Results of investigation of Tertiary volcanic breccia south of Niaqornat, Nûgssuaq, West Greenland, 1971

Abstract

On the Nûgssuaq peninsula, south of Niaqornat village and east from the northerly extension of the Itivdle valley, there lies an area in which Cretaceous and Danian sediments are overlain by igneous rocks. These rocks in the main are highly altered, ultrabasic breccias. Further east basalt flows cap the high ridges. The area visited was the high ridge between the valley Tunorssuaq and the north coast, east and west of Niaqornat village. In particular considerable attention was given to the area described by Arnold Heim (1910, p. 209) 4 km south-west of Niaqornat village. Heim was the first to discover these rocks and classified them as intrusive mainly because of the graphitisation of some of the shales nearby. This idea was continued by Rosenkrantz (in Birkelund, 1965, plate 49), Rosenkrantz & Pulvertaft (1969, p. 892) and Henderson (1969 a, p. 20; 1969 b, p. 25).