Table 1. Chemical exchange between seawater and basalt in a 

 high-temperature (200-400°C) subseafloor hydrothermal 

 circulation system ( Edmond et al., 1980; Thompson, 1983) 



Constituent Basalt Seawater Oceanic Ridge/River* 



Copper (Cu) - + 



Iron ( Fe ) - + 



Manganese (Mn) + 1 



Zinc (Zn) - + 



Potassium (K) - + 2/3 



Lithium (Li) - + 10 



Rubidium (Rb) - + 



Barium (Ba) - + 2/3 



Calcium ( Ca ) - + 1 



+ 2/3 



1 

 1 

 Variable 

 ? Variable 



- = removal. 



+ = addition. 



* = Ratio of oceanic ridge flux to river input. 



