8°N 



6°N 



4°N 



2°N 



2°S 



— I 1 1 r 



DETAILED SURVEY AREA 

 ^ SHALLOWER THAN 2000 M 

 = GALAPAGOS SPREADING 

 CENTRE 



8°N 



6° N 



4°N 



2° N 



2°S 



92° W 



88°W 



84°W 



80°W 



Figure 28. — Detailed suney area where ALVIN diving operations took place as part of the Galapagos Spreading Center 

 program. 



collaboration from scientists in Colombia, Ecuador, Peru, and 

 Chile. A broad spectrum of geophysical and geochemical 

 methods were used to investigate the possible connection be- 

 tween the oceanic plate tectonic cycle and the genesis of ore 

 deposits in the Andes. 



Several extensive and comprehensive research cruises 

 were conducted during 1972-75. Data were collected primarily 

 from the dynamic margins of the plate. The formation of new 

 crustal material along the East Pacific Rise provided valuable 

 insights in the processes of metalliferous sediment formation. 

 Detailed investigations of the Peru-Chile Trench elucidated 

 the processes of subduction. Analyses and interpretation of 



these data are scheduled for completion by 1978. Several ar- 

 ticles have already appeared in scientific journals. A special 

 synthesis volume is also being prepared to relate the research 

 results to the metallogenesis theme. A series of geological, 

 geophysical, and geochemical maps of the plate will accompany 

 this volume. 



Nazca Plate Bibliography 



Andrews, J. E., and A. Foreman, Jr. 1975. Sediment core 

 descriptions: RV Kana Keoki 1971 cruise. Eastern and 

 Western Pacific Ocean. Data Rep. No. 28, HIG-75-15 

 Hawaii Inst, of Geophys., Univ. Hawaii, 328 p. 



48 



