What forms the basis for the deep ocean hot springs along the East Pacific Rise?

hot springs (geothermal vents) should be found at the active spreading centers along the mid-oceanic ridges, where magma, at temperatures over 1,000 °C, presumably was being erupted to form new oceanic crust. More exciting, because it was totally unexpected, was the discovery of abundant and unusual sea life - - giant tube worms, huge clams, and mussels - - that thrived around the hot springs.