IODP

doi:10.14379/iodp.sp.352.2013

Site summaries (continued)

Proposed Site BON-4A

Priority: Alternate
Position: 28°25.46′N, 142°36.12′E
Water depth (m): 3130
Target drilling depth (mbsf): 850 (100 m sediment, 750 m basement)
Approved maximum penetration (mbsf): 1350 (pending EPSP approval)
Survey coverage: Line IBr11n CDP 7817
• Track map (Fig. AF1)
• Seismic profiles (Figs. AF2, AF4, AF5, AF7)
Objective: Characterize upper volcanic stratigraphy at Bonin fore arc to investigate subduction initiation processes and test supra-subduction zone ophiolite models
Drilling, coring, and downhole measurements program: • Hole A: jet-in test
• Hole B: APC/XCB to basement (100 mbsf)
• Hole C: reentry system (16 and 10-3/4 inch casing to 105 mbsf)
• Hole C: drill without recovery to 110 mbsf, RCB from 110 to 850 mbsf
• FlexIT core orientation measurements
• Wireline logging (triple combo, FMS-sonic)
Nature of rock anticipated: Pelagic carbonate with thin ash layers, boninite, and basaltic lavas