Low Alkali, High Calcium Olivine Tholeiite Lavas from the Isle of Skye, Scotland

The recognition in Skye of olivine tholeiite lava flows, withlow alkali (1?7–1?9 per cent Na₂O,0?04–0?14 percent K₂O) and high calcium (12?7 per cent CaO), is reported.An account of their mineralogy and petrology, seven major elementanalyses, some trace element data, and the results of one atmospheremelting experiments are presented. These lavas, quite distinctfrom the plateau lavas in Skye, are postulated as representingthe early stages of a central cone volcano in S.W. Skye andthought to be closely related to the parental magmas of theCuillins layered basic intrusion complex.