Technical Note 20/5


LEG 177 PROSPECTUS

Table 1. Proposed Site Information and Drilling Strategy


SITE: TSO-2B		PRIORITY: 1			POSITION: 41° 8.20'S, 13° 33.65'E
WATER DEPTH: 2104 m	SEDIMENT THICKNESS: 1300 m	TOTAL PENETRATION: 800 m
SEISMIC COVERAGE: TN057/TSO-2, shot point TN1100
Objectives: Recover a Cenozoic carbonate record that can be used to reconstruct long-term changes in surface water parameters and the evolution of the Subtropical Front, paleoproductivity north of the Polar Front Zone, mixing ratio between CPDW and upper NADW, and paleodepth history of the Agulhas Ridge.

Drilling Program: Single APC to 200 m, XCB to 400 m, RCB to 800 m

Logging and Downhole Operations: Quad combo, GLT, GHMT, and FMS logs

Nature of Rock Anticipated: Nannofossil-foraminiferal ooze, chalk, limestone.


SITE: SubSAT-1C  		PRIORITY: 1			POSITION: 40° 54.83'S, 9° 55.48'E
WATER DEPTH: 4620 m	SEDIMENT THICKNESS: 1500 m	TOTAL PENETRATION: 300 m
SEISMIC COVERAGE: TN057/SubSAT-1, shot point TN3060
Objectives: Recover an expanded Pleistocene section at sedimentation rates >20 cm per 1000 yrs to study the response of Southern Ocean to orbital forcing, phase relationships with high-latitude Northern Hemisphere, rapid climate change on suborbital (millennial) time scales, correlation to Greenland and Antarctic ice cores.

Drilling Program: Triple APC/XCB to 300 m

Logging and Downhole Operations: None

Nature of Rock Anticipated: Diatomaceous calcareous mud


SITE: TSO-3C		PRIORITY:	1		POSITION: 42° 54.82'S, 8° 53.99'E	
WATER DEPTH: 3718 m	SEDIMENT THICKNESS: 800 m	TOTAL PENETRATION: 200 m
SEISMIC COVERAGE: TN057/TSO3, shot point TN1850
Objectives: Recovery of a continuous composite section of the Plio-Pleistocene at sedimentation rates of 3 cm per 1000 yrs to study past migrations in the PFZ, mixing ratios of lower NADW and CPDW, response of the Southern Ocean to orbital forcing and phase relationships with Northern Hemisphere, and stability of the Antarctic cryosphere under "warmer-than-present climate during the Pliocene.

Drilling Program: Triple APC to 200 m

Logging and Downhole Operations: None

Nature of Rock Anticipated: Foram-nannofossil ooze


SITE: TSO-5B		PRIORITY:	1		POSITION: 47° 7.22'S, 5° 50.68'E
WATER DEPTH: 4418 m	SEDIMENT THICKNESS: 1200 m	TOTAL PENETRATION: 200 m
SEISMIC COVERAGE: TN057/TSO5, shot point TN3450
Objectives: Recovery of a continuous composite section of the late Pliocene-Pleistocene at sedimentation rates of 8 cm per 1000 yrs to reconstruct surface water parameters and the PFZ, paleoproductivity changes, properties of CPDW and AABW, orbital forcing and phase relationships of proxy records.

Drilling Program: Triple APC to 200 m.

Logging and Downhole Operations: None

Nature of Rock Anticipated: Calcareous-bearing diatom ooze


SITE: TSO-6A		PRIORITY: 1			POSITION: 49° 58.58'S, 5° 51.92'E
WATER DEPTH: 3680 m	SEDIMENT THICKNESS: 1100 m	TOTAL PENETRATION: 700 m
SEISMIC COVERAGE: AWI94090, shot point PS916
Objectives: Recovery of late Cenozoic biosiliceous and calcareous sediments in mid-water depths on Shona Ridge to study surface water parameters and evolution of the PFZ, sea-ice distribution in the Southern Ocean, paleoproductivity changes and history of circum-Antarctic biogenic silica belt, physical and chemical properties of CPDW, and silica diagenesis.

Drilling Program: Triple APC to 200 m, XCB to 400 m, RCB to 700 m.

Logging and Downhole Operations: Nature of Rock Anticipated: Foram-bearing diatom ooze, calcareous diatom ooze, diatomaceous nannofossil chalk, limestone


SITE: TSO-6B		PRIORITY:	2		POSITION: 50° 0.98'S, 5° 50.13'E
WATER DEPTH: 3679 m	SEDIMENT THICKNESS: 1100 m	TOTAL PENETRATION: 700 m
SEISMIC COVERAGE: TN057/TSO6, shot point TN650
Objectives: Alternate to TSO-6A in the event primary site is occupied by ice berg. Objectives same as TSO-6A.

Drilling Program: Triple APC to 200 m, XCB to 400 m, RCB to 700 m.

Logging and Downhole Operations: Quad combo, GLT, GHMT, and FMS logs.

