Site summaries (continued)

Proposed Site PEAT-5D (alternate to Site PEAT-5C)

Alternate to Site PEAT-5C
07°42.069’N, 128°06.568’W (WGS-84)
Water depth (m):
4400 (5.867 s TWT)
Target drilling depth (mbsf):
296 then tag basement
Approved maximum penetration (mbsf):
330 (approved by TAMU safety panel based on EPSP May–June 2007 recommendation)
Survey coverage
(track map; seismic profile):
Roger Revelle (31 March 2006):
• Simrad EM-120 multibeam system
• Knudsen 320B subbottom profiler
• Dual 150 c.i. GI seismic sources
• 4-channel streamer
Piston core: 11.1 m (RR0603-07JC)
Primary seismic line: PEAT-5 Line 6
Crossline: PEAT-5 Line 3 (Figs. F24, F25, F26) (see also report to the EPSP panel, available at
Site PEAT-5D (alternate to Site PEAT-5C) targets the Oligocene and is located on lower Oligocene crust. Our aims are to
• Obtain continuous and well-preserved equatorial sections during a time of relatively deep CCD to extend and supplement existing astronomical time calibrations
• Investigate how a "e;one cold pole" world might impact the inter-hemispheric temperature imbalance on pole-to-Equator temperature gradients and on the symmetry of the global wind systems
• Gain new information on the position of trade winds, the position of the ITCZ, and the seasonal shifts in this zone, as reflected by the wind-driven currents of the equatorial region
• Form a limited depth transect with Sites PEAT-4C and 6C
Drilling program:
• Holes A, B, and C: APC with core orientation to refusal; XCB to basement; logging in Hole A
• 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/nannofossil ooze, nannofossil ooze/chalk, possibility of thin diatom layers, hydrothermically altered ridge basalt; low possibility of chert strings