SECT, 3] 



PELAGIC SEDIMENTS 



665 



Table I 



Bulk Chemical Composition of Manganese Nodules from the Pacific and Atlantic 

 Oceans as Determined by X-Ray Spectrography« 



<* Concentrations are given in weight per cent. (Data from Mero, unpublished.) 



variabihty in the concentrations of cobalt, nickel, copper, iron and molybdenum 

 relative to manganese in the nodules. Arrhenius and Korkisch (1959) have 

 pointed out that eddy diffusion is an insufficient transport mechanism for a 

 number of the heavy metals found in manganese nodules, including the rare 

 earth elements, thorium and uranium. They consequently assume that the 

 vertical-transport mechanism described on page 677 below controls the transfer 



