SITE: APRIS-01A PRIORITY: 1 POSITION: 67° 34.00'S, 76° 57.78'W WATER DEPTH: 3200 m SEDIMENT THICKNESS: >2000 m TOTAL PENETRATION: 700 m SEISMIC COVERAGE: Explora lines IT92-109 and AI95-130Objectives: Sample long continuous section in fine-grained hemipelagic drift to Base M4, the onset of drift formation. Prime section is in Drift 7 (because of its thick section), but with alternates in Drift 6 and Drift 4. Each section comprises two sites: a main and a standby distal (~50 km) offset. Offset required if stratigraphic control seriously degraded below silica diagenetic BSR at ~600 m at main site.
Drilling Program: Double APC to 200 m and XCB to 700 m, then either RCB from 700 m to base M4 at same site OR single APC and XCB to base M4 (at ~550 m) at offset site (APRIS-02A), where upper section is thinner. Alternates APRIS-03A, -05A
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.
SITE: APRIS-02A PRIORITY: 1 POSITION: 66° 59.91'S, 78° 29.16'W WATER DEPTH: 3850 m SEDIMENT THICKNESS: 1500 m TOTAL PENETRATION: 550 m SEISMIC COVERAGE: Explora line AI95-135AObjectives: Sample long continuous section in fine-grained hemipelagic drift to Base M4, the onset of drift formation. Is standby distal (~50 km) offset to main Site APRIS-01A. Offset required if stratigraphic control seriously degraded below silica diagenetic BSR at ~600 m at main site.
Drilling Program: Single APC and XCB to base M4 (at ~550 m) where upper section is thinner. Alternate Sites APRIS-04A, -06A
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.
SITE: APSHE-01A PRIORITY: 1 POSITION: 63° 48.16'S, 65° 51.46'W WATER DEPTH: 450 m SEDIMENT THICKNESS: >2000 m TOTAL PENETRATION: 505 m SEISMIC COVERAGE: Explora line AI95-152 and Discovery line AMG845-08Objectives: Part of a 4-hole transect along the axis of progradational Lobe 1 to identify and date the main changes in wedge geometry (including the "pre-glacial"/glacial transition), examine foreset and topset lithologies, and compare with rise drift. This site contains young S1 foresets from the present shelf break. Lobe 1 was selected on the basis of site survey: better definition of sequence boundaries than the alternate on Lobe 3 and a more extensive dataset.
Drilling Program: Single RCB hole. Alternate site is Site APSHE-07A
Logging and Downhole Operations: Standard suites IPLT-DLT and FMS-sonic, plus GHMT.
Nature of Rock Anticipated: Diamicton (mainly proximal glacial marine) with thin biosiliceous interbeds
SITE: APSHE-02A PRIORITY: 1 POSITION: 63° 52.03'S, 65° 44.73'W WATER DEPTH: 440 m SEDIMENT THICKNESS: >2000 m TOTAL PENETRATION: 560 m SEISMIC COVERAGE: Explora line AI95-152 and Discovery line AMG845-08Objectives: Part of a 4-hole transect (each a single rotary cored hole) along the axis of progradational Lobe 1 to identify and date the main changes in wedge geometry (including the "pre-glacial"/glacial transition), examine foreset and topset lithologies, and compare with rise drift. This site contains S1 topsets down to the onset of S1 deposition (when topset deposition recommenced), where the S1/S2 boundary is conformable, then upper S2 foresets.
Drilling Program: Single RCB hole. Alternate site is Site APSHE-08A
Logging and Downhole Operations: Standard suites IPLT-DLT and FMS-sonic, plus GHMT.
Nature of Rock Anticipated: Diamicton (alternations of lodgement till in topsets and proximal glacial marine) with thin biosiliceous interbeds
SITE: APSHE-03A PRIORITY: 1 POSITION: 63° 52.93'S, 65° 42.69'W WATER DEPTH: 440 m SEDIMENT THICKNESS: >2000 m TOTAL PENETRATION: 505 m SEISMIC COVERAGE: Explora line AI95-152 and Discovery line AMG845-08Objectives: Part of a 4-hole transect along the axis of progradational Lobe 1 to identify and date the main changes in wedge geometry (including the "pre-glacial"/glacial transition), examine foreset and topset lithologies, and compare with rise drift. This site contains the time when erosion of S2 topsets started (NOT the same as Apshe-02A).
Drilling Program: Single RCB hole. Alternate site is Site APSHE-09A.
Logging and Downhole Operations: Standard suites IPLT-DLT and FMS-sonic, plus GHMT.
Nature of Rock Anticipated: Diamicton (alternations of lodgement till in topsets and proximal glacial marine) with thin biosiliceous interbeds
SITE: APSHE-04A PRIORITY: 1 POSITION: 63° 56.52'S, 65° 34.62'W WATER DEPTH: 490 m SEDIMENT THICKNESS: >2000 m TOTAL PENETRATION: 785 m SEISMIC COVERAGE: Explora line AI95-152 and Discovery line AMG845-08Objectives: Part of a 4-hole transect along the axis of progradational Lobe 1 to identify and date the main changes in wedge geometry (including the "pre-glacial"/glacial transition), examine foreset and topset lithologies, and compare with rise drift. At this site, the oldest part of S2 and youngest ("pre-glacial") S3, where the boundary is conformable.
Drilling Program: Single RCB hole. Alternate site is Site APSHE-05A.
Logging and Downhole Operations: Standard suites IPLT-DLT and FMS-sonic, plus GHMT.
Nature of Rock Anticipated: Diamicton (alternations of lodgement till in topsets and proximal glacial marine) with thin biosiliceous interbeds to base S2, then uncertain lithology (glacial marine diamicton or biosiliceous hemipelagic)
SITE: APSHE-05A PRIORITY: 1 POSITION: 66° 23.57'S, 70° 45.40'W WATER DEPTH: 600 m SEDIMENT THICKNESS: >2000 m TOTAL PENETRATION: 785 m SEISMIC COVERAGE: Polar Duke PD88-B and PD88-04Objectives: To examine ("pre-glacial") S3 in detail, test the synchroneity of the conformable S3/S2 boundary along the margin, and sample the near-conformable (probably tectonic) S4/S3 boundary. Will test hypotheses of the "pre-glacial" nature of S3, and of the uplift/subsidence origin of the S4/S3 boundary. Required to be remote from the main wedge transect, and better in an older RC-T collision zone. Access to S3 is eased by site location in interlobe area.
Drilling Program: Single RCB hole. Alternate site is Site APSHE-10A.
Logging and Downhole Operations: Nature of Rock Anticipated: Diamicton (lodgement till and proximal glacial marine) with thin biosiliceous interbeds to base S2 (ie top ~150 m), then uncertain (glacial marine diamicton or biosiliceous hemipelagic) in S3 to base of hole
SITE: APSHE-13A PRIORITY: 1 POSITION: 64° 51.72'S, 64° 12.51'W WATER DEPTH: 1040 m SEDIMENT THICKNESS: ~60 m TOTAL PENETRATION: 50 m SEISMIC COVERAGE: PD92 Deep-tow Boomer (Explora lines planned 3/97)Objectives: Ultra-high-resolution Holocene record of paleoproductivity (from Domack et al., Proposal 502) in inner shelf basin. Examine decadal-millennial variability, compare with low-latitude and ice core records.
Drilling Program: Quadruple APC to 50 m or base of biogenic sediments if deeper. Alternate site is Site APSHE-14A
Logging and Downhole Operations: None
Nature of Rock Anticipated: Pelagic/hemipelagic siliceous ooze and mud, with <1% ice-rafted component (??diamicton at base)