ALKALINE ROCKS IN GREENLAND
Mesozoic-Tertiary dyke swarms in West Greenland

Lotte Melchior Larsen

Along the coast of West Greenland occur sporadic swarms of small-volume alkaline dykes that have been dated at 55-200 Ma. Their distribution, orientation, and compositions, are of relevance for the history of continental stretching, break-up, and formation of the Labrador Sea and the Davis Strait in the Mesozoic–Tertiary. This very complicated history is important for the assessment of the petroleum potential in West Greenland. The dykes are easily overlooked and are typically found in connection with other activities.
A collection of such rocks, and analyses of them, has been built up by GEUS over the years, the most recent addition being samples from the field work in 2004. The project is also relevant for the ongoing work on igneous samples from dredges offshore West Greenland,

Publication
Larsen, L.M. & Rex, D.C. 1992: A review of the 2500 Ma span of alkaline-ultramafic, potassic and carbonatitic magmatism in West Greenland. Lithos 28, 367–402.

Larsen, L. M., Rex, D. C., Watt, W. S. & Guise, P. G. 1999: 40Ar–39Ar dating of alkali basaltic dykes along the south-west coast of Greenland: Cretaceous and Tertiary igneous activity along the eastern margin of the Labrador Sea. Geology of Greenland Survey Bulletin 184, 19–29.