Uruski, C.I. 1992 Sedimentary basins and structure of Cook Strait. Lower Hutt: Institute of Geological & Nuclear Sciences. Institute of Geological & Nuclear Sciences science report 92/03. 18 p.
Abstract: Cook Strait separates North Island from South Island, New Zealand. It occupies part of the boundary zone where the westwards-dipping, oblique subduction of the Pacific Plate changes to the eastwards-dipping transform margin of the Alpine Fault. It is a key area where knowledge of its geology is fundamental to the understanding of the evolution of New Zealand. However, little useful seismic data exists in the area. The only multi-channel data available was shot by oil exploration companies in the late 1960s and early 1970s. As a result, Cook Strait is a bone of contention for all geologists working in the region and it promises to remain so until it receives the attention of a modem seismic vessel. The old data show that three thick sedimentary basins are located within Cook Strait; the Wairau, Wairarapa and Clarence Basins. Gravity anomalies are mapped over each of these basins. Their three-dimensional geometry strongly suggests that they originated as half-graben rift basins and two of them, the Wairau and Wairarapa basins were before re-activated as pull-apart basins. The Wairau Basin has recently become compressional while the Wairarapa Basin has remained tensional. The Clarence Basin also started as a tensional basin and its history is less clear. It seems to have developed as part of a passive margin or shelf sequence and later became strongly compressional with no hint of strike-slip motion associated with it. At present, dating of the events is very tentative. The initial rift development may have been of Late Cretaceous age and strike-slip movements may have started in the Early Miocene, suggesting that the pull-apart basins are mainly of Miocene age.
