From ophiolites to oceanic crust: Sheeted dike complexes and seafloor spreading

Persistent, coordinated plate separation and dike intrusion generate sheeted dike complexes in oceanic crust at mid-ocean ridge spreading centers and other magmatic rifts. Although sheeted dike complexes were first described in ophiolite complexes, investigations of dikes, dike intrusion events and sheeted dike complexes in the oceanic crust have provided new constraints on how sheeted dike complexes form and their significance for the accretion of oceanic crust at spreading centers. Despite the general appearance of a monotonous array of side-by-side intrusions, details of sheeted dike complexes hold important keys to understanding the fundamentals of the tectonics, magma plumbing networks and hydrothermal/biological systems at mid-ocean ridges. In situ investigations of sheeted dikes and related upper crustal units in seafloor exposures provide fundamental observations that have implications for deformation during spreading, the reconstruction of ophiolite complexes, and the restoration of ophiolite structures to spreading center reference frames.