Site: 735

Priority: 1
Position: 32°43.31'S, 57°15.864'E
Water Depth
: 731 m
Sediment Thickness
: 0 m
Approved Maximum Penetration
: As deep as possible
Seismic Coverage:
Single channel: RC 27-09, Oct. 13 1630-2000

1.Obtain a section of layer 3 gabbros to adequately document the nature of magmatic, hydrothermal, and tectonic processes in the lower ocean crust at a slow-spreading ridge.
2.Determine if the boundary between igneous crust and the depleted mantle lies above the Mohorovicic discontinuity.

Drilling Program: Multiple reentry with rotary coring bits in existing Hole 735B. If conditions preclude deepening Hole 735B, offset ~500 m and start a transect of multiple reentry holes.

Logging and Downhole: Full Schlumberger tool suite, VSP, magnetometer

Nature of Rock Anticipated: Massive amphibolite, gabbro, and partially serpentinized peridotite.

Site: SWIR 6

Priority: 2
31°21.5'S, 57°16'E
Water Depth: 4150 m
Sediment Thickness: 50 m
Approved Maximum Penetration: Bit-to-destruction
Seismic Coverage: Single Channel, RC 27-09 15 Oct '86 1230-1420, 12 Oct '86 1530-1720

Objectives: Obtain the basaltic carapace originally overlying Site 735B

Drilling Program: Single-bit penetration, bit-to-destruction

Logging and Downhole: None

Nature of Rock Anticipated: Pillow basalt

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