Site Summaries (continued) | Table of Contents

SITE SUMMARIES (continued)

Site: SEPAC-5A

Priority: 3
Position: 46°19.02´S, 76°32.28´W
Water Depth: 2825 m
Sediment Thickness: 310 m
Target Drilling Depth: 310 mbsf
Approved Maximum Penetration: 350 mbsf (Site mislabeled as SEPAC-14A in PPSP report 1/23/01).
Seismic Coverage: Sediment Cover, TWTT = 0.41 s (310 m)
Primary Line: 970301 (Revelle), Line CRI-1B-2, 0615z, SP271
Crossing Line: 970301 (Revelle), Line CRI-1B-5, 1053z, SP139

Trackline map | Seismic Line 2 | Seismic Line 5 | Bathymetry map

Objectives: The objective at Site SEPAC-5A is to provide a continuous sedimentary sequence to obtain a high-resolution climate record of the entire Pleistocene from the shallowest possible site on the southern flank of Chile Rise (to maximize carbonate preservation). Benthic fauna are likely to monitor PCW, planktonic fauna to monitor the southward flowing Cape Horn Current, and terrigenous components to record glacial erosion of the Southern Andes (including a potential record of ice-rafting in an area that should not contain turbidites).

Drilling Program: Triple APC to refusal. Tensor orientation on APC cores. Single XCB to basement or refusal (expected penetration ~310 mbsf).

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

Nature of Rock Anticipated: Site SEPAC-5A is in an area of thick sediment cover on abyssal hill topography near the crest of Chile Rise. Based on proximity to the rise crest and known spreading rates, we estimate crustal ages at 2-3 Ma. Thus, high sedimentation rates are probable (100-150 m/m.y.). Sediments appear to be pelagic or hemipelagic clay, draped over the abyssal hill topography. Cores taken during the site survey reveal substantial intervals barren of both carbonate and siliceous fossils, and as a result the priority of this site is 3.

Site Summaries (continued) | Table of Contents