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.
