Table 10. — U.S. institutions, investigators, and projects in Southwest Atlantic Continental Margin Study 



Institutions 



Investigators 



Projects 



Lamont-Doherty Geological 

 Observatory 



Woods Hole Oceanographic Institution 



G. M. Bryan 



I.W. D. Dalziel 

 J. E. Damuth and 

 N. Kumar 



M. A. Gorini 



N. Kumar 



W. Ludwig 

 R. Leyden 

 P. Rabinowitz 



J. D. Milliman and 

 C. P. Summerhayes 

 J. D. Milliman 



J. D. Milliman and 

 R. Fainstein 



Geophysical Study of the Continental Margins of 

 Brazil and Argentina 

 Evolution of Margins in the Scotia Sea 

 Amazon Cone: Morphology, sediments, age and 

 growth Pattern 

 Sedimentation Along Northeast Brazil Continental 

 Margins 



Tectonic Fabric of Equatorial Atlantic and Adjoin- 

 ing Continental Margins: Gulf of Guinea to North- 

 east Brazil 



Origin and Geologic History of Sao Paulo Plateau 

 (Southeastern Brazil Margin) 

 Origin and Evolution of Ceara Rise (west equatorial 

 Atlantic) 



Sedimentary Basins of Argentine Margins 

 Salt Diapirs Offshore Brazil 

 Mesozoic South Atlantic and Evolution of its Con- 

 tinental Margins 

 Upper Continental Margin 

 Sedimentation off Brazil 



Structure and History of three Continental Margin 

 Plateaus off Brazil (Pernambuco, Rio Grande Du 

 Norte, and Ceara) 

 Morphology and Structure of the Amazon Margin 



eastern South American margin. Geol. Soc. Am. Bull. 88: 



720-722. 



Houtz, R. E., W. J. Ludwig, J. D. Milliman, and J. A. Grow. 

 1977. Structure of the northern Brazilian continental margin. 

 Geol. Soc. Am. Bull. 88:7ri-719. 



Kowsmann, R., R. Leyden, and O. Francisconi. 



1977. Marine seismic investigations, southern Brazil margin. 

 Am. Assoc. Petr. Geol. Bull. 61:546-557. 



Kumar, N., and R. W. Embley. 



1977. Evolution and origin of Ceara Rise: an aseismic rise 

 in the western equatorial Atlantic. Geol. Soc. Am. Bull. 

 88:683-694. 



Rabinowitz, P. D., S. C. Cande, and J. L. La Brecque. 



1976. The Falkland Escarpment and Agulhas Fracture Zone: 

 the boundary between oceanic and continental basement at 

 conjugate continental margins. An. Acad. bras. Cienc. 48 

 (Suplemento):241-251. 



Rabinowitz, P. D., and J. L. La Brecque. 



1977. The isostatic gravity anomaly: key to the evolution of 

 the ocean-continent boundary at passive continental margins. 

 Earth Planet. Sci. Lett. 35:145-150. 



Plate Tectonics and Metallogenesis 



A fuller understanding of the origin and development of ore 

 deposits is needed to guide the search for new reserves of min- 



erals vital to industrial civilization. One of the significant impli- 

 cations of plate tectonic theory is that active processes along 

 plate margins relate in subtle ways to the formation both of 

 economic metal deposits and hydrocarbon accumulation. The 

 subject is a complex, multifaceted one that includes both sea- 

 floor- and mountain-building processes. The circum-Pacific belt, 

 characterized by active subduction zones, parallels to varying 

 degrees some of the world's major metallogenic provinces. At 

 one end of the system, hydrothermal processes along the 

 spreading centers of the ocean floor show evidence of metal 

 concentrations, and at the other end in the mountain belts, 

 suites of rocks in the zones of metal accumulation suggest deep 

 marine origin. Following the paths of the metals from the source 

 to the mine is a major scientific problem in Earth science that 

 the Seabed Assessment Program is supporting in part through 

 several projects. 



Studies of the western boundary of the Nazca Plate and the 

 Galapagos Hydrothermal Rift are major efforts to understand 

 the processes of crustal formation and metalliferous sediment 

 accumulation. The back-arc basins, until now largely uninvesti- 

 gated, are also possible sources of new crustal material. The 

 latter are situated along the Mariana-Philippine Transect of 

 the SEATAR project (Studies in East Asia Tectonics and 

 Resources). 



Correlation of processes along the active subducting margins 

 with the final cumulative products within the folded mountain 

 belts is a current major geological problem. The study processes 



56 



