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USGS Coastal and Marine Geology Program

Field Activity Details for field activity 1979-028-FA

Other ID: GS7903, Leg VII; GS 7903-7

Status: Completed

Organization(s): USGS, Woods Hole Coastal and Marine Science Center

Funding Program(s):

Principal Investigator(s): Mahlon M. Ball, Richard E. Sylwester

Affiliate Investigator(s): Wayne Bock - Rosentiel School of Marine and Atmospheric Sciences, U. Miami

Information Specialist(s):

Data Type(s): Electro-Magnetic: Gravity, Electro-Magnetic: Magnetics, Seismics: Multichannel, Location-Elevation: Navigation

Scientific Purpose/Goals: Leg VII was planned to obtain gravity, magnetic and seismic reflection data over the Destin Anticline in the northern part of the MAFLA or western Florida Shelf region. These data would have increased our ability to assess the hydrocarbon potential of this huge, partially tested structure. Unfortunately, Hurricane David forced delay in departure and Hurricane Frederick stalled over the work area during scheduled cruise time. We availed ourselves of the University of Miami's entree into the interesting marine geologic problems in Florida-Bahamas waters to obtain geophysical data in Florida Straits, Santaren and Nicholas Channels, north of Cuba in the vicinity of Cay Sal, Bahamas.


Start Port/Location: Miami, FL

End Port/Location: Miami, FL

Start Date: 1979-09-11

End Date: 1979-09-16

Equipment Used: Multichannel seismics, LaCoste-Romberg gravimeter G-179, Varian V-75 magnetometer, Bell Aerospace BGM-3 gravimeter, Western Geophysical Integrated Navigation System

Information to be Derived: Morphology;

Summary of Activity and Data Gathered: Our measurements recorded 2 anticlinal structures with dip reversals spanning several kilometers. These structures are large enough to constitute possible hydrocarbons exploration targets and occur in water depths less than 500 m, which is within currently drillable depths. Gravity data: 550 km; Magnetic data: 400 km; Seismic reflection data: 7 lines, 550 km.

Staff: Barry Irwin, David Mason, Kenneth E. Parolski, Ronald J. Miller, Mahlon M. Ball, Robert F. Bowles, John C., Jr. Hampson, Janet B. Burke, Elizabeth Coward, Alan Goodman, Kathleen Kent, Richard E. Sylwester, Charles W. Holmes

Affiliate Staff:
Wayne Bock - co-Ch. Sci.
Rosentiel School Marine/Atmospheric Sciences
U. Miami; Tom O'Brien - multichannel

Notes: Original Center People field contained: Mahlon Ball - Ch. Sci., Richard Sylwester - Ch. Sci., Robert Bowles - nav., Barry Irwin - nav., Janet Burke - sci., Alan Goodman - tech., Kenneth Parolski - tech., David Mason - mech. tech., Chuck Holmes - sci., Ronald Miller - sci., Jack Hampson - sci., Kathy Kent - multichannel, Elizabeth Coward - sci.
Project = Petroleum Geology of U.S. Atlantic and Gulf Margins, Petroleum Geology of U.S. Atlantic and Gulf Margins


Santaren Channel, Nicholas Channel, Cay Sal Bank, Bahamas, Straits of Florida, North America, North Atlantic;

North: 24.25 South: 23 West: -80.8 East: -78.75


photo of James  M Gilliss
James M Gilliss


Ball, M.M., Bowles, Robert L., Coward, Elizabeth L., and Dodd, James E., 1984, Multichannel seismic-reflection profiles collected aboard R/V GILLISS, Cruise GS7903, Leg 7, in Santaren and Nicholas Channels, near Cay Sal, southwestern Bahamas: U.S. Geological Survey Open-File Report 84-346, 3 p., URL:

Ball, M.M., ed., 1983, Multichannel seismic measurements on the northern edge of the Bahaman-Cuban collision zone: U.S. Geological Survey Open-File Report 83-23, 70 p., URL:


Data Acquired

Survey EquipmentSurvey InfoData Type(s)Data Collected
Bell Aerospace BGM-3 gravimeter --- Gravity
LaCoste-Romberg gravimeter G-179 --- Gravity
Varian V-75 magnetometer --- Magnetics
1979-028-FA-GP-001-01 ( Magnetic data)
Multichannel seismics --- Multichannel
1979-028-FA-SE-004-03 ( SEGY data files)
1979-028-FA-SE-004-01 ( Paper record section of Lines 1, 2, 3, 4, 5, 6, 7, )
1979-028-FA-SE-002 ( microfilm of )
1979-028-FA-SE-003 ( analog tape of seismic data)
1979-028-FA-SE-001 ( Collection of paper record displays of seismic data( AIR) for lines )
1979-028-FA-SE-004-02 ( Scanning line list)
Western Geophysical Integrated Navigation System --- Navigation
1979-028-FA-LN-002-01 ( Navigation data - all lines)
1979-028-FA-LN-001 ( Navigation trackline plot for field activity 79028)

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