ND ISOTOPIC EVIDENCE FOR EXOTIC DETRITUS IN THE KALAK NAPPE COMPLEX, NORTH NORWEGIAN CALEDONIDES

Samples from the Kalak Nappe Complex, north Norwegian Caledonides, have yielded the following ranges of Nd depleted-mantle model ages: orthogneiss 2.8 Ga; paragneisses 1.2-1.8 Ga; and Soroy Succession metasediments 1.2-2.0 Ga. The presence in the Complex of sedimentary detritus derived from young (< 1.3 Ga) crust indicates that sedimentation and deformation of these rocks are probably younger than 1.3 Ga. Crust as young as 1.3 Ga seems to be absent from north Baltica, implying that at least some of the Kalak Nappe Complex sediments were derived from sources outside the craton.