Open AccessRb/Sr whole rock age determinations from the western part of the 0stfold basement complex, SE Norway
Author(s) -
Bjørn Hageskov,
Sune Pedersen
Publication year - 1981
Publication title -
bulletin of the geological society of denmark
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.674
H-Index - 28
eISSN - 2245-7070
pISSN - 0011-6297
DOI - 10.37570/bgsd-1980-29-07
Subject(s) - geology , intrusion , facies , metamorphic facies , basement , geochemistry , deformation (meteorology) , mineralogy , seismology , geomorphology , archaeology , structural basin , geography , oceanography
Rb/Sr whole rock age determinations on granitic orthogneisses in the western part of the 0stfold basement complex have yielded ages in the range 1380-1015 m.y. The ages obtained indicate that the regional multiple fold structures, formed by superimposition of folds with E-W trending, vertical to steeply northwards dipping axial surfaces on older folds with N-S axial surfaces, are younger than 1320 m.y. Intrusion of basic dykes (the Kattsund dykes), and the subsequent ductile high strain deformation in the Oslofjorden region are younger than 1225 m.y. It is suggested that the last amphibolite facies metamorphism in the area, which is associated with the high strain deformation, occurred about 1015 m.y. ago.