Site summaries (continued)

Site BOW-15A (Bowers Ridge): middle Pliocene

54°49.7′N, 176°55.0′E (WGS 84)
Water depth (m)
Target drilling depth (mbsf):
Approved maximum penetration (mbsf):
Previous drilling in area:
DSDP Site 188
Site location and depth of penetration approved by EPSP in December 2005
Survey coverage (track map, seismic profile); sediment cores:
R/V Hakuhou-maru Cruise KH99-3 Leg 3 (1999):
• Track map (Figs. AF17, AF18)
• MCS profile: Shotpoint 410 on Line Stk4-1 (N–S) (Figs. AF19, AF20)
• Crossing Line Stk4-3 (W–E) (Figs. AF21, AF22)
• Subbottom profile, 3.5 kHz: Line Stk4-1 (W–E) (Fig. AF23)
• Swath bathymetry: Line Stk4-1 (N–S) and Stk4-3 (W–E) (Fig. AF24)
• Piston core (9 m)
Objective (see text for complete details):
Provide high-resolution records from the shallowest part of vertical depth transect in the south of the Bering Sea; will be used to evaluate vertical water mass gradients when compared to other sites.
Useful in monitoring the exchange of North Pacific and Bering Sea water at shallower depths from the middle Pliocene through the Pleistocene.
Reconstruct Pliocene–Pleistocene high-resolution paleoceanography and investigate the Bering/Arctic Gateway history.
Drilling/coring program:
Triple APC in Holes A, B, and C: APC with core orientation to 165 mbsf and in Hole D to 25 mbsf
Temperature measurements: 3 APCT-3
Downhole logging program:
No wire-logging currently planned for this site because of shallow penetration
Anticipated lithology:
Hemipelagic silty clay with siliceous and calcareous microfossils

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