Site summaries (continued)

Site BOW-14B (Bowers Ridge): upper Miocene

54°02.0′N, 179°00.5′E (WGS 84)
Water depth (m)
Target drilling depth (mbsf):
Approved maximum penetration (mbsf):
Previous drilling in area:
DSDP Site 188
Relocated from Site BOW-14A to Shotpoint 670 on Line Stk5-1 during Cruise KH99-3, 1999. Approved depth of penetration was reduced to 600 mbsf because of concerns about penetrating the strong amplitude event near the original proposed depth of penetration (EPSP December 2005).
Survey coverage (track map, seismic profile); sediment cores:
R/V Hakuhou-maru Cruise KH99-3 Leg 3 (1999):
• Track map (Figs. AF9, AF10)
• Swath bathymetry: Line Stk5-1 (W–E) and Stk5-5 (S–N) (Fig. AF11)
• Subbottom profile, 3.5 kHz: Line Stk5-1 (W–E), Line Stk5-5 (S–N), (Fig. AF12)
• MCS profile: Line Stk5-1 (W–E) (Figs. AF13, AF14)
• Crossing Line Stk5-5 (S–N), Shotpoint 2488 (Figs. AF15, AF16)
• Multiple cores (30 m)
Objective (see text for complete details):
Provide high-resolution records from the deepest part of vertical depth transect in the south Bering Sea; will be used to evaluate vertical water mass gradients when compared to other sites.
Monitor exchange of North Pacific and Bering Sea water from the upper Miocene through the Pleistocene.
Drilling/coring program:
Triple APC to refusal, and XCB to 555 mbsf:
• Holes A, B, and C: APC with core orientation to refusal (~200 mbsf)
• Hole C: XCB to ~555 mbsf; logging
Temperature measurements: 3 APCT-3, 2 DVTP if required
Downhole logging program:
Wireline logging: triple combo, FMS-sonic
Anticipated lithology:
Hemipelagic silty clay with siliceous microfossils

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