Priority:
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Primary:
- Chikyu Expedition 314 (LWD)
- Chikyu Expedition 316 (Thrust Faults)
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Position:
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33°1.635′N, 136°47.639′E
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Water depth (m)
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3832
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Target drilling depth (mbsf):
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950 sediment (Stage 1)
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Approved maximum penetration (mbsf):
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1800; approved by CDEX and TAMU safety panels based on EPSP Jan 2007 recommendation
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Survey coverage:
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CDEX 2006 3-D MCS survey; extensive survey data outlined in Proposal 603A-Full2 (www.iodp.org/nantroseize-downloads):
- Track map (Fig. AF15)
- CDEX/IFREE 3-D inline (Fig. AF16)
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Objective
(see text for full details):
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Penetrate the toe of the Nankai accretionary prism to:
- Characterize incoming sedimentary sequence (lithologic, hydrologic, thermal, geotechnical, geochemical properties)
- Document early phases of deformation
- Verify location of frontal décollement
Although penetration to basement is desirable, a more important goal is to sample as much of the lower Shikoku Basin as possible.
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Drilling, coring, and downhole measurement program:
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Chikyu Expedition 314 (LWD):
- Pilot hole - MWD
- Hole A - MWD/LWD to TD
Chikyu Expedition 316 (Thrust Faults):
Hole B (if TD cannot be achieved, start Hole C):
- APC/XCB
- Core orientation
- Downhole temperature measurements
Hole C:
- Drill without coring to depth of Hole B
- RCB core to TD
- Wireline logging as contingency if Expedition 314 LWD is not accomplished
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Anticipated lithology:
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0–20 mbsf: hemipelagics and volcanic ash
20–600 mbsf: uplifted trench turbidites
~600 mbsf: frontal thrust
600–1100 mbsf: trench wedge turbidites
1100–1400 mbsf: upper Shikoku Basin hemipelagics and volcanic ash
1400–2800 mbsf: lower Shikoku Basin hemipelagics and turbidites
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