Seabed Assessment Program 



The goals of the Seabed Assessment Program are to expand ac- 

 tivities in gathering data on the geological structures and sedimen- 

 tary distributions of the continental margins, dynamic properties of 

 the ocean floor, and chemical and physical processes of the deep 

 ocean, particularly those which relate to potential economic re- 

 sources. In addition to a better understanding of the earth itself, 

 understanding of these ocean characteristics will prove valuable in 

 locating new resources in unexplored areas. 



The continental margins now produce 15 percent of the world's 

 supply of petroleum. As our resources on land decline, this per- 

 centage should increase. In addition, hard mineral, salt, sulfur, and 

 placer deposits are potential new resources. The continental mar- 

 gins remain largely unexplored outside the areas adjacent to the 

 economically more developed North Atlantic countries. 



Detailed studies of the continental margins around the South At- 

 lantic Ocean are now underway. Included are the Eastern Atlantic 

 Continental Margin Study of the area from Capetown, South Africa, 

 to Portugal and the Southwestern Atlantic Continental Margin 

 Study of the areas adjacent to Argentina and Brazil. Simultaneous 

 study of these areas has broad scientific appeal. The currently ac- 

 cepted "fit" of the continents made by Bullard and others suggests 

 that the original continental breakup and subsequent drifting must 

 have been relatively straightforward in the South Atlantic, thus 

 making this area an ideal location to test hypothetical models. The 

 South American coastline has numerous ridges and open-ended 

 basins trending perpendicular to the coastline with counterparts at 

 conjugate positions on opposing margins of Africa. Results and in- 

 terpretations from carefully conducted investigations of the South 

 Atlantic margins are applicable to other continental limits. 



K. O. Emery, Woods Hole Oceanographic Institution (WHOI), 

 is the Principal Investigator for the Eastern Atlantic Continental 

 Margin Study. Scientists from countries along the west coast of 

 Africa and Portugal are participating in various legs of the cruises 

 that began in 1972. Field work will be completed in 197.1; final 

 publication of results is scheduled for 1974. 



Special mention should be made of K. O. Emery's unpublished 

 manuscript. Woods Hole Oceanographic Institution 72-54, Eastern 

 Atlantic Continental Mar/^in Program of the International Decade 

 of Ocean Exploration (GX-28I93). Some Results of 1972 Cruise 

 of RV "Atlantis 11." This paper (funded under the Seabed Assess- 

 ment Program) describes a geophysical cruise to the southeastern 

 Atlantic during which a large ancient delta of the Orange River and 

 a diapiric field off Angola were mapped. These geographic features, 

 which may have future economic oil potential, began development 

 during early stages of the separation between Africa and .South 

 America. 



Emery and his associates prepared most of the report before the 

 Atlantis II returned to port in July 1972; printed copies were dis- 

 tributed that same month. Emery's effort emphasizes how rapidly 

 scientific information can be disseminated. 



G. Bryan, Lamont-Doherty Geological Observatory (L-DGO), is 

 coordinating the Southwestern Atlantic Continental Margin Study. 

 The geophysical data-gathering program off Argentina is completed, 

 and work off Brazil will begin in 1973. Petrobras, the Brazilian 

 National Oil Company, is funding WHOI scientists to carry out a 

 detailed study of the shallow waters along the Brazilian coast be- 

 ginning in late 1972. After finishing his work off the west coast of 



Africa in 1975. K. O. Emery plans to make geophysical observa- 

 tions along tracklines from the African coast to the Mid-Atlantic 

 Ridge, thereby tying the two Studies together. 



Several geophysical surveys in the mid-Atlantic and on the con- 

 tinental margins of some countries in the Gulf of Mexico-Caribbean 

 Sea region and off the coast of Liberia were completed in 1971 by 

 the United States Geological Survey (USGS) and NOAA. Data 

 from these surveys are now being analyzed. 



Lithospheric plate boundaries, including the midoceanic ridges 

 and deep trenches, are the areas of most tectonic activity. Heavy 

 metals are believed to rise to the surface along these ridges and 

 move toward the deep trenches. These metals, riding on the top of 

 the subducting lithospheric plate, are concentrated into major ore 

 deposits (in regions landward of trenches) above the descending 

 plate by complex distillation processes. The Nazca Lithospheric 

 Plate off the coast of Peru and Chile has been recognized as an 

 excellent example for detailed investigation of the complete 

 metalliferous cycle — from crustal formation along the East Pacific 

 Rise to its consumption in the Peru-Chile Trench. The major cop- 

 per, molybdenum, and tin deposits in the Andes are considered to 

 be the cycle's end products. 



The Nazca Plate is being studied in a cooperative program in- 

 volving the Hawaii Institute of Geophysics (HIG), Oregon State 

 University (OSU). and the Pacific Oceanographic Laboratory 

 (POL) of NOAA. The principal investigators are G. Woollard 

 (HIG), L. Kulm (OSU), and R. Burns (POL). Scientists from 

 Chile, Colombia, Ecuador, and Peru are also participating in this 

 study. The first cruises were completed in 1971 by the RV Katia 

 Keoki of HIG and RV Yaquina of OSU. Field work will continue 

 through 1975, with data analysis taking place in 1975-78. 



The East Pacific Rise extends northward into the Gulf of Cali- 

 fornia, where it is now under study by scientists from the Scripps 

 Institution of Oceanography and the University of Mexico. This 

 area is analogous to the Red Sea area, where heavy metals have 

 been detected in the hot brines. 



IDOE is also supporting a research program on the Mid-Atlantic 

 Ridge. As a first step, scientists from France and the United States 

 are planning extensive exploration of the ridge by use of submersi- 

 bles. Dives will begin in 1974. 



The widespread occurrence of manganese nodules, particularly 

 on the deep ocean floor, is also being studied. Although this oc- 

 currence has long been known, no systematic studies have ever 

 been made. IDOE is supporting a study which will bring together 

 the present knowledge on: (1) The origin and distribution of the 

 nodules, (2) technological problems that must be solved before 

 mining becomes economical, (3) environmental impact of mining 

 the abyssal depths of the ocean, and (4) legal status of a mining 

 operation beyond the limits of any claims to offshore sovereignty. 

 A coordinating office has been set up at Lamont-Doherty Geologi- 

 cal Observatory. 



Upon completion of the manganese nodule study, the Seabed 

 Assessment Program will support new research related to the origin 

 and distribution of the nodules. The results of these investigations 

 are expected to provide a basis for research by other agencies. 



SURVEYS AND DATA ANALYSIS 



During 1971, nine separate Seabed Assessment studies, involving 

 90,()()() nautical miles of marine geophysical surveys by research 



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