Petrochemistry and origin of the Raudhamaren Ultramafites, Jotunheimen.

Abstract

The ultramafites show gradual petrochemical variation and Mg\/Feratios indicative of crystallisation differentiation from stratiformtype mafic magma series. The country rocks with which they are inprimary association, however, have a calc-alkaline trend of evolution,more indicative of affiliation with th alpine type. The ultramafitesare essentially spinel peridotites thought to have formed in a dryenvironment by diapiric upwelling during the basaltic (gabbroic)evolution of the Upper Mantle.