IODP

doi:10.2204/iodp.sp.329.2010

Site summaries (continued)

Site SPG-9A

Priority: Alternate
Position: 38°03.6871′S, 133°05.5024′W (WGS 84) (38.0615°S, 133.0917°W)
Water depth (m) 4925
Target drilling depth (mbsf): 20
Approved maximum penetration (mbsf): Until basement is encountered
Previous drilling in area: Closest drilling:
• DSDP Leg 92 Site 597, 1100 nmi away
Comments: International waters; 800 nmi from Pitcairn Island, United Kingdom Preferred weather window: November–December
Survey coverage (track map, seismic profile): High-resolution seismics:
• Primary line(s): MCS Line 4 - Shotpoint 12423 (Fig. AF22)
• Crossing line(s): MCS Line 1 - Shotpoint 13715 (Fig. AF23)
• Subbottom 3.5 kHz: Line 1 - JDay 011 at 03:49 GMT
• Detailed bathymetry and site location (swath bathymetry: collected with SIMRAD EM120) (Fig. AF24)
Sediment cores: Two piston cores, two trigger cores, one gravity core, and one eight-barrel multicore
Objectives (see text for complete details): • Document the habitats, metabolic activities, genetic composition, and biomass of microbial communities in subseafloor sediments with very low total activity.
• Test how oceanographic factors (such as surface ocean productivity) control variation in sedimentary habitats, activities, and communities from gyre center to gyre margin.
• Quantify the extent to which these sedimentary communities may be supplied with electron donors by water radiolysis, a process independent of the surface photosynthetic world.
Drilling/Coring program: • Quadruple APC to basement
• Temperature measurements: APCT-3
Downhole logging program: None specified
Anticipated lithology: Brown pelagic clay with rare foraminifers