ALTERNATE SITE SUMMARIESSite: OJ-7E (Alternate)
Position: 7°13.04´S, 161°17.53´E
Water Depth: 1635 m
Sediment Thickness: 1305 m
Target Drilling Depth: 1405 mbsf
Approved Maximum Penetration: 1505 mbsf
Seismic Coverage: R/V Maurice Ewing EW95-11 Line 1.
Objectives: The objectives of Site OJ-7E are to
1. Obtain a minimum of 100 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 500 mbsf to the
4. Determine a minimum basement age using overlying sediments and ages of possible sediment
5. Define the ages of seismic sequence boundaries.
6. Determine early subsidence history and duration of possible subaerial environment.
Drilling Program: Drill without coring to 500 mbsf, then RCB to bottom of hole.
Logging and Downhole: Triple combo, FMS/sonic, and WST (cored section only).
Nature of Rock Anticipated: Limestone, chert, and basalt.
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