Structural geology of Suva Peninsula and Harbour and its implications for the Neogene tectonics of Fiji

Evidence for four generations of deformation has been preserved in the Early Pliocene Suva Marl of solltheast Viti Levu, Fiji. Initially, an intense, parallel jointing formed in discrete north‐south zones on the hinges of faulted monoclinal flexures. Later, large monocline‐bounded grabens on a northeast trend were superposed on the north‐south zones. Subsequently, a third generation of deformation occurred with the development of northwest‐trending faults displaying elements of both dip and strike‐slip displacement In a late‐stage deformational event, kink‐like folds distorted the intense jointing at widely scattered localities. The local structures indicate that extension has been the predominant mode of deformation during the tectonic history of southeast Viti Levu, and there is no evidence of strike‐slip movements. It is proposed that the local structures in Suva Harbour can be correlated with the regional megastructures. The northeast structures are seen as extensions of the Hunter Fracture Zone. The northwest structures are correlated with transcurrent faults that offset the Hunter Fracture Zone. By implication, strike‐slip movement is unlikely to have occurred, at least in this area, on the Hunter Fracture Zone, and current activity in southeast Viti Levu is probably due to northwest faulting rather than transcurrent displacement on the Hunter Fracture Zone.