DRILLING STRATEGY
The five high priority sites summarized in Table 2 and shown in Figure 4 are planned to be drilled in an arc from west to east (i.e., from the Indian to Pacific Oceans).
North-South Transect
Proposed Sites WT-1A, ETP-2A, WSTR-1B, WSTR-2A, and STR-2A will extend from well north
of the Subtropical Convergence to almost as far south as the present-day Polar Front. This transect
will provide constraints on glacial-interglacial meridional oscillations in the Southern Ocean surface
waters. The sites are near or above the regional lysocline and should provide continuous Neogene
stable isotope and foraminiferal records. The transect will also aid the integration of cold-water
siliceous biostratigraphy with temperate carbonate microfossil biostratigraphy.
Site ETP-2A has the additional advantage of being in position to monitor paleoceanographic changes at the confluence of the East Australia Current and the Subtropical Convergence, one of the areas of Western Boundary Current heat transport into the Southern Ocean.
East-West Transect
Proposed Sites WT-1A, WSTR-1B, WSTR-2A, and ETP-2A will provide information on the
Cenozoic reduction of microfossil provinciality between the Indian and Pacific Oceans as the
barrier of the STR diminished with time.
Coring
Most of the sites will be triple cored with the advanced hydraulic piston corer/extended core barrel
(APC/XCB) systems to about 200 m (refusal) in the Neogene. XCB coring will continue to ~500 m
in the first APC hole. The remainder of each site will be cored in a fourth hole with the rotary core
barrel (RCB) after washing to within 10 m of the XCB depth. Reentry with a free-fall funnel (mini
cone) may be unavoidable at Sites WT-1A and STR-2A.