Orientations of dikes within the sheeted dike complex of the Troodos ophiolite reveal primary spreading structure produced at a complex ridge/transform intersection. Three structural grabens are defined by listric and planar normal faults and rotated dikes that dip symmetrically toward graben axes. Faults flatten at depth into a detachment within the upper parts of the plutonic complex. Large exhalative massive sulfide deposits occur within the pillow sections of two of the grabens and appear to be associated with underlying altered and mineralized normal fault zones that channeled hydrothermal fluids. We suggest that the grabens are fossil axial valleys produced by successive eastward jumps of an approximately north-trending (present coordinates), slow-spreading ridge crest. A simple model for ridge migration indicates eastward jumps of 8–13 km; changes in ridge orientation are suggested by changes in trends of dikes and graben axes. Comparison of the pattern of dikes near the Arakapas fault zone with the structure of active ridge/transform intersections suggests that the fault is a right-offset (sinistral) transform, in contrast to earlier models in which a ridge to the west of the exposed Troodos complex was proposed.
- Geological Society of America