SITE SUMMARIES

Priority: 2 (alternate)
Position: 50°57'N, 167°44.4'E
Water Depth: 2773 m
Sediment Thickness: 500 m
Target Drilling Depth: >650 m
Approved Maximum Penetration: 800 mbsf
Seismic Coverage: Thomas Washington, 88, JD 226, 1627 UTC

Seismic line for Site HE-3A (east-west)
Seismic line for Site HE-3A (north-south)

Objectives: The objectives of Site HE-3A are to:

1.Obtain a paleolatitude and age estimate for Detroit Seamount with enough independent time units (>15) to provide increased resolution in tests of the fixed-hotspot hypothesis

2. Determine the geochemical signature of the Detroit Seamount

3. Determine the nature of the time-averaged geomagnetic field

4. Determine the paleointensity of the geomagnetic field

5. Constrain downhole magnetic structure through borehole magnetic logging

Drilling Program: RCB

Logging and Downhole: Triple combo, FMS, third-party magnetic tool

Nature of Rock Anticipated: Quartz/diatom clay, diatom clay/ooze, diatom ooze with calcareous diatom ooze, volcanic ash, chalk, altered ash and claystone, and tholeiitic olivine basalt