IODP Expedition 320/321 Scientific Prospectus

doi:10.2204/iodp.sp.320321.2008

Site summaries (continued)


PEAT-1 Line 8:	2006 JD 098 05:57:59 UTC SP 42439
Nearest crossing:	Line 1 crosses Line 8 at 2006 JD 097 19:13:47 UTC, SP 38579
Estimated crustal age (Ma):	53
Ship location:	SP 42439: 12°04.039’N, 142°09.692’W
Basement depth (m):	5319 (7.078 s TWT)
Sediment thickness (m):	187 Estimated from Leg 199 composite (0.236 s TWT)
Velocity (Busch et al., 2006):	Depth (mbsf)	TWT (ms)	Velocity (m/s)
	0–50	0–65	1540
	50–250	65–315	1600
	250–TD	>315	1660
Site PEAT-1C was sited south of the intersection between Lines 1 and 8 because the basal seismic horizons look weaker but are well imaged. The lack of nearby hills implies that this change is not the result of out-of-plane geometry. We looked for less strong basal seismic horizons to avoid cherts as much as possible. The sediment section is slightly thicker than average for the PEAT-1C survey region.