PRIMARY SITE SUMMARIES

Priority: 1
Position: 1°10.62´S, 157°0.89´E
Water Depth: 1800 m
Sediment Thickness: 1175 m
Target Drilling Depth: 1325 mbsf
Approved Maximum Penetration: 1475 mbsf
Seismic Coverage: Multichannel seismic line; R/V Hakuho Maru KH98-1 Leg 2 Line 404.

Objectives: The objectives of Site OJ-3B are to

1. Obtain a minimum of 150 m of basaltic basement to determine lava composition and age.

2. Determine lava-flow thickness and flow morphology and, hence, deduce eruptive environment.

3. Obtain sedimentary record and determine sequence facies from 800 mbsf to the
sediment/basement interface.

4. Determine a minimum basement age using overlying sediments and ages of possible sediment
interbeds.

5. Define the ages of seismic sequence boundaries.

6. Determine early subsidence history and duration of possible subaerial environment.

Drilling Program: Double case reentry hole to 350 mbsf, drill without coring to 800 mbsf, then
RCB to bottom of hole.

Logging and Downhole: Triple combo, FMS/sonic and WST (cored section only).

Nature of Rock Anticipated: Chalk, limestone, chert, and basalt.