The distribution of Arenig graptolite faunas and zones of differing metamorphic fades help to establish a polyphase imbrication history for the complex. A further complication is introduced by the presence within the imbricate stack of lava sequences of comparable age but with contrasting geochemical signatures of island-arc and oceanic island basalts, and oceanic island sequences of markedly different Arenig ages. Strike-slip mechanisms appear the most likely means of introducing such a disparate assortment of elements into the Ballantrae complex and an origin in a continental margin transform zone is preferred.