The Mid-Proterozoic of South Norway has been an important area of research into Precambrian crustal evolution for several decades. Yet still relatively little is known about the timing of accretion and the origin of the crust hampering correlations with adjacent terrains.
The first, recently obtained Sm-Nd ages for gabbroic intrusions suggest, though with a large error, that crust-forming processes may have started well before 1.7 Ga, I.e. earlier than previously assumed. The data also suggest the long-term presence of several, chemically distinct, mantle reservoirs. The first Sm-Nd data on metasediments indicate a possible, yet not, documented, involvement of older, 1.9-1.7 Ga old Svecofennian crust. The proposal aims at a better definition of the crust-forming euents by application of high-precision geochronological techniques, like SIMS, on detrital zircons from metasediments, and zircons and baddeleyites from gabbroic intrusions, and at a definition of the different crustal and mantle reservoirs which contributed to the accretion .