Nature of Rock Anticipated: Foram-bearing diatom ooze, calcareous diatom ooze, diatomaceous nannofossil chalk, limestone


SITE: TSO-7C		PRIORITY:	1		POSITION: 53° 10.84'S, 5° 7.67'E
WATER DEPTH: 2850 m	SEDIMENT THICKNESS: 1000 m	TOTAL PENETRATION: 200 m
SEISMIC COVERAGE: AWI94080, CDP 660		*max 730 m
Objectives: Recovery of an ultra-high resolution record of biosiliceous sediments south of the PFZ to study rapid climate change on suborbital time scales, surface water parameters, sea-ice distribution, paleoproductivity changes, deep-water circulation changes and properties of CPDW, and early, low temperature silica diagenesis.

Drilling Program: Triple APC to 200 m, XCB to 400 m, RCB to 730 m. *This site may be deepened to maximum of 730 m, if time permits at the end of Leg 177.

Logging and Downhole Operations: None

Nature of Rock Anticipated: Foram-bearing diatom ooze


SITE: TSO-7B		PRIORITY:	2		POSITION: 53° 12.95'S, 5° 8.07'E	
WATER DEPTH: 2925 m	SEDIMENT THICKNESS: 1000 m	TOTAL PENETRATION: 200 m
SEISMIC COVERAGE: AWI94080, shot point PS335		*max 730 m
Objectives: Alternate to TSO-7C in the event primary site is occupied by ice berg. Objectives same as TSO-7C.

Drilling Program: Triple APC to 200 m, XCB to 400 m, RCB to 730 m. *This site may be deepened to a maximum of 730 m, if time permits at the end of Leg 177.

Logging and Downhole Operations: None

Nature of Rock Anticipated: Foram-bearing diatom ooze


SITE: TSO-4B		PRIORITY:	2		POSITION: 43° 11.33'S, 11° 43.62'E	
WATER DEPTH: 4630 m	SEDIMENT THICKNESS: 1600 m	TOTAL PENETRATION: 500 m 
SEISMIC COVERAGE: AWI 94100, shot point PS3245
Objectives: Recovery of a Cenozoic sequence to reconstruct surface water parameters and paleoproductivity north of the Polar Front, history of deep and bottom water masses related to the establishment of Southern Hemisphere cryosphere, and calibration of biostratigraphic markers.

Drilling Program: Single APC to 200 m, XCB to 400 m, RCB to 500 m

Logging and Downhole Operations: Quad combo, GLT, GHMT, and FMS logs

Nature of Rock Anticipated: Calcareous diatomaceous mud and mudstone


SITE: SubSAT-3B	PRIORITY:	2		POSITION: 46° 24.7'S, 7° 4.79'E	
WATER DEPTH: 2008 m	SEDIMENT THICKNESS: 1600 m	TOTAL PENETRATION: 200 m
SEISMIC COVERAGE: TN057/SubSAT3, shotpoint TN1200
Objectives: Recover upper 200 m of section that was disturbed and incomplete at ODP Site 704 to study past migrations in the position of the PFZ, changes in mixing ratios of upper NADW and CPDW, and stability of the Antarctic cryosphere during "warmer-than-present" climate during the Pliocene.

Drilling Program: Triple APC to 200 m

Logging and Downhole Operations: None

Nature of Rock Anticipated: Alternating calcareous and siliceous ooze


SITE: SubSAT-4B	PRIORITY:	2		POSITION: 52° 3.01'S, 4° 31.01'E	
WATER DEPTH: 3661 m	SEDIMENT THICKNESS: 1100 m	TOTAL PENETRATION: 700 m
SEISMIC COVERAGE: TN057/SubSAT4, shotpoint TN1800
Objectives: SubSAT-4B will serve as a backup to either TSO-6A or TSO-7C. The objectives are essentially the same as those outlined for those sites.

Drilling Program: Triple APC to 200 m, XCB to 400 m, RCB to 700 m

Logging and Downhole Operations: Quad combo, GLT, GHMT, and FMS logs

Nature of Rock Anticipated: Foram-bearing diatom ooze, calcareous diatom ooze, diatomaceous nannofossil chalk, limestone


SITE: SubSAT-4C	PRIORITY:	2		POSITION: 51° 59.08'S, 4° 31.0'E	
WATER DEPTH: 3701 m	SEDIMENT THICKNESS: 1100 m	TOTAL PENETRATION: 700 m
SEISMIC COVERAGE: TN057/SubSAT4, shotpoint TN4210
Objectives: SubSAT-4C will serve as a backup to SubSAT-4B.

Drilling Program: Triple APC to 200 m, XCB to 400 m, RCB to 700 m

Logging and Downhole Operations: Quad combo, GLT, GHMT, and FMS logs

Nature of Rock Anticipated: Foram-bearing diatom ooze, calcareous diatom ooze, diatomaceous nannofossil chalk, limestone


To Leg 178

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