Revdal

The Revdal area of Scoresby Land, Semersooq, Greenland hosts a steep valley intruded by several dykes. These structures are subvertical, thin (0.1-0.5 m), striking between 116° and 154° N and intruding the conglomerates of the Huledal Formation, the evaporites of the Revdal Member of the Karstryggen Formation, and Early Permian continental sandstones. These dykes terminate at the contact with the limestone of the Karstryggen and Wegener Halvø Formations, with clasts of dyke rocks found within conglomerates ~5 m above the contact of the dykes and limestone, formed via hydraulic fracturing of wet sediment. Unexplained occurrences of dyke clasts occur at higher levels above the contact. Dyke rocks are alkaline lamprophyres, described as monchiquites, alnöitic monchiquites, and fourchites, with the main phenocryst being clinopyroxene. Pseudomorphed olivine is found only in the monchiquites and alnöitic monchiquites, and biotite or phlogopite phenocrysts restricted to alnöitic monchiquites. Whole rock data and CIPW norms can be found in Larsen et al. (1990).