Age constraints on Atlantic evolution: timing of magmatic activity along the E Greenland continental margin

Abstract

Summary The results of a comprehensive K-Ar investigation of 130 petrographically selected rock and mineral specimens from the E Greenland Tertiary Igenous Province are reported. The new age data refine the chronology of this region. They suggest the following conclusions: (1) the lavas were extruded between 54 and 57 Ma; (2) the pre-flexure dyke swarm was intruded between 51 and 53 Ma; (3) the postflexure dyke swarm was intruded between 49 and 51 Ma; and (4) plutonic activity occurred at 50 Ma (Kangerdlugssuaq, Kraemers Ø, Lilloise, etc.), 42–45 Ma (Borgtinderne, Kap Deichman, etc.), 36 Ma (Kialineq), 38 and 28 Ma (Kong Oscars Fjord, Myggbukta).