Site Summaries
Site: PRU-4A
Priority: Primary
Position: 9° 06.78'S, 80°35.01'W
Water Depth: 5071 m
Sediment Thickness: >468 m
Target Drilling Depth: 300 m
Approved Maximum Penetration: 200 m (to 300 m requested to PPSP)
Seismic Coverage: Single-channel seismic line CDP-2. Charcot line 17 crosses common depth
point (CDP) 2 ~2.5 km southwest of Site PRU-4A, same position as ODP Site 685.
See seismic line.
Objectives:
1) Test how hydrate-bearing sequences differ in microbial activity and community structure from
nearby methane-rich sequences that lack hydrates (proposed Sites PRU-1A and PRU-3A).
2) Provide a Peru Margin microbial and biogeochemical counterpoint to the hydrate-rich sites
targeted for coring during Leg 204 (Hydrate Ridge).
Drilling Program: APC to refusal, XCB to TD. At least two holes, possibly three. Possible MDCB/RCB coring to improve recovery. PCS test site. May require additional mudline cores.
Logging and Downhole Program: Triple combo, possible FMS, APC-temperature, DVTP, and APC methane tool.
Nature of Rock Anticipated: Diatomaceous mud and mudstone.
