The Sulugssut intrusive complex: a new Tertiary alkaline centre in East Greenland

Abstract

The Sulugssut intrusive complex, discovered in 1986, lies between the glaciers of K. J. V. Steenstrup Søndre Bræ and K. J. V. Steenstrup Nordre Bræ at 66° 30´N. It has an approximate diameter of 5 km and consists of dense dyke swarms and a plutonic core in which tinguaites and ijolites appear to predominate. It is of particular interest on three main counts: (1) it represents the most southerly in the line of Tertiary igneous centres which stretches over 1000 km to the north, (2) its petrographic character, although resembling the Gardiner intrusion to the north, is unique in East Greenland, and (3) it is located dose to the coast confounding earlier ideas that highly undersaturated magmas occur only inland.