Priority: 2 (alternate to APRIS-01A)
Position: 66°48.33'S, 75°56.78'W
Water Depth: 2960 m
Sediment Thickness: >2000 m
Approved Maximum Penetration: 1150 mbsf
Seismic Coverage: Line IT92-109 SP 3840; intersecting lines are AI95-138A SP 1120 and AI97-243 SP 4767.
Objectives: The objectives of Site APRIS-03A are to:
1. Obtain a high-resolution history of Antarctic Peninsula glaciation for the last 6-10 m.y.
2. Determine the onset of drift formation by sampling the base of Unit M4.
Drilling Program: Double APC until refusal (about 200 m), continue with XCB until refusal (about 800 m), and then either RCB from 750 m to base of target section at the same site or single APC and XCB to base of target section at Site APRIS-04. APRIS-04 is offset about 110 km from APRIS-03 and is located where the upper part of the section is thinner and the base of the target section is at only about 700 mbsf. Offset of the site is required if the stratigraphic control seriously degrades below the silica diagenetic BSR at about 670 mbsf at Site APRIS-03A.
Logging and Downhole Operations: Standard suites IPLT-DLT and FMS-sonic, plus GHMT.
Nature of Rock Anticipated: Alternating (interglacial) biosiliceous clay and (glacial) laminated barren gray clay, becoming claystone downhole.
To 178 Site APRIS-04
To 178 Table of Contents