IODP

doi:10.2204/iodp.sp.320321.2008

Site summaries

Site PEAT-1C (early Eocene Equator)
Priority:
Primary for Expedition 320, alternate for Expedition 321
Position:
12°04.089N, 142°09.698W (WGS-84)
Water depth (m):
5132 (6.842 s TWT)
Target drilling depth (mbsf):
187 then tag basement
Approved maximum penetration (mbsf):
250 (approved by TAMU safety panel based on EPSP June 2006 recommendation)
Survey coverage
(track map; seismic profile):
Roger Revelle (7 April 2006; ~6 kt):
• Simrad EM-120 multibeam system
• Knudsen 320B subbottom profiler
• Dual 150 c.i. GI seismic sources
• Scripps 48-channel Geometrics GeoEel
Piston core: 11.3 m (RR0603-11JC)
Primary seismic line: PEAT-1 Line 8 (Figs. F11, F12, F13) (see also report to the EPSP panel, available at eprints.soton.ac.uk/45921)
Objectives:
Located on ~53 Ma crust to Intercept the 53–50 Ma interval in basal carbonate sediments above the shallow early Eocene CCD (4200–4300 m) and to obtain and characterize continuous sediment archive to basement.
Drilling program:
Preferred:
• Holes A, B, C: APC with core orientation to refusal; XCB to basement; logging in Hole A
Minimum:
• Hole A: APC/XCB to basement
• Holes B and C: wash to 100 m; APC/XCB to basement.
Downhole measurement program (low priority at this site):
• Wireline logging: triple combo, FMS-sonic, possibly check shot
• Temperature measurements: 3 APCT-3, 2 DVTP
Nature of rock anticipated:
Clay, radiolarian ooze, nannofossil ooze/chalk, possibility of chert strings, hydrothermically altered ridge basalt