Seismic velocities of granulites from the Seiland Petrographic Province (N. Norway): Implications for Scandinavian lower continental crust

Compressional and shear wave velocities have been measured in the laboratory at up to 1.0 GPa effective pressure on a suite of granulite facies rocks from the Seiland Petrographic Province. The suite may be of Precambrian age and the measurements were made to test a proposal that the suite represents lower continental crust. Compressional wave velocities at 0.4 GPa effective pressure range from 6.41–6.97 km s-1 with a mean of 6.71 km s-1 . Measurements of the parameter (∂V/∂Tp) suggest a value of a –0.8 x 10-3 km s-1 ºC-1 , and the temperature corrected mean velocity of about 6.5 km s-1 at 20 km depth is comparable to that found in parts of the lower crust in Scandinavia. The mean Poisson's ratio of 0.29 at 0.4 GPa is slightly higher than that found (0.276), but could be reduced if heterogeneity in the suite and the effect of higher pressures are taken into account. The occurrence of lower continental crust as a thrust slice in the Province is consistent with current ideas on the geological evolution of this area.           ARK: https://n2t.net/ark:/88439/y080958 Permalink: https://geophysicsjournal.com/article/260 &nbsp