Site Summaries
Site: PRB-1A
Priority: Alternate
Position: 9°00.40'S, 83°31.80'W
Water Depth: 4487 m
Sediment Thickness: 155 m
Target Drilling Depth: Through sediment-basement transition
Approved Maximum Penetration: 155 m (to 175 m requested to PPSP)
Seismic Coverage: Kana Keoki Leg 8 single-channel and 3.5-kHz seismic data. The site was also
surveyed during DSDP Leg 34, for which single-channel seismic data are also available, same
position as DSDP Site 320.
See seismic line.
Objectives:
1) Determine conditions under which subsurface microbes may be active, inactive but capable of
resuscitation, or dead.
2) Begin to assess the specialized metabolic strategies, if any, that are required to survive in deeply
buried marine sediments.
3) Explore phylogenetic affinities and differences between microbes of the organic-poor Peru
Basin sediments and nearby organic-rich Peru Margin sites.
Drilling Program: APC to refusal, XCB to TD. At least two holes, possibly three. Possible MDCB/RCB coring to improve recovery. Possible PCS deployment. May require additional mudline cores.
Logging and Downhole Program: APC-temperature, DVTP, and APC methane tool.
Nature of Rock Anticipated: Siliceous clay, nannofossil ooze, basaltic basement.
