Trace-element abundances of the Holterkollen pluton complex, Oslo Area, Norway

The behaviour of Rb, Cs, Ba, Sr, U, Th, Zr, Hf, Ta, Sc and Y in the Holterkollen plutonic complex as a function of increasing differentation index in the granite-quartz porphyry series and in the akerite-syenite-ekerite series is found to be of great geochemical importance. The present data indicate that the Holterkollen granites probably belong to two different types: differentiated and highly differentiated granites. Thirty-seven samples representing the different rock types of the pluton were analysed for Rb, Cs, Ba, Sr, U, Th, Hf, Ta, Sc and Co by combined neutron activation and X-ray fluorescence methods. Zr and Y were spectrochemically determined. In an attempt to clarify and confirm the genetic sequence of the various units of the pluton, critical trace-element distributions are presented and discussed in this paper. (Auth.)