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Tiarei inner ridge: Site M00231

Expedition 310 Scientists2


Hole M0023A

From 0000 h on 10 November 2005, Seacore’s drilling and reentry template (DART) was raised to the moonpool after abandoning coring in Hole M0022A. The DP Hunter moved to a new area over a drowned reef to conduct an echo sounder survey, ~100 m southwest of proposed Site TAH-02A 4. From 0200 h on 10 November, 9 echo sounder traverses (~110 m long) were made over the drowned reef pinnacle, from which a site for Hole M0023A was chosen in 67 m water depth. After a short camera survey, coring operations in Hole M0023A started at 0635 h on 10 November and ended at 2245 h that day after reaching a total depth (TD) of 31.36 meters below seafloor (mbsf) with a total recovery of 77.20%.

Hole M0023B

After raising the DART a short distance from the seabed, the DP Hunter was positioned above Hole M0023B, 5 m southwest of the previous hole in 67 m water depth. Coring operations in Hole M0023B began at 0120 h on 11 November 2005 and ended at 1540 h that day at a TD of 31.12 mbsf with a total recovery of 67.90%. The coring operation proceeded smoothly, with excellent core recovery in long core runs in often very porous formation.

Prior to logging, the drill pipe was pulled and the hole flushed for 30 min before the drill pipe was run-in with a casing shoe to ~6 mbsf. Logging commenced at 1700 h on 11 November. Initially, the tools would not pass below the casing shoe, even after the chisel tool was worked in the hole. The casing shoe was run to the base of the hole and back before the chisel tool was deployed to check that the casing shoe was clear. Logging operations restarted at 2000 h, with the tools reaching a maximum depth of 28.5 mbsf. A dynamic positioning (DP) malfunction caused the vessel to move off location during the logging, but the situation was recovered and the hole and equipment remained intact. The optical and acoustic logs preview indicated that there were many cavities in the formation. Logging finished in Hole M0023B at 0310 h on 12 November.

1 Expedition 310 Scientists, 2007. Tiarei inner ridge: Site M0023. In Camoin, G.F., Iryu, Y., McInroy, D.B., and the Expedition 310 Scientists. Proc. IODP, 310: Washington, DC (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/​iodp.proc.310.107.2007

2 Expedition 310 Scientists’ addresses.

Publication: 4 March 2007
MS 310-107