A wide variety of geological evidence supports the contention that the Troodos massif, Cyprus is a fragment of Mesozoic sea-floor created at a constructive plate margin. Here the geology of an east-west striking fault zone in the southern part of the massif, the Arakapas Fault Belt (APB), is investigated and evidence is presented which supports its interpretation as a fossil transform fault. The Arakapas Fault Belt area had a trough-like morphology during constructive margin processes. Rocks within this area have been intensely brecciated by transcurrent faulting and the resultant basement, which formed a rugged topography, is overlain by later lava flows and erosional sediments deposited by a variety of sub-aqueous mass transport processes (slides, slurries, turbidity currents). All these rocks were later intruded by serpentinite and cut by a closely related system of normal and reverse east-west faults. The petrography and geochemistry of the APB area basalts is investigated and compared to those from the "normal spreading axis" northern part of the massif. The metamorphic mineral assemblage differs and a greater proportion of primative basalt types are present than in the north. Magmas have evolved along two fractionation paths, and this is interpreted as a consequence of variations in primary magma compositions as determined by the degree of partial melting within the mantle.