Site summaries (continued)

Proposed Site LOUI-8B (Seamount 36.9°S - Nintoku equivalent)

Priority: Alternate site
Position: 36°56.64′S, 169°45.76′W
Water depth (m): 960
Target drilling depth (mbsf): Hole A: APC core to ~55 (50 m pelagic sediment) Hole B: RCB core to ~480 (130 m sediment; ≥350 m basement)
Approved maximum penetration (mbsf): Approval pending (480 m requested)
Survey coverage: • AMAT02RR (Fig. AF7)
• Line AMAT 36.9-3 (CDP 22010) (Fig. AF20)
Objective: (see text for details) Hole A: Core thin sediment cover with APC to contribute to southern hemisphere paleoclimate record.
Hole B: (1) Core thin sediment cover and igneous basement until enough igneous units suitable to acquire accurate paleolatitudes and 40Ar/39Ar ages are recovered. (2) Study the geochemical evolution of this guyot.
Drilling, coring, and downhole measurement program: • Hole A:
APC coring to TD.
• Hole B:
RCB coring to TD.
FFF deployment and two bit changes (two reentries).
Wireline logging (triple combo, FMS-sonic, and magnetometer).
Anticipated lithology (mbsf): • 0–50: pelagic ooze
• 50–130: lithified limestones, volcaniclastics, and minor lava flows(?)
• >130: basalt (~54 m.y. old)
Site characterization: This alternate drilling site is located on the same seamount targeted for Sites LOUI-3B and LOUI-8A on the 36.9°S guyot. Its interpolated age of 54 Ma is very close to the 56 Ma age of Nintoku Seamount in the Emperor Seamount Trail. Its estimated pelagic cap is well layered and, at ~50 m thick, is thicker than the cap at Site LOUI-3B and slightly thicker than the cap at Site LOUI-8A based on 3.5 kHz CHIRP data. This site has the thickest sediment cover of all Louisville sites and is proposed as a possible site for contingency APC coring. In addition, a potential B Hole could serve as an additional alternate site for primary Site LOUI-3B.