|
Ophiolites and Oceanic Crust |
Institute of Oceanographic Sciences, Brook Road, Wormley, Godalming, Surrey GU8 5UB, UK
A major strike-slip fault zone, at least 5 km in width, trends E-W along the southern margin of the Troodos ophiolite. It is an ocean-floor feature, overlain by undeformed pelagic sediments, and is orientated perpendicular to the mean strike of the sheeted dyke complex of the main ophiolite massif. It has long been recognized as probably the foremost example of a fossil transform fault within an ophiolite.
We present here detailed description of the structure and tectonic evolution of this so-called ‘Southern Troodos Transform Fault Zone’ (STTFZ), based upon 1:5000 scale mapping of the whole of the southern margin of the Troodos ophiolite. The styles of strike-slip deformation at all levels of the oceanic crust and upper mantle, and the variations in deformation style with time, are documented and the role of vertical-axis rotations within and adjacent to the transform zone is discussed. Evidence for the kinematics of deformation is reviewed; previous studies have been unable to agree even on such fundamentals as the sense of slip of the STTFZ. In an attempt to resolve the controversy we have made a systematic re-examination of the evidence for the direction of motion along the transform, supplemented by new field observations where necessary. We conclude that, although there is incontrovertible evidence for both sinistral and dextral shear along the STTFZ whilst it was in an oceanic environment, the overwhelming indications are for dextral slip. We show that sinistral indicators are restricted to a few small mylonite shears that are probably related to local geometrical complexities associated with the intrusion of gabbroic plutons into the transform; there is no need to invoke wholesale reversal of slip sense along the STTFZ as a whole.
This article has been cited by other articles:
 |
|
 |
|
  Z. Garfunkel Neotethyan ophiolites: formation and obduction within the life cycle of the host basins Geological Society, London, Special Publications, 2006; 260: 301 - 326. [Abstract] [PDF]
|
|
|
|
|
|
A. Morris, M. W. Anderson, J. Inwood, and A. H. F. Robertson Palaeomagnetic insights into the evolution of Neotethyan oceanic crust in the eastern Mediterranean Geological Society, London, Special Publications, 2006; 260: 351 - 372. [Abstract] [PDF]
|
|
|
|
|
|
M. F. J. Flower and Y. Dilek Arc-trench rollback and forearc accretion: 1. A collision-induced mantle flow model for Tethyan ophiolites Geological Society, London, Special Publications, 2003; 218: 21 - 41. [Abstract] [PDF]
|
|
|
|
|
|
Y. Dilek and M. F. J. Flower Arc-trench rollback and forearc accretion: 2. A model template for ophiolites in Albania, Cyprus, and Oman Geological Society, London, Special Publications, 2003; 218: 43 - 68. [Abstract] [PDF]
|
|
