Multichannel seismic system tested by WHOI off Georges Bank 



data extends from the abyssal plains of the Sigsbee Deep and 

 along thesedimentary section under the Mexican Ridges. 



Plate Tectonics and Metallogenesis Studies 



There is increasing evidence that the processes creating 

 new sea floor along the spreading centers and its consumption 

 in the deep ocean trenches are uniquely related to formation of 

 certain types of mineral deposits. Scientists studying the Mid- 

 Atlantic Ridge, the Nazca Plate, and the Galapagos Rift Zone 

 are examining the sequence of rock units present and the role 

 of sea-floor hydrothermal circulation in the formation of 

 metalliferous sediment deposits. The Nazca Plate Study and 

 East Asia Study allow scientists to relate the processes of sub- 

 duction to mineral deposits in the overlying land masses, 

 and metallogenesis in the overlying land masses. 



East and Southeast Asia 



A workshop on metallogenesis and tectonic patterns in east 

 and southeast Asia was convened September 1973 in Bangkok, 

 Thailand, under the cosponsorship of the Committee for Co- 

 ordination of Joint Processing for Mineral Resources in Asia 

 Offshore Areas, the UNESCO Intergovernmental Oceanographic 

 Commission, and the NSF Office for IDOE. The purpose of this 

 workshop was to consider the tectonic development of eastern 

 Asia and its relation to metalliferous ore and hydrocarbon 

 genesis. 



Early in the planning phase it was recognized that an ade- 

 quate synthesis of marine geological and geophysical data for the 

 region did not exist. To gain a thorough understanding of the 

 known tectonic patterns, particularly of the marine areas, and 

 to make efficient application of existing data, it was strongly 

 recommended that efforts be made to compile existing informa- 

 tion for the east and southeast Asian areas. This summary 

 will lead to the production of an atlas of marine geological and 

 geophysical data for the seas of the east Asia region. 

 Scientists at Lamont-Doherty Geological Observatory, Scripps 

 Institution of Oceanography, 'Woods Hole Oceanographic Insti- 

 tution, and Cornell University are involved in the compilation 

 program. 



Based on this synopsis of existing data, field programs have 

 been initiated in the Philippine, Banda, and Sunda Arc regions 

 (fig. 17). Scientists from Lamont, Scripps, UCLA, and the 

 Colorado School of Mines are working with Philippine counter- 

 parts to obtain better information about the processes that con- 

 trol metal distribution on the island of Luzon. This work will be 

 closely coordinated with marine studies of the Philippine Sea in 

 an attempt to relate both subduction and the tectonic history of 

 this area to metal distribution patterns. 



Marine geophysical and geological studies and island map- 

 ping programs are being carried out in the Banda and Sunda 

 arc regions. Scientists from Scripps and Woods Hole, and also 

 Indonesia will be carrying out a joint study of the structure 



35 



