United States Department of the Interior



GEOLOGICAL SURVEY

 GLORIA Survey 87-5

    Cruise Report


Ship Name:                R/V FARNELLA

Dates:                    9-28 May 1987

Project Title:            Gloria Survey

Area of Operation:        Blake Plateau & Blake Escarpment within 200 miles of
                          the Bahamas and southeastern United States.

Chief Scientists:         William P. Dillon, U.S. Geological Survey
                          Kathryn M. Scanlon, U.S. Geological Survey

Other Participants:       Page Valentine, geologist        U.S. Geological Survey
                          Linda Sheetz, geologist                     "
                          Renato Diaz, geologist                      "
                          Michael Boyle, technician                   "
                          Quentin Huggett, geologist       Inst. of Oceanographic
                          Derek Bishop, engineer                 Sciences, U.K
                          Christopher Flewellen, engineer     "
                          Doriel Jones, computer specialist	  "
                          Graham Lake, technician		  "
                          Emma Woodward, geologist		  "

Operating Institution: United States Geological Survey, Branch of Atlantic
                       Marine Geology, Woods Hole, MA 02543

Ports:                    9 May 87 depart Norfolk, VA
                          28 May 87 arrive Nassau, Bahamas
                          30 May 87 depart Nassau, Bahamas

Clearance Countries:      Bahamas



Cruise Objectives:   This cruise was the fifth in a series of five cruises
aimed at surveying the Exclusive Economic Zone (EEZ) of the eastern United
States.  Permission was granted by the government of the Bahamas to extend the
survey south into Bahamian waters in order to map prominent geologic features
more completely.

     The main survey instrument was GLORIA II, a long-range sidescan-sonar
system that is well-suited to deep-water reconnaissance mapping of large
areas.  A seismic-reflection profiler, magnetometer, and 3.5 and 10 kHz echo-
sounders were operated simultaneously with the GLORIA system throughout most
of the cruise.

     A large part of the survey area is covered by the Blake Plateau a broad,
shallow (800-1200 m) carbonate bank that lies east of Florida and north of
Grand Bahama and Great Abaco Islands.  The eastern edge of the Plateau is
bounded by a nearly vertical 3500 meter cliff called the Blake Escarpment.

Cruise Results:   Superb weather conditions and minimum equipment down time
 combined to make a most successful cruise. About three days were spent
 surveying gaps in the previous cruises coverage. Of the remaining 14 days,
 12 were spent surveying the Blake Plateau and Escarpment within the U.S. EEZ
 and 2 were used to survey the southern extension of the Escarpment into
 Bahamian waters. The GLORIA system was run well into Northeast Providence
 Channel before docking at Nassau.  Figure 1 shows the ship's tracks for the
 entire cruise.  Preliminary mosaics of the overlapping GLORIA image data were
 built by hand onboard the ship.  A photograph of the southern part of the
 mosaic, which includes all of the imagery collected in Bahamian waters, is
 shown in Figure 2.   Further corrections and enhancements will be done at the
 shore facility in Woods Hole where a digital mosaic can be produced. United
 States Ambassador Hallett held a reception for the Governor General of the
 Bahamas onboard the Farnella at the Nassau dock.  The guest list included:

Governor General, His Excellency Sir Gerald Cash
His Excellency the British High Commissioner Mr. Mays
Minister of Economic Affairs Alfred Maycock
Commodore Leon Smith, Royal Bahamas Defense Force
Mr. Francis Garraway, Dept. of Lands & Surveys
Mr. Ronald Thompson - Dir., Dept. of Agriculture, Fisheries & Cooperatives
Mr. Colyn Higgs - Dep.  Dir., Dept. of Agriculture, Fisheries & Cooperatives
Mrs. Judy Blair - College of the Bahamas, Natural Science Div.
Ms. Joy Chaplin - College of the Bahamas, Natural Science Div.
Mr. Peter Key - Government High School
Mr. Gary Lawson - Bahamas National Trust
Mr. Richard Kench - Ministry of Works
Mrs. Camille Cartwright - Ministry of Economic Affairs



Information Address:

William P. Dillon
U.S. Geological Survey
Woods Hole, MA   02543   USA



Schedule of delivery for data:
     
Data                                      Delivery


Preliminary GLORIA sidescan sonar         accompanies this report.
mosaic

Computer enhanced GLORIA mosaic           March 1989

Seismic profiles collected with           March 1989
GLORIA data


Line miles of data- GLORIA, 12 kHz and airgun seismic profiles, and
total intensity of magnetic field were collected as follows:

-Northeastern cleanup		1362 km
-Northern Blake Escarpment	1511 km
-Blake Plateau			2858 km
-Southern Blake Escarpment	 397 km
-Transit to Nassau		 291 km 
(all data types continued to be collected)

		total: 6419 km