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Summary for Field Activity Number 1971-006-FA

Alternate Leg ID: UGEO Leg 6; CORPUS 21

Area of Operations: transatlantic westward crossing, Liberia, Africa, Sierra Leone Rise, Vema Fracture Zone, mid-Atlantic Ridge, JOIDES 13,26,27, Charlotte Amalie, St. Thomas, U.S. Virgin Islands, Lesser Antilles, North Atlantic

Dates: November 24, 1971 to December 10, 1971

Objectives: Objectives of this cruise were: (a) to investigate the acoustic reflection characteristics of the mid-Atlantic ridge and other oceanic structures such as the Vema fracture zone and the Sierra Leone rise; (b) to correlate data from JOIDES drill holes with sub-bottom acoustic reflection profiles in oceanic areas; and (c) to extend our knowledge of sediment distribution and thickness in the deep ocean.

Type of Activity: Sub-bottom acoustic reflection

Information to be derived: Suspended sediment concentrations
Bathymetric maps
Magnetic intensity and gravity
Sub-bottom acoustic reflection profiles

Summary: The major result so far is that various geophysical data including continuous gravity, magnetics, and seismic reflection profiles and 18 seismic refraction and wide angle reflection (sonobuoy) profiles have been successfully recorded over a number of features. Gravity and magnetics records will require computer processing to be usable. Survey lines: 1, 2, 3, 4, 5, 6, 7, and 7A.

USGS Project Number: IDOE

Contact: Jim Robb (

Map for Area of Operations :

Map of field activity boundary.

Platform Info:
photo of UNITED GEO I
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