Preliminary Report on the Chemistry of Hydrothermal Solutions at 21° North, East Pacific Rise
A preliminary report is presented, of the information available to date on the chemistry of the 350° C hot springs on the EPR at 21° N. Three distinct fields were sampled by ALVIN in November 1979. The end-member solutions are completely depleted in magnesium and sulphate and are markedly acidic. The alkalies and alkaline earths are similar in their behavior to what was observed at Galapagos; however, there are significant differences. The waters are sulphide dominated with the H2S:Fe ratio being 3.5. The Fe:Mn ratio is 1.8. The vents are enriched in Zn relative to Cu with Zn:Cu equal to about 7. The strontium concentration in the end member is only a few percent above the normal sea water value. However, the isotopic composition is very similar to basalts. The large resulting flux of non-radiogenic strontium is necessary to the overall isotopic balance of the element in the oceans. The close compositional agreement between the 21°N and Galapagos solutions provides further evidence for the validity of the general calculations developed using the Galapagos data.
KeywordsHydrothermal Solution Spreading Center Black Smoker East PACIFIC Rise Ridge Crest
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