The Wolf Cave Gabbro – alkaline olivine basaltic magmatism in Jersey, Channel Islands

An 8m thick coarse-grained olivine dolerite dyke, with well-developed chilled margins, trending NNE-SSW and occupying a steep-sided cove on the north Jersey coast, may show evidence for some flow differentiation. Texturally, the dyke is remarkable for the pronounced poikilitic relationship between the constituent mafic minerals. The textural and chemical relationships between the mineral phases are discussed. Rock and mineral chemistry indicate that magmatism was of alkaline-olivine basaltic type, contrasting markedly with most other hypabyssal basic magmatism in the island. A link with  the prominent swarm of N-S basic dykes found on the adjacent North Brittany coast is postulated.