Abstract
The recently redefined Upper Pillow Lava suite of the Troodos ophiolite in Cyprus is composed of a series of related rock types: ultrabasic rocks, komatiites, olivine basalts and aphyric basalts, derived from a highly depleted primary melt by dominant olivine fractionation. Differentiation within high-level magma chambers involving approximately 25% olivine fractionation, and subsequent tapping of the resultant magma types explains the field relationships observed.