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长期以来,人们就猜测在大洋扩张中心有热液活动存在,但只是在四年前,才第一次直接观察到了这种现象。1977年春,阿尔文号潜水艇在加拉帕戈斯扩张脊(西经86°)2500米深处发现了热泉田。这个热泉出口处的温度高出周围海水(~2℃)15℃,并在周围玄武质枕状熔岩上形成一层薄的氧化锰外壳。在轴外洋壳(年龄为30万年)上的沉积物中还发现了由热液产生的绿脱石(富铁粘土矿物)组成的小丘(被纯二氧化锰壳层复盖)区。
It has long been speculated that there is hydrothermal activity in the center of ocean expansion, but this phenomenon was first observed directly only four years ago. In the spring of 1977, the Alwar submarine discovered a hot spring field at a depth of 2500 meters in the Galapagos expanse of the ridge (86 ° west longitude). The temperature at the exit of this hot spring was 15 ° C above the surrounding seawater (~ 2 ° C) and a thin layer of manganese oxide was formed on the surrounding basaltic pillow lava. Also found in the sediments on the outer epicontinental (age 300,000 yr) are hills of pyroxene (iron-rich clay minerals) produced by hydrothermal fluids (covered by a pure manganese dioxide shell).