Site Summaries (continued) | Table of Contents

SITE SUMMARIES (continued)

Site: COC-2A

Priority: 3
Position: 5°50.566'N 86°26.674'W
Water Depth: 2042 m
Sediment Thickness: 404 m
Target Drilling Depth: 410 mbsf
Approved Maximum Penetration: 450 mbsf
Seismic Coverage: Sediment thickness: TWTT = 0.49 s (404 m)
Primary Site: 2000 NEMO-3 (Melville), COC-2 survey Line 1, JD144 21:02:21z (SP964)
Crossing Line: 2000 NEMO-3 (Melville), COC-2 survey Line 3, JD145 08:34:09z (SP3044)

Seismic Line 1 | Seismic Line 3 | Bathymetry map

Objectives: The objectives at Site COC-2A are to provide a continuous sedimentary sequence to:

1. Study of the connection between the tropics and northeast Pacific Ocean. The site is located roughly under the modern northern summer position of the Intertropical Convergence Zone.

2. Assess carbonate dissolution within Guatemala Basin.

Drilling Program: Triple APC to refusal. Tensor orientation on APC cores. Single XCB to extend one hole to basement or refusal (expected penetration ~280 mbsf).

Logging and Downhole: Triple combo, third-party Lamont MGT, FMS/sonic, GHMT.

Nature of Rock Anticipated: Nannofossil ooze, lithifying to chalk at depth. Crustal age of 10-15 m.y. and a sediment thickness (from the seismic survey) of 404 m yields an average Neogene sedimentation rate of 25-40 m/m.y. Basement is likely composed of volcanics from Galapagos hotspot.

Site Summaries (continued) | Table of Contents