Geology of the Fairway and New Caledonia Basins in the Tasman Sea: Sediment, Pore Water, Diapirs and Bottom Simulating Reflectors ( Franklin Cruise FR9/01 and Geoscience Australia Survey 232)

The Lord Howe Rise and Norfolk Ridge are major north-south structural highs that are separated by the Fairway Basin and the New Caledonia Basin. The Fairway Basin is the shallower of the two basins and is generally in water less than 3000 m deep. The New Caledonia Basin lies further east in water generally deeper than 3600 m. In the area studied on the Franklin research cruise FR9/01, the two basins are about 300 km wide and 900 km long. About 2800 km of 24 channel seismic profiles provided vital information in a very poorly known region. In the Central Fairway Basin in the north, two new east-west cross-sections found more diapirs, and evidence of a bottom-simulating reflector (BSR) indicating the presence of gas hydrates, and young faulting. They increased our knowledge of a part of the basin known to have petroleum potential.

In the south, there are six east-west multichannel seismic cross-sections in an area of Australian jurisdiction, where there were none. These seismic profiles show that the deep water depression south of 26.20 S is an extension of the Fairway Basin. It is limited by the Lord Howe Rise to the west and the northern extension of the West Norfolk Ridge to the east, and is roughly 700 km long and 100 km wide: an area of 70,000 km. The basin contains sediments more than 2 seconds thick in places, shallow and deep diapirs (especially north of 29 S), and a BSR in some regions. Water depths are 1200 m to 3600 m. Clearly, the South Fairway Basin has some petroleum potential, although the apparent maximum thickness of sediment (