Mafic-dominated volcanogenic sulphide deposits in the Troodos ophiolite, Cyprus Part 1 - The deposits of the Solea graben

The Solea graben in the Troodos ophiolite of Cyprus is host to some of the largest and richest cupriferous sulphide deposits on the island. The graben is oriented in a northwesterly direction and defined by similarly oriented dykes and faults. The deposits within the graben display a variety of characteristics which reflect their mode of genesis. They include deposits displaying classic exhalative genesis, as well as others which formed at some depth below the seafloor, or by fluids which travelled away from their source to deposit sulphide on the surface of the ocean floor. A special case is the Phoenix deposit which is the result of supergene enrichment from the weathering of massive sulphide. A strong control of ore deposition is evident for some of the deposits by a major structure interpreted as an oceanic detachment fault. Other deposits are localised at the intersection between axial structures and transfer faults. However, in all cases, an underlying heat source appears to have played a major role in ore deposition. The location of the deposits at the top of the volcanic sequence is consistent with an off-axis setting.