Oceanic inside corner detachments of the Limassol Forest area, Troodos ophiolite, Cyprus

Flat-lying extensional detachment faults have been imaged in the inside cor ner regions of ridge-transform intersections on the Mid-Atlantic Ridge, Exp osed detachment surfaces are 10 km or more across, and are corrugated in th e direction of spreading, as are continental detachments. Beneath the detac hments lie core complexes of peridotite and gabbro; these are overlain by b locks of crustal material. We argue here that similar detachments are an es sential component of the Limassol Forest area of the Troodos ophiolite in C yprus, which ties south of the Arakapas Fault zone, previously recognized a s a palaeo-trans form fault, and here interpreted as a transform fault that evolved into a fracture zone. In the Limassol Forest, core complexes of ma ntle peridotite can be shown to have been exposed at the sea floor, or to h ave been covered by overlapping crustal blocks, separated from the peridoti te core and from each other by low-angle extensional faults. The extension can be shown to have occurred shortly after crustal construction, and the a lready extended terrain was then intruded by swarms of dykes and plutons. W e interpret these relations as arising when crust is constructed in an insi de corner area. extended by detachment faulting, deformed further during sl ip along the transform, and then intruded by new magma as it passes the sec ond spreading centre. The structurally deeper parts of the crustal blocks t hat overlie the detachment lie broadly towards the west, indicating that th e spreading axis lay in that direction. The ophiolite north of the transfor m is much less extended, and we interpret this as a section of outside corn er crust. In this interpretation, the Troodos ophiolite formed to the east (in its current orientation) of a ridge-transform-ridge intersection, in wh ich the transform had a dextral offset and sinistral slip. The part of the ophiolite that forms the Limassol Forest was produced at the western inside corner, and spread eastwards until it passed the second spreading axis, at which point the ophiolite north of the Arakapas Fault was created and weld ed to the Limassol Forest when the transform became a fracture zone.