Site summaries (continued)

Proposed Site PEAT-6C (Oligocene–Miocene transition)

Primary for Expedition 321, alternate for Expedition 320
05°18.736’N, 126°16.997’W (WGS-84)
Water depth (m):
4362 (5.816 s TWT)
Target drilling depth (mbsf):
362 then tag basement
Approved maximum penetration (mbsf):
400 (approved by TAMU safety panel based on EPSP June 2006 recommendation)
Survey coverage (track map; seismic profile):
Roger Revelle (27–28 March 2006):
• Simrad EM-120 multibeam system
• Knudsen 320B subbottom profiler
• Dual 150 c.i. GI seismic sources
• Scripps 48-channel Geometrics GeoEel
Piston core: 12.67 m (RR0603-06JC)
Primary seismic line: PEAT-6 Line 8
Crossline: PEAT-6 Line 1 (Figs. F27, F28, F29) (see also report to the EPSP panel, available at
Site PEAT-6C, on 26 Ma crust, focuses on the paleoceanographic events in the late Oligocene and into the early and middle Miocene, including the climatically significant Oligocene–Miocene transition and its recovery.
In conjunction with Sites PEAT-5C and 7C it is also designed to provide a latitudinal transect for early Miocene age slices, as well as a limited depth transect.
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:
• Wireline logging: triple combo, FMS-sonic
• Check shot survey with VSI
• 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