The maps of manganese distribution are being prepared so that they 

 may be used as overlays on maps showing distribution of other proper- 

 ties, such as detailed topography, heat flow, presence or absence of a 

 nepheloid layer, depth of horizons revealed by 3.5 kHz profiler, rate of 

 sedimentation, bottom current velocity, and local characteristics of the 

 earth's magnetic field. For example, if the map of distribution of man- 

 ganese deposits overlaid on sedimentary province charts shows that high 

 nodule concentration is associated with particular sediments, then the 

 lithologic properties of abyssal sediments and the development of man- 

 ganese nodules may be related. Similarly, if the map of manganese de- 

 posits overlaid on maps of bottom currents and local characteristics of 

 the magnetic field shows that high nodule concentration is associated with 

 certain relationships of current vector and magnetic vector, then geo- 

 magnetic electrokinetic potential and the occurrence of manganese nodules 

 may be related. 



Data obtained during the August 1971 preliminary cruise of 

 GEOSECS in the South Pacific have been made available to this study. 

 The vertical distribution of manganese and other metals in the water 

 column is being studied to determine the typical distribution and the 

 range of variation. An attempt is being made to determine whether or 

 not manganese concentration in sea water is an indicator of the presence 

 of nodules on the bottom. GEOSECS data on near-bottom particulate 

 matter are also being used in the study. 



Study of these nodules is of great scientific interest. Studies of the 

 control of precipitation and solution of the manganese and associated 59 



elements, the puzzles offered by the great age of the nodules, their shapes, 

 and their escape from accumulating finer sediments will yield information 

 of great value about other processes at the deep ocean floor. 



Presentation of the maps and overlays, results of these recent studies, 

 and other data in a workshop attended by leading U.S. and foreign ex- 

 perts on ocean bottom deposits will be a remarkable opportunity to gain 

 new understanding of the mechanisms of deposition of manganese nodules. 

 It seems possible that the Workshop will be a major turning point in man's 

 continuing relationship with these deposits so rich in nickel, copper, and 

 other important metals. 



