out from underneath the syncline on its west side. The metamorphic grade is here somewhat higher, the rocks being flaggy and granulite-Iike. This series passes by gradation into an underlying series of epidote-bearing gneisses and gneiss-granites; this fact will be discussed in a later section, however. A few words should now be said about the mineral changes induced in the sparagmite by the progressive metamorphism.