Sheeted dyke complex

A sheeted dyke complex or sheeted dike complex is a normal component of an ophiolite, a piece of oceanic crust that has been emplaced within a sequence of continental rocks. In the original formation environment below the sea floor the dykes acted as feeders for the overlying sequence of extrusive rocks, typically pillow lavas forming a layer of the oceanic crust. As each injection of a dyke represents one increment of seafloor spreading, each dyke was normally intruded into earlier dykes. The dykes are typically dolerites but plagiogranites (trondhjemites) often form a significant part of the complex.