Proposed Site SubSAT-3B is located on the northern Meteor Rise in 2008 m water depth, approximately 34 nmi to the northwest of Site 704. During ODP Leg 114, a 500-m-thick Neogene sequence was recovered from Site 704, but significant core disturbance (e.g., missing and double cored sections) is evident in Holes 704A and B during some intervals, and the core breaks occur at almost the same depth in the two holes, making it impossible to retrieve missing or disturbed sections in the companion hole. Site SubSAT-3B is expected to provide an identical record to Site 704 in terms of age, sedimentation rate, and lithology, but will be far superior in terms of coring disturbance, gaps, and turbidites. Sediments at Site SubSAT-3B should be composed of alternating calcareous and siliceous ooze during the Pleistocene, grading into dominantly calcareous ooze with a significant biosiliceous component during the Pliocene. Average sedimentation rates are expected to be 3 cm per tens of years during the Brunhes Chron, increasing to an average of 7 cm per tens of years during the Matuyama Chron, and decreasing again to 2 cm per tens of years during the Gauss and Gilbert Chrons. Site SubSAT-3B is approved to be cored by triple APC in the upper 200 m. Because 672 m of sediment was drilled in Hole 704B to the early Oligocene, recovery beyond the depth of APC penetration (>200 m) at Site SubSAT-3B is not warranted. Site SubSAT-3B should penetrate to the early Pliocene (~4.0 Ma) according to the section recovered at Site 704. Specific objectives at Site SubSAT-3B include the recovery of a continuous composite section of the Pliocene-Pleistocene ~2.5°N of the present-day position of the PFZ in 2008 m of water.
Site SubSAT-4B is located to the south of the Davis Seamounts in a region where high sedimentation rates occur, and is south of the present-day position of the Polar Front of the ACC in a water depth of 3661 m (Fig. 1). This site is located at 52°S between Sites TSO-6A and TSO-7C and serves as a good backup to either of these sites in the event that weather or icebergs prevent us from occupying either of them. Site SubSAT-4B is approved to be drilled using triple APC to 200 m, XCB to 400 m, and RCB to 800 m to recover late Cenozoic biosiliceous and calcareous sediments at high resolution south of the present-day position of the PFZ. The objectives are essentially the same as those outlined for Sites TSO-6A and TSO-7C.
Site SubSAT-4C has been selected as an alternate to Site SubSAT-4B in the unlikely event that an iceberg prevents occupation of the primary site. The objectives and drilling strategy at SubSAT-4C are identical to those described for SubSAT-4B.
Site TSO-6B is an alternate to Site TSO-6A in the unlikely event that an iceberg prevents occupation of the primary site. The objectives and drilling strategy at TSO-6B are identical to those described for TSO-6A.
Site TSO-7B is an alternate to Site TSO-7C in the unlikely event that an iceberg prevents occupation of the primary site. The objectives and drilling strategy at TSO-7B are identical to those described for TSO-7C.
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