Structural Controls on the Location and Form of the Vourinos Chromite Deposits

The development of new methods of exploration for chromitite requires an understanding of the most crucial elements involved in the concentration and preservation of the ore deposits. Following their formation at constructive plate margins, chromite deposits are subject to deformation, within the upper mantle, as the enclosing lithosphere spreads away from the ridge axis, and during decoupling from the oceanic plate under a steadily failling P-T regime. The construction of a comprehensive emplacement model for the Vourinos complex shows that emplacement fabrics are prevalent throughout the chromite-bearing mantle sequence. Detailed studies of two key localities on Vourinos indicate that both mantle and emplacement structures are preserved within the chromite deposits, although their respective role in the present form and distribution of the chromite deposits differs between the two localities. This study suggests a new exploration strategy for the Vourinos complex which relies on more expansive structural models than previously applied in ophiolitic terrain. These models evaluate each phase of deformation and address its effect commencing with post-emplacement structures and working backwards to the earliest ridge tectonics. They are then modified to suite the style of deformation which is predominant in a particular mineralized area.