Figure 1. World map showing the oceanic ridge system (divergent 

 plate boundaries where seafloor spreading occurs) and other 

 types of plate boundaries. The oceanic ridges in the 

 Atlantic Ocean and western Indian Ocean are slow-spreading 

 (full-rate <^ 4 cm/y). The oceanic ridges in the eastern 

 Indian Ocean and Pacific Ocean are faster-spreading with the 

 exception of the Gorda Ridge which has slow-spreading 

 characteristics similar to the Mid-Atlantic Ridge. 

 Locations of the TAG Hydrothermal Field at the Mid- 

 Atlantic Ridge and the Gorda Ridge are noted. 



