A metamorphosed basic dyke swarm in the vicinity of Sarqarigsup nunâ (Ravns Storø area), Fiskenæsset, southern West Greenland

Abstract

Ancient dyke swarms have been used successfully as time markers throughout the Archaean of West Greenland, particularly in subdividing the early Archaean in the Godthåb region (McGregor, 1973). This paper describes a swarm of metamorphosed basic dykes which cut across the lithologicallayering and an early tectonic fabric in the Ravns Storø group of metavo1canic and plutonic rocks. Previously only sporadic occurrences of metamorphosed basic dykes have been noted in the Fiskenæsset region. The Sarqarigsup nuna swarm may thus have a significant part to play in the division of the events which have taken place in the area from the Frederikshåbs Isblink to Bjørnesund and perhaps even further north.