American dive area is also in the rift valley south of the primary 

 target. Archimede will make a few dives in the 1973 French dive area 

 to make 1974, however, will be in the north bounding fracture zone. 

 Cyana will work on the western and eastern scarps of the original 

 French area and also in the northern fracture zone. If time permits, 

 Aivin will make additional dives in either the north or south 

 bounding fracture zone. The principal tasks of the submersibles will 

 be to make detailed observations of lava flow morphology, fracture 

 systems, and vent structures and to establish the stratigraphic 

 sequence of intrusive and extrusive rocks of layer 2 and possibly 

 layer 3 in the rift valley walls and on the walls of a fracture zone. It is 

 also hoped that the submersibles will obtain data indicating 

 deformation on the rift valley walls and obtain a set of rock samples 

 carefully documented with respect to structural features, flow 

 boundaries, stratigraphic position, and geologic orientation. The 

 scientific objectives of the submersible work will be to identify the 

 active intrusion zone, to chart the zone using its magnetic, 

 bathymetric, and geothermal characteristics and relate these to the 

 broader tectonic framework inferred from the local seismicity. In 

 addition to photographic coverage of the terrain from the 

 submersibles and data logging of features seen, several bottom 

 instruments may be deployed by the submersibles. A magnetic 

 petrology lab and water sediment lab for processing and analyzing 

 recovered samples, libraries of all data, and facilities for followup 

 studies will be available on the Knorr. 



On board the Knorr, several ancillary experiments are planned to 

 complement the diving program. A heat flow program and 

 complementary gravity coring are planned for the northern fracture 

 zone to provide data to be used in support of Archimede operations. 

 The heat flow measurements will also complement planned studies 

 of submarine hydrothermal activity. Photography and magnetic 

 profiles over the area of the magnetic reversal boundary between the 

 Brunhes and Matayama Epochs are planned and will be followed up 

 by rock drilling. The use of sonobuoys is planned for 

 microearthquake monitoring, especially near the submersibles. 

 Bottom seismograph studies, current meter deployment, and 

 additional bottom photography will also be undertaken from the 

 Knorr. Acoustic frequencies for communication, navigation, and 

 depth sounding are being assigned to avoid interference among the 

 many vehicles in the area. 



An extensive bilingual operational report of the diving program 

 will be prepared at the end of 1974 to serve as a basis and catalyst for 

 further analyses. In 1975, a scientific symposium will be planned 

 and a composite scientific publication will be issued. 



